124-21 PHOTOCYCLOADDITIONS OF a, 6 -UNSATURATED LACTONES WITH ACRYLONITRILE AND ITS a-CHLORO AND a-ACETOXY DERIVATIVES

J e a n P i e r r e L a f o n t a i n e

B.Sc, , B i s h o p s U n i v e r s i t y , 1 9 8 1

A T H E S I S SUBMITTED I N P A R T I A L FULFILLMENT

OF THE REQUIREMENTS FOR THE DEGREE OF

MASTER O F S C I E N C E

@ Jean

SIMON

t h e Department

o f

C h e m i s t r y

P i e r r e L a f o n t a i n e 1 9 8 7 FRASER U N I V E R S I T Y

June 1 9 8 7

A l l r i g h t s r e s e r v e d . T h i s work may n o t be reproduced i n w h o l e o r i n p a r t , by p h o t o c o p y

o r by o t h e r means, w i t h o u t p e r m i s s i o n of t h e a u t h o r ,

-ii-

APPROVAL

Name : J,P. Lafontaine

Degree: Master of Science

T i t l e of Thesis: [ 2 + 2 ] ~hotocycloadditions of cr , ,8 -Unsaturated Lactones w i t h

Acrylonitri le and i ts a-Chloro and tr-Acetoxy Derivatives

Examining Committee:

Chairman: Dr. T. Bell

D r . A.C. -OehlschJ#ger, Senior Supervisor

\ - Dr. K.N. \Slesso$

-

1

Dr. R . i i ~ ~ ' b % ~ o y - '

~r*. ~ n i a u , Internal Examiner

4

Date Approved: k/ 2 7, /ff7

PART l AL COPYRIGHT LICENSE

I hereby g ran t t o Simon Fraser U n i v e r s l t y the r i g h t t o lend

my thes is , p r o j e c t o r extended essay ( t h e t i t l e o f which i s shown below)

t o users o f the Simon Fraser Un ive rs i t y L ibrary, and t o make p a r t i a l o r

s i n g l e copies on ly f o r such users o f i n response t o a request from the

l i b r a r y o f any o ther un ive rs i t y , o r o the r educational I n s t i t u t i o n , on

i t s own behalf o r f o r one o f I t s users. I f u r t h e r agree t h a t permission

f o r m u l t i p l e copying o f t h i s work f o r scho la r l y purposes may be granted

by me o r the Dean o f Graduate Studies. I t i s understood t h a t copying-

o r p u b l i c a t i o n o f t h i s work f o r f i n a n c i a l ga in sha l l not be allowed

wi thout my w r i t t e n permission.

Author:

A B S r n C T

The [ 2 + 2 ] p h o t o c y c l o a d d i t i o n s of s e v e r a l

a , $ -unsa tu ra t ed Y and 6 l a c t o n e s w i t h a c r y l o n i t r i l e

and i ts a -acetoxy and a - c h l o r o d e r i v a t i v e s were

i n v e s t i g a t e d . I t was found t h a t t h e r e a c t i o n s were b e s t

performed i n a c e t o n i t r i l e and t h a t i r r a d i a t i o n through a

Vycor o r Q u a r t z f i l t e r was r e q u i r e d .

S e v e r a l t r i p l e t s t a t e s e n s i t i z e r s were i n v e s t i g a t e d

and found t o r e a c t more q u i c k l y t h a n t h e 6 l a c t o n e s wi th

t h e o l e f i n s s t u d i e d . T h i s p r e c l u d e d t h e i r u se t o promote

t h e [ 2 + 2 1 c y c l o a d d i t i o n .

The 6 l a c t o n e s s t u d i e d underwent c y c l o a d d i t i o n wi th

a c r y l o n i t r i l e and its a - c h l o r o and a -ace toxy d e r i v a t i v e s

t o g i v e m i x t u r e s of t h e two d i a s t e r e o m e r i c 6 adduc t s i n

moderate y i e l d s . These a d d u c t s were shown t o be

p h o t o s t a b l e b u t were r e a d i l y ep imer ized w i t h a lkox ides .

The Y l a c t o n e s s t u d i e d underwent c y c l o a d d i t i o n wi th

a c r y l o n i t r i l e t o g i v e m i x t u r e s of f o u r 1:l adduc t s which

were on ly p a r t i a l l y r e s o l v a b l e by chromatography. These

a d d u c t s were shown t o be p h o t o s t a b l e b u t were decomposed

by a l k o x i d e s . The Y l a c t o n e s d i d n o t undergo

p h o t o a d d i t i o n w i t h a - c h l o r o o r a -ace toxy a c r y l o n i t r i l e .

Molecular mechanics ( M M - 2 ) c a l c u l a t i o n s were

petformed on s e v e r a l sys tems t o de t e rmine t h e r e l a t i v e

s t r a i n e n e r g y be tween d i f f e r e n t i s o m e r s of t h e a d d u c t s .

E q u i l i b r i u m c o n c e n t r a t i o n s were c a l c u l a t e d f rom t h e MM-2

c a l c u l a t e d e n e r g i e s and found t o b e i n good ag reemen t w i t h

t h o s e o b t a i n e d i n base e q u i l i b r i a t i o n e x p e r i m e n t s .

V i c i n a l h y d r o g e n c o u p l i n g c o n s t a n t s (nmr) d e r i v e d from

MM-2 c a l c u l a t e d d i h e d r a l a n g l e s were found

t o be i n good a g r e e m e n t w i t h e x p e r i m e n t a l l y d e t e r m i n e d

v a l u e s .

ACKNOWLEDGEHENTS

I would l i k e t o acknowledge t he help and support

provided by t he following people. Dr. A.C. Oehlschlager,

Dr. B.D. Johnston, Dr. H.D. P ierce , Dr. J , Mil lar , Dr. E.

Czyzewska and Dr. B.M. Pinto.

I would e spec i a l l y l i k e t o thank

D r . A.C. Oehlschlager f o r the enthusiasm, ideas and

pat ience he provided. I would a l s o l i k e t o thank

M. Tracey and G . Owens f o r the exce l l en t spectroscopic

se rv ices , and M.K. Yang f o r the elemental analys is .

TABLE OF CONTENTS

Abstract

Acknowledgements

List of Tables

List of Schemes and Figures

Introduction

Results and Discussion

Experimental

References

iii

v

vii

viii

L I S T OF TABLES

Table 1

Paqe

Summary of Reactions of 6 -Lactones

Table 2 Summary of M M 2 Calculat ions f o r 6-Lactones 18

Table 3 Calculated Equilibrium Populations

Table 4 - Table 5 -

Summary of Experimental NMR Chemical

Summary of React ions of Y -Lactones

S h i f t s

Table 6 Summary of M M 2 Calculat ions f o r Y-Lactones 28 - Table 7 U.V. Spec t ra l Parameters

Figure 1

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Fiqure 2

Figure 3

Fiqure 4

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Fiqure 5

Scheme 10

Scheme 11

LIST OF SCHEMES AND FIGURES

Structure of Lineatin (1) - Silverstein's Synthesis of Lineatin

Mori's Synthesis of Lineatin

Mori's Synthesis of Lineatin

White's Synthesis of Lineatin

Weiler Is Synthesis of Lineatin

Mechanism of [2+2] Photocycloaddition

Mechanism of Regiochemical Control

Polarity of Olef ins

Photoaddition of Acrylonitrile to 2-Cyclohexenone

Photoaddition of Acrylonitrile to 2-Cyclohexenone

Photoaddition of Acrylonitrile to 2-Acetoxy-3-methyl-2-cyclopentenone

Retrosynthetic Analysis of Lineatin

Structure of Lactones 6-9 - - Photoaddition of Acrylonitrile to Anhydromevalonolactone (6) - Base Isomerization of 10 and 11 - -

Page

1

L i s t of Schemes and F i g u r e s (cont'd)

Scheme 12

Scheme 13

Fiqure 6

Scheme 14

Scheme 15

Scheme 16

Figure 7

Photoaddition of a-Chloro and a-Acetoxyacrylonitrile to Anhydromevalonolactone (5)

Photoaddition of Acrylonitrile and its a-Chloro and a -Acetoxy Derivatives to 2-Pentenolide (1)

Bicyclic Numbering System

Photoaddition of Acrylonitrile to 2-Butenolide (8)

Photoaddition of Acrylonitrile to 2,3,3-Trimethyl-2-buten-1,4-olide (2)

Synthesis of 2,3,3-Trimethlyl-2-buten- l,4-olide (2) Photolysis Apparatus

-1-

INTRODUCTION

The [ 2 + 2 ] p h o t o c y c l o a d d i t i o n of a , B - u n s a t u r a t e d

k e t o n e s w i t h o l e f i n s is a v a l u a b l e s y n t h e t i c r o u t e t o a

v a r i e t y of b i c y c l o [ n . 2 . 0 ] f u s e d r i n g s y s t e m s . Many of

t h e s e r e a c t i o n s h a v e been a p p l i e d t o t h e t o t a l s y n t h e s i s

of n a t u r a l p r o d u c t s l - Our i n t e r e s t i n d e v e l o p i n g a n

e f f i c i e n t s y n t h e t i c r o u t e t o ( + ) l i n e a t i n ( A ) , t h e

a g g r e g a t i o n pheromone o f t h e a m b r o s i a b e e t l e Trypodendron

l i n e a t u r n ( 0 l i v i e r ) 2 r 3 , l e d u s t o i n v e s t i g a t e t h e p o t e n t i a l

of t h i s r e a c t i o n i n t h e e l a b o r a t i o n o f t h e c a r b o n s k e l e t o n

of t h i s pheromone.

Figure 1 : Lineatin(L)

The u n u s u a l t r i c y c l i c acetal s t r u c t u r e of l i n e a t i n

h a s evoked c o n s i d e r a b l e s y n t h e t i c i n t e r e s t and t h e r e have

been a number o f r o u t e s reported3'11, i n c l u d i n g s e v e r a l

u t i l i z i n g a [ 2 + 2 ] p h o t o a d d i t i o n t o c o n s t r u c t t h e

c y c l o b u t a n e r i n g 3 t 4 , 6 ~ 8 .

The f i r s t p h o t o c h e m i c a l r o u t e t o r acemic l i n e a t i n was

r e p o r t e d by S i l v e r s t e i n and c o w o r k e r s 3 and is d e p i c t e d i n

Scheme 1. T h i s r o u t e p r o d u c e d o n l y microgram amounts of

impure l i n e a t i n , p a r t l y due t o t h e poor r e g i o s e l e c t i v i t y

i n the photoaddit ion of v inyl a c e t a t e t o

anhydromevalonolactone ( 6 ) . -

Scheme 1:

Two o the r photochemical r ou t e s were subsequently

developed by ~ o r i 4 and a r e depic ted i n Schemes 2 and 3 .

The route ou t l i ned i n Scheme 2 is twelve s t e p s and has

only produced milligram amounts of 1. One of the

p r o h i b i t i v e f e a t u r e s of t h i s scheme was t he poor

r e g i o s e l e c t i v i t y i n the photoaddi t ion of vinyl a c e t a t e t o

- t he s u b s t i t u t e d cyclopentene. The mixture of isomeric

a c e t a t e s obtained proved t o be inseparab le u n t i l a f t e r

k e t a l i z a t i o n and oxidat ion t o t h e cyclobutanone. T h i s

route gave a 2.5% y i e l d of t h e bicyclo[3.2.0lbutanone

which had the r equ i red regiochemis t ry f o r e l abora t ion

t o - 1.

Scheme 2:

isomers

I n an a t t empt t o circumvent t h e problem of poor

r e g i o s e l e c t i v i t y t h e Japanese workers developed the route

shown i n Scheme 3 . The 3:2 mixture of isomeric a c e t a t e s

. t h a t was produced v i a t h i s rou te a l s o proved t o be

inseparable . The problem was unexpectedly solved when the

undesired 6-regioadduct underwent a r e t r o a l d o l r eac t ion

dur ing t h e subsequent n i t rosa t ion- reduc t ion . T h i s

e n a b l e d t h e i n v e s t i g a t o r s t o o b t a i n t h e d e s i r e d p r o d u c t i n

4 .8% y i e l d which was e l a b o r a t e d t o i n 0.8% o v e r a l l

y i e l d .

Scheme 3:

A d i f f e r e n t s t r a t e g y was used by Whi te and coworkers6

and is summarized i n Scheme 4 . Whi te , e t a 1 hoped t o

c i rcumvent t h e p rob lems o f p o o r r e g i o c h e m i c a l c o n t r o l

d u r i n g t h e p h o t o a d d i t i o n of a k e t e n e e q u i v a l e n t by u s i n g

a c e t y l e n e and i n t r o d u c i n g a f u n c t i o n a l i t y a t C 7

r e g i o s p e c i f i c a l l y by u s e of h i n d e r e d o rganoboranes . I t

was found, however, t h a t t h e c y c l o b u t e n e r e s i s t e d

h y d r o b o r a t i o n by d i s i a m y l b o r a n e and o t h e r h i n d e r e d

b o r a n e s . Use of d i b o r a n e i t se l f g a v e a 3 : l m i x t u r e of t h e

r e g i o i s o m e r i c a l c o h o l s . F o r t u n a t e l y , it was u n n e c e s s a r y

t o s e p a r a t e t h e m i x t u r e as t h e l ess s t e r i c a l l y h i n d e r e d

a l c o h o l underwent r e a c t i o n w i t h t o s y l c h l o r i d e much f a s t e r

t h a n t h e more h i n d e r e d i somer and t h e r e s u l t i n g t o s y l a t e

was e a s i l y s e p a r a t e d from u n r e a c t e d a l c o h o l . T h i s r o u t e

r e s u l t e d i n a s e v e n s t e p s e q u e n c e w i t h a n o v e r a l l y i e l d

o f 14%.

Scheme 4:

The l a t e s t s y n t h e s i s of l i n e a t i n i n v o l v i n g a [ 2 + 2 ]

p h o t o a d d i t i o n was r e p o r t e d by w e i l e r 8 e t a 1 i n 1981 and is

. . -6- . -

depicted in scheme- 5. This five step route to lineatin

provided gram quantities of *lineatin in an overall yield

of 10% from anhydromevalonolactone. This route, as the

previous ones, suffered from low regioselectivity in the

photoaddition step. Changes in solvent, temperature and

steric requirements of the allene did not improve the

regioselectivity. All sets of isomeric photoadducts

proved inseparable and.the synthesis was continued to

eventually provide a mixture of lineatin(l1 and - isolineatin(2). These two compounds were readily - separable by column chromatography but the high volatility

of the products led to significant loss of material,

considerably-reducing the efficiency of this route. -

Scheme 5; I

-7-

Clear ly , the photochemical r ou t e s t o l i n e a t i n have

a l l su f fe red from e i t h e r poor r e g i o s e l e c t i v i t y i n the

photoaddit ion s t e p o r , a s i n White's case , poor

r e g i o s e l e c t i v i t y i n the ox ida t ion of t he cyclobutene. We

f e l t t h a t [ 2 + 2 ] photoaddit ion s t i l l held promise f o r an

e f f i c i e n t syn thes i s of l i n e a t i n bu t a ketene equivalent

w i t h a high r e g i o s e l e c t i v i t y favor ing a B adduct was

required.

The genera l ly accepted mechanism f o r the [2+2]

photoaddit ion between a,B-unsaturated ketones and o l e f i n s

a s proposed by corey12 and de ~ a ~ o * ~ is depicted

schematical ly i n Figure 2.

Figure 2: l~*+ 0 -----c s~*+ o - ['Eo]'

BIR

Products

E= Enone O=Olefin BlR =Blradlcal Intermediate

The absorpt ion of a photon by t he enone causes

a n-lr* t r a n s i t i o n producing a s i n g l e t exci ted s t a t e

species . T h i s undergoes in tersys tem cross ing t o a t r i p l e t

exci ted s t a t e spec ies which forms an exci ted s t a t e complex

or exciplex w i t h the ground s t a t e o le f in . The exciplex

can then col lapse t o a 1,4-biradical which can close t o

form the cyclobutane. The reg iose lec t iv i ty of the

reaction is thought t o be controlled by the or ien ta t ion

of the d ipoles i n the exciplex. Carey ~ o s t u l a t e d l 2 tha t

polar izat ion of the excited s t a t e enone was reverse t o

t h a t of the ground s t a t e system. Since the preferred

or ien ta t ion of the dipoles i n the exciplex is t h a t i n

which the d ipoles a r e opposed then subst i tu ted o le f ins

polarized by e l ec t ion withdrawing groups should

p re fe ren t i a l ly give r i s e t o B subs t i tu ted regioadducts

a s depicted i n Figure 3.

Ab i n i t i o calculat ions of the charge d i s t r ibu t ion i n

excited s t a t e planar a, B -unsaturated ketonesl3.14 give

conf l ic t ing r e s u l t s b u t the experimental

results12,15,16,17 are e n t i r e l y cons is ten t w i t h t h i s

postula te .

The po la r i ty required f o r the p re fe ren t i a l formation

of the B adduct is s a t i s f i e d by a c r y l o n i t r i l e and its

a-chloro and a-acetoxy der iva t ives . (Figure 4 ) .

Figure 4: Folarity of Some Ground State Olef ins

OAc

To the best of our knowledge, there have been no

reports on the successful photoaddition of a-chloro or

a-acetoxyacrylonitr i le w i t h a , @ -unsaturated ketones or

lactones. The photoaddit ion of acryloni t r i l e w i t h

unsaturated ketones has been reported12t17f1* however.

corey12 found t h a t a c r y l o n i t r i l e added t o 2-cyclohexenone

t o give 4 products, of which the major products were the

c i s fused isomeric B -regioadducts (Scheme 6 ) . -

Scheme 6:

cantre1117 a l s o found tha t the - c i s fused

6-regioadducts were the pr incipal products i n the reaction

between 3-methyl-2-cyclohexenone and a c r y l o n i t r i l e (Scheme

7 ) . I n cont ras t t o Corey's work Cantrel l reported tha t

ac ry lon i t r i l e added much f a s t e r t o a , B -unsaturated

ketones than o le f ins subs t i tu ted w i t h e lectron r ich

heteroatom or a lky l groups.

Scheme 7:

~ u r u s a k i l 8 a l s o found tha t the - c i s fused

B-regioadduct was the major product between a f i v e

membered cyc l i c enone, 2-acetoxy-3-methyl-2-cyclopentenone

and a c r y l o n i t r i l e (Scheme 8 ) . The s t ruc tu re of the major

product was determined by x-ray crystal lographic analysis .

Scheme 8:

+ 2 other isomers

T h u s w i t h both f ive and s i x membered cyc l ic enones

a c r y l o n i t r i l e was found t o p re fe ren t i a l ly give r i s e t o

the B-regioadduct as predicted by the simple dipole

in te rac t ion model.

Our re t rosynthe t ic ana lys i s of a photochemical route

t o l i n e a t i n , which was s imi la r t o Weiler's, is depicted

i n Scheme 9 and is predicated on a c r y l o n i t r i l e adding t o

anhydromevalonolactone t o give the - c i s fused

Scheme 9: Retrosynthesis of Lineatin

The 2+2 photoaddition of olef i n s t o a , B -unsaturated

lactones has been reported19,20 t o proceed i n a manner

s imilar t o t h a t of a , B -unsaturated ketones, w i t h several

notable dif ferences . Ether was found t o be a poor solvent

fo r the reaction as hydrogen abs t rac t ion from the solvent

competed w i t h cycloaddition, The second major difference

was the report20 t h a t a c r y l o n i t r i l e d i d not undergo

photoaddition t o a var ie ty of subst i tu ted a , B -unsaturated

lactones, including anhydromevalonolactone. T h i s resu l t

was surpr is ing i n view of preliminary work done i n our

laboratory21 i n which it was found tha t ac ry lon i t r i l e

added t o anhydromevalonolactone i n an e f f i c i e n t although

stereochemically undefined manner.

The present study was undertaken w i t h several goals

i n mind: (1) t o inves t iga te the conditions necessary f o r

e f f i c i e n t [ 2 + 2 ] photocycloaddition of a,B -unsaturated

lactones - - 6-9 w i t h a c r y l o n i t r i l e as well a s i ts a-chloro

and a-acetoxy der iva t ives ; ( 2 ) t o e lucidate the s t ruc ture

and stereochemistry of the products obtained, ( 3 ) t o

apply the cycloaddit isn react ion t o t h e synthes is s f

l i nea t in .

Figure 5:

RESULTS AND DISCUSSION

I n i t i a l l y we investigated the photoaddition of

acryloni t r i l e and anhydromevalonolactone ( 6 ) - i n a var ie ty

of solvents (experiments ~ 1 - A 7 ) . The reports19 by

previous workers indicated t h e i r standard conditions

employed acetone a s the solvent. The use of acetone as a

t r i p l e t s t a t e s e n s i t i z e r and solvent f o r photoreactions

is well known20,22* I t is e f f i c i e n t f o r promoting the

cycloaddition of ethylene and acetylene t o

a , $-unsaturated lactoneslg. Our own attempts t o employ

acetone a s the solvent led only t o production of complex

mixtures of low boi l ing products and recovery of the

s t a r t i n g lactones. Acetone has a UV cutoff around

330 nm23 and a r e l a t ive ly s t ab le t r i p l e t s t a t e . I t ac t s

e f f ec t ive ly a s a f i l t e r and the cycloaddition can only

proceed i f the enone is sens i t ized by the t r i p l e t s t a t e

acetone.

We considered the poss ib i l i t y the t r i p l e t s t a t e

a r i s i n g from sens i t ized ac t iva t ion would be d i f fe ren t

. from tha t a r i s i n g from d i r e c t ac t iva t ion l5 .

The p o s s i b i l i t y of an excited s t a t e enone, a r i s ing

from t r i p l e t s t a t e sens i t i za t ion by acetone (Et=330

~~ / rno le )4O, being unable t o react w i t h ac ry lon i t r i l e

was c o n s i d e r e d u n l i k e l y i n v i ew of t h e e f f i c i e n t

s e n s i t i z e d r e a c t i o n o f e n o n e - 6 w i t h e t h y l e n e and

a c e t y l e n e . T h i s r e a c t i o n a l s o p r o c e e d e d e f f i c i e n t l y when

d i r e c t a c t i v a t i o n was used6 .

To a i d u s i n s e l e c t i o n o f p h o t o c y l o a d d i t i o n

c o n d i t i o n s w e i n v e s t i g a t e d t h e i n t e r a c t i o n between t h e

o l e f i n s of i n t e r e s t and a c e t o n e . I t was found t h a t

s o l u t i o n s of a c r y l o n i t r i l e and i t s a - c h l o r o and a -ace toxy

d e r i v a t i v e s were t h e r m a l l y s t a b l e b u t r a p i d l y formed

complex m i x t u r e s o n i r r a d i a t i o n i n t h i s s o l v e n t .

S o l u t i o n s o f o l e • ’ i n and l a c t o n e 5 i n a c e t o n e produced

similar p r o d u c t m i x t u r e s when i r r a d i a t e d . Only t r a c e

amounts of t h e 1:l a d d u c t s were d e t e c t e d by GLC.

We were u n a b l e t o c o n v e n i e n t l y m o n i t o r t h e

c o n c e n t r a t i o n o f a c r y l o n i t r i l e and a - c h l o r o a c r y l o n i t r i l e

by GLC b u t t h e a - a c e t o x y a c r y l o n i t r i l e peak was

s u f f i c i e n t l y s e p a r a t e d f r o m t h e s o l v e n t peak t o permit

r e l i a b l e q u a n t i f i c a t i o n . I t was f o u n d t h a t t h e

c o n c e n t r a t i o n of t h i s o l e f i n was c o n s t a n t i n t h e d a r k and

d e c r e a s e d r a p i d l y upon i r r a d i a t i o n . We conc luded from

t h e s e e x p e r i m e n t s t h a t a c e t o n e r e a c t e d w i t h t h e o l e f i n s

- f a s t e r t h a n t h e o l e f i n s were r e a c t i n g w i t h 6. - Next we s t u d i e d t h e i n t e r a c t i o n of o t h e r t r i p l e t

s e n s i t i z e r s w i t h t h e o l e f i n s i n a c e t o n i t r i l e s o l u t i o n s

(UV c u t o f f 1 9 0 nm)23. A Corex f i l t e r was used i n t h e s e

experiments t o permit ac t iva t ion of only the sens i t izers ,

acetophenone ( E t = 3 1 0 ~d /mole ) lo and hexamethylbenzene

(Et=330 ~ ~ / m o l e ) ~ O . We found t h a t a l l combinations of

o l e f i n and sens i t i ze r led t o complex mixtures upon

i r r a d i a t i o n . However, a c e t o n i t r i l e solut ions of the

s e n s i t i z e r and a hydrocarbon i n t e r n a l standard were

photostable, indicating t h a t s e n s i t i z e r was reacting w i t h

o l e f i n and not w i t h solvent. It was a l s o found tha t i n

the presence of the s e n s i t i z e r s tes ted the photoaddition

of - 6 w i t h ac ry lon i t r i l e and its a-chloro and a-acetoxy

der iva t ives d i d not proceed.

We did not investigate the nature of the photo-

react ion between the s e n s i t i z e r and the o le f ins as they

appeared t o be of l i t t l e syn the t i c value. Other workers

have reported25,26,27 tha t acetone adds t o carbonyls and

other polarized n-systems t o form oxetanes. These

primary photoproducts can undergo complex secondary

thermal or photochemical reactions.

Use of other UV t ransparent solvents , such as

methanol, isopropanol and e ther , led t o the formation of

complex mixtures. The desired 1:l photoadducts were only

- detected a s minor components. Generally i n these

solvents consumption of the lactone - 6 ceased a f t e r

several hours of i r r ad ia t ion leaving 40-80% unreacted.

Use of these solvents led t o production of much polymeric

mater ia l t h a t i n t e r f e r e d w i t h the t ransmission of l i g h t

and was l i k e l y responsib le f o r t he s luggishness of the

react ion. In add i t i on t o the p r o l i f i c production of t a r s

and polymers, t he se so lven t s have a l s o been r e ~ o r t e d l g t o

r eac t with photo-act ivated enones by abs t r ac t i on of a

hydrogen atom.

The photochemical r eac t ions of lac tones 7-9 w i t h - - a c r y l o n i t r i l e and i ts a-chloro and a-acetoxy de r iva t i ve s

were ca r r i ed ou t i n acetone, e t h e r and methanol w i t h

e s s e n t i a l l y t he same r e s u l t s a s above.

In summary, w e have found t h a t a c r y l o n i t r i l e and its

a-chloro and a-acetoxy de r iva t i ve s r e a c t w i t h acetone

f a s t e r than w i t h any of the l ac tones s tudied . These

o l e f i n s a l s o reacted w i t h o the r t r i p l e t s t a t e s e n s i t i z e r s

under condi t ions i n which only t h e s e n s i t i z e r s were

absorbing.

I r r a d i a t i o n of - 6 w i t h a c r y l o n i t r i l e using

a c e t o n i t r i l e a s t he solvent led t o t he formation of

cycloaddi t ion products - 1 0 and - 11 which were separable by

f l a s h chromatography.

Scheme 10:

These photoadducts (Table 1) exhibited the expected

molecular ion peaks by MS. GC/MS samples were usually

analysed in CI mode as the molecular ion peak was weak

and sometimes absent when EI was used. The possibility

that the adducts were the isomeric oxetanes or exocyclic

olefins was eliminated upon examination of their 13c nmr

spectra. The expected signals due to carbonyl carbons

were evident and no signals due to olefinic carbons were

observed in the isolated mixtures.

For this [2+2] photocycloaddition there are eight

possible isomeric bicyclic[4.2.0] structures differing at

the ring-junction stereochemistry (cis and trans fused), nitrile regiochemistry (13 - and - Y regioisomers) and the nitrile stereochemistry (endo and = I .

We first turned our attention to the ring-junction

stereochemistry of - 10 and - 11.

There were previous reports12r28,29 of trans-f used

bicyclo[4.2.0]octanones arising from photochemical

cycloaddition of electron rich olefins to

2-cyclohexenones. The trans-fused [4.2.01 compounds

were characterized by their rapid and complete

isomerization to the less strained - cis fused compounds

with acid, base or heat12r29. MM2 (1985 Force ~ i e l d ) ~ ~

calculations of the relative strain energies showed that

the AE (JE=Etrans-Ecis) was ca. 40 ~ ~ m - l for the f4.2.01 - 7

series (Table 2) and - ca. 105 K J ~ ' ~ for the [3.2.01

Table 1: Summary of Reactions o f d-Lactones

- Yield % - 77 64 54 62 5 6 64 65 60 - 2 9 - n -

endo-CN Product % R,

H H CI C I

OAc OAc H H

C I CI

OAc OAc

Ixperiment A1 A 2 81 82 C1 C2 D 1 D2 E 1 E2 F1 F2

Table 2: Summary o f MM2 Calculations for &-Lactones

cis trans

a . Coupling Constant J Calculated from Dihedral Angle Oby ICarplus3' Equation i n the form;

R .

H

H

CH,

CH,

R,

H

CN

H

CN

Table 3: J= A $. BCOSO + C C O S ~ @

R,

CN

H

CN

H

Isomer Pair

17:18

10:11 17~31

~~ui l ibr iurn '

cis Isomer

17

18 10

AE KJ

2.2 4.1

40.0

Population

71:29 84:16

100:O

K at 2S•‹C

2.43

5.20

10'

where A=7, B=-1, C=5.

Stra in

%r?Y 143.8 146.0 144.2

11 1 148.3

@ti,-H

115 2.9

135

1.5

a J ~ I - ~

4.2 11.0 7.7 11.0

trans Isomer

31

32

33

Strain Energy KJm-

169.9

173.0 184.2

34 192.1

ser ies . T h e s e s t r a i n e n e r g i e s a re i n k e e p i n g w i t h

reports t h a t i s o m e r i z a t i o n o f t h e t r a n s f u s e d t o cis - f u s e d b i c y c l o [ 4 . 2 . 0 l o c t a n e s is e s s e n t i a l l y comp le t e30 .

E x p e r i m e n t a l l y it was f o u n d t h a t t r e a t m e n t o f t h e

p h o t o a d d u c t s - 1 0 a n d - 11 w i t h a l u m i n a d i d n o t a f f e c t a n y

c h a n g e s i n e i t h e r t h e p u r e compounds o r m i x t u r e s o f

p h o t o a d d u c t s . T h e s e are c o n d i t i o n s w h i c h s h o u l d h a v e

r e s u l t e d i n t r a n s -cis - i s o m e r i z a t i o n l 2 . I t was

t h e r e f o r e c o n c l u d e d t h a t p h o t o a d d u c t s - 1 0 a n d - 11 p o s s e s s e d

t h e - c i s r i n g f u s i o n .

We n e x t t u r n e d a t t e n t i o n t o t h e r e g i o c h e m i s t r y o f

t h e n i t r i l e i n - 1 0 a n d - 11. The B - r e g i o c h e m i s t r y o f t h e

n i t r i l e was e v i d e n t from t h e c o u p l i n g p a t t e r n e x h i b i t e d

by t h e p r o t o n a t C 1 . Thus w e o b s e r v e d d o u b l e t s i n b o t h

1 0 a n d 11 as would be e x p e c t e d of B - r e g i o i s o m e r s . - - H a v i n g a s s i g n e d t h e s t e r e o c h e m i s t r y of t h e r i n g

f u s i o n a n d d e d u c e d t h e r e g i o c h e m i s t r y of t h e n i t r i l e

s u b s t i t u e n t we n e x t examined t h e s t e r e o c h e m i s t r y of t h e

n i t r i l e c o n f i g u r a t i o n i n - 1 0 a n d - 11. We u s e d MM2

c a l c u l a t i o n s t o estimate t h e d i h e d r a l a n g l e s a n d r e l a t i v e

s t r a i n e n e r g i e s of - e n d o a n d e x o n i t r i l e i s o m e r s 1 1 : l O . - -- T h e s e c a l c u l a t i o n s are summar i zed i n Table 2. The

e x p e r i m e n t a l l y o b s e r v e d c o u p l i n g c o n s t a n t s be tween H 1 a n d

H g o f 7 a n d 11 Hz were i n good a g r e e m e n t w i t h t h e

p r e d i c t e d 3 8 c o u p l i n g c o n s t a n t s o f 7 .7 a n d 1 1 . 0 Hz f o r

-20-

photoadducts - 10 and - 11 respectively. O n t h i s basis we

assigned - exo-CN stereochemistry t o the major product - 10

and - endo-CN stereochemistry t o 2. Both the experimental

and MM2-derived coupling constants were i n good agreement

w i t h the l i t e r a t u r e ~ a l u e s 2 9 , 3 ~ of Jcis = 10.4 - 9.0 Hz - and Jtrans = 6.6 - 3.2 Hz fo r s imi la r fused cyclobutane

systems.

MM2 ca lcula t ions were a lso used i n another fashion.

Mixtures of epimers tha t are equi l ibrated through common

intermediates give mixtures, the compositions of which

re f l ec t the r e l a t i v e product en.erg$es30132. If the

r e l a t ive energies of the products a re known then

equilibrium .populations can be calculated30. Accordingly

we calculated ( M M 2 ) the re la t ive energies of a l l possible

bicycloI4.2.0]octanone photoadducts. The pert inent

calculations a re summarized i n Table 3.

The pure adducts - 1 0 and - 11 were t reated w i t h sodium

ethoxide i n ethanol29 and found t o rzipidly equi l ibra te t o

80:20 mixtures of -- 10 : l l a t room temperatures. T h i s was

i n good agreement w i t h the predicted r a t i o of 84:16

exo:endo supporting our i n i t i a l assignment of the C8 - stereochemistry.

Table 7: Spectral Parameters E 8 - lm%d

11000

Jmox Compound nm

212 9900

205 12000

208 13500

I I 199 12000

I

d I 1: )

5 9600

10 1

13

275 1800

6 210

A question arose a t t h i s point a s t o whether the

mixtures generated above were i n f a c t equilibrium

mixtures or whether base abs t rac t ion of the C-8 proton

was merely slow. The observation of ident ical product

mixtures being formed w i t h i n 30 minutes when e i t h e r 1 0 or - 11 were used as the s t a r t i n g mater ia l confirmed tha t - abstract ion was rapid and complete. We repeated these

experiments on - 1 0 and 2 using E t O D a s the solvent and

examining the products by GC/MS. We had expected t o f ind

only the complete exchange of one proton b u t found tha t

i n addition t o t h i s - ca. 30% had exchanged a second proton

f o r deuterium. The only other act ivated methylene group

was the bridgehead posi t ion C 1 , a t o the carbonyl. We

were not able t o Find a c i d i t i e s of s imi la r systems i n the

l i t e r a t u r e but i t is kn0wn~313~ t h a t the a c i d i t i e s of

methylenes a t o n i t r i l e s a re comparable t o those a t o

carbonyls i n a l i p h a t i c compounds. I t has a lso been

reported t h a t act ivated methylenes a t bridgehead

posit ions have lower a c i d i t i e s than analogous

non-bridgehead methylenes because of hindrance t o

resonance s t a b i l i z a t i o n of the carbanion.

11 abstract ion of the proton a t C 1 was occurring upon

treatment w i t h sodium ethoxide, a l b e i t a t a slower ra te

than the abs t rac t ion a t C g . The lack of formation of new

c~mpounds on t rea tment w i t h sodium ethoxide a l so

supported our o r i g i n a l assignment of c i s fused r i ng - geometry f o r the adducts 10, and 11.

I r r a d i a t i o n of a - ch lo roac ry lon i t r i l e w i t h 6 i n - a c e t o n i t r i l e gave two adducts f o r which s t r u c t u r e s 1 2 and - 1 3 a r e suggested. I r r a d i a t i o n of a - ace toxyac ry lon i t r i l e - w i t h 6 i n a c e t o n i t r i l e gave two adducts f o r which - s t r u c t u r e 15 and 16 a r e suggested.

Scheme 12:

The a-chloro and a-acetoxy a c r y l o n i t r i l e adducts

(12,13f15f16) ---- were inseparable and IH and 13c NMR

analyses were done on mixtures. In a l l cases the s i g n a l s

due t o t h e proton a t C 1 appeared e i t h e r a s s i n g l e t s o r

mu l t i p l e t s w i t h small coupling constants i nd i ca t i ve of

lone range i n t e r a c t i o n s and incons i s ten t w i t h v i s c ina l C8

hydrogens. These s p e c t r a l c h a r a c t e r i s t i c s indica ted

B-regiochemistry f o r --- 12,13,15 and 16.

I t was n o t p o s s i b l e t o a s s i g n t h e geometry of t h e

r i n g f u s i o n by b a s e i s o m e r i z a t i o n e x p e r i m e n t s s i n c e m i l d

b a s e caused e x t e n s i v e d e c o m p o s i t i o n of these a d d u c t s .

Given t h e predominance o f - cis f u s e d b i c y c l o [ 4 . 2 . 0 l o c t y l

d e r i v a t i v e s from p h o t o a d d i t i o n s o f c y c l i c

a , B - u n s a t u r a t e d c a r b o n y l s and e l e c t r o n d e f i c i e n t

o l e f i n s l 2 r 4 l is it s u g g e s t e d t h a t a d d u c t s , --- 12,13,15 and

1 6 are c i s f u s e d . - - We were a b l e t o a s s i g n t h e s t e r e o c h e m i s t r y i n

12 ,13,15 and 1 6 by ana logy w i t h p r e v i o u s work i n t h e --- - s t e r o i d f i e l d 3 5 i n which t h e e f f e c t s o f s u b s t i t u e n t s i n

1 , 3 - d i a x i a l c o n f i g u r a t i o n s on t h e IH NMR chemical s h i f t s

of methyl r e s o n a n c e s were measured. I t was found t h a t

d e s h i e l d i n g of t h e methyl g r o u p and hence t h e magni tude

of t h e d o w n f i e l d s h i f t of t h e methy l r e s o n a n c e was i n t h e

o r d e r of Cl>CN>OAc>H.

We a l s o compared t h e 1 3 ~ c h e m i c a l s h i f t s of t h e

n i t r i l e i n t h e d i a s t e r e o m e r s -- 12:13 and 15:16.

Examinat ion of models s u g g e s t e d t h a t n i t r i l e s i n t h e endo

c o n f i g u r a t i o n were i n t h e s h i e l d i n g z o n e s of

t h e l a c t o n e c a r b o n y l s . Hence t h e 1 3 ~ ~ r e s o n a n c e s of

a d d u c t s p o s s e s s i n g t h e endo n i t r i l e c o n f i g u r a t i o n would

be e x p e c t e d a t h i g h e r f i e l d s r e l a t i v e t o t h o s e w i t h

n i t r i l e s i n t h e - e x o c o n f i g u r a t i o n s . S i m i l a r e f f e c t s have

been p r e v i o u s l y used t o a s s i g n s t e r e o ~ h e m i s t r ~ ~ ~ . The

experimentally observed chemical s h i f t s and subsequent

s t ruc tu re assignment a re l i s t e d i n Table 4 . The

stereochemical ass ignments conducted on t h i s basis were

e n t i r e l y consis tent w i t h assignments- made by

considerat ion of v i c ina l coupling constants and base

equi l ib ra t ion experiments.

. I r rad ia t ion of a c r y l o n i t r i l e , a-chloroacrylonit r i l e

and a-acetoxyacrylonitr i le w i t h - 7 each gave s e t s of two

adducts (lJ:_18; =:20; 2:z respectively) which were

inseparable except by c a p i l l a r y gas chromatography.

GC/MS spec t ra l ana lys i s were consis tent w i t h formation of

[ 2 + 2 ] cycloadducts i n each reaction. Both

6-regiochemistry and - c i s r ing fusion were assumed f o r

these adducts . The n i t r i l e stereochemistry assigned was

deduced fqom the arguments given above pertaining t o

Table 4 .

Scheme 13:

Table 4 : 'H and NMR Chemical Shif tg

Compound

Structure

Ra - CN

H

CI

CN

CN

OAc

CN

H

CN

CI

0 Ac

CN -

It RI - ti

CN

CN

CI

DAc

CN

H CN

CI

CN

CN

OAc -

Figure 6: Bicyclic Numbering System

-27- --

The mix tu res of the 2 photoadducts - 17 and -I 18 from

t h e pho toadd i t ions of 2-pentenolide (2) t o a c r y l o n i t r i l e

were a l s o s u b j e c t e d t o base e q u i l i b r a t i o n with NaOEt.

This mixture was found t o r a p i d l y i somer ize t o a 75:25

mixture of -- 17:18 a t 25%. This r a t i o was a l s o i n good

agreemdnt w i t h t h e p red ic ted (Table 3 ) r a t i o of 71:29

exo:endo whaich suggested t h a t 17 possessed the exo-CN -- - s t e r e o c h e m i s t r g whi le - 18 was - endo-CN.

Some o b s e r v a t i o n s on t h e s t e r e o s e l e c t i v i t y of t h e

photocycloaddi t ion reac t ions of t h e 6- lactones - 6 and - 7

can be made. The r a t i o s of the - exo-CN t o - endo-CN,

6-regioisomers, 10:11, 13:12, 15:16, 17:18, 19:20 and -7 -- -7 -- --

22:21, produced were found t o be i n s e n s i t i v e t o t h e -- -

temperature (Tab le 1). T h i s r a t i o was a l s o r e l a t i v e l y

i n s e n s i t i v e t o s u b s t i t u t i o n a t C-6 (CH3 vs HI. The

adducts were found t o be pho tos tab le and t h e r a t i o s

observed a r e n o t due t o photoisomerizat ion.

We next turned our a t t e n t i o n ts photocycloaddi t ion

of t h e Y -1actone - 8 and found s e v e r a l notable d i f f e r e n c e s .

We found t h a t i r r a d i a t i o n of w i t h a c r y l o n i t r i l e i n

a c e t o n i t r i l e produced four isomeric 1 : l* adducts, - 23, - 2 4 ,

25 and 26 (Table 5 ) . - - Scheme 14:

- Table 5 : Summary of Reactions of I'-Lactones

endo-CN Undetermined TProdust % Products

38 24,26 22,17 42 24,26 19,15

15 27,29 27,32 20 27.29 19,25

exo-CN yield% Product %

29 23 23 40 - 23 23

- - - 78 28 26 81 . 28 35 - - - -

Experimenl GI G2 HI H2 .

- I1 I2 J 1 52 K1 K2 L1 L2

H H C I CI

OAc OAc H H C1 C1 3Ac 3Ac -

Table 6: Summary of MM2 Calculations f o r )?-Lactones

trans

Strain - Strain trans Energy

Isomer K J ~ -

40 228.0

41 217.5 42 227.9

43 225.0

44 163.0

45 268.3

46 272.4

47 269.8

a. Coupling Constant J Calculated from ~ i h e d t a l 'Angle (-1 by ~ a r ~ l u s ~ ' Equation i n the form; J= A + ~ ~ o s f l + CcosZH

where A=7, B=-1 , CIS. . .

T h i s m i x t u r e was p a r t i a l l y s e p a r a t e d i n t o two f r a c t i o n s

e a c h c o n t a i n i n g a pa i r of p r o d u c t s . W e de te rmined t h a t

t h e s e p r o d u c t s were n o t t h e i s o m e r i c o x e t a n e s nor

e x o c y c l i c o l e f i n s by GC/MS and 13c NMR a n a l y s i s . We a l s o

d e t e r m i n e d t h a t t h e i s o l a t e d p h o t o a d d u c t s -- 23-26 and were

n o t a f f e c t e d by t r e a t m e n t w i t h a lumina . From t h e s e

e x p e r i m e n t s we deduced t h a t p h o t o a d d u c t s 23-2 and

p o s s e s s e d t h e more s t a b l e cis r i n g f u s i o n . The

p o s s i b i l i t y of i s o l a t i n g t r a n s f u s e d [ 2 + 2 ]

p h o t o c y c l o a d d u c t s from t h e i r r a d i a t i o n of Y - 1 a c t o n e s

w i t h a c r y l o n i t r i l e was c o n s i d e r e d u n l i k e l y i n view of t h e

l a c k of any l i t e r a t u r e p r e c e d e n t .

We c o n c l u d e d p r o d u c t s 23-26 were a m i x t u r e of t h e

exo-CN and endo-CN, B and Y - r e g i o i s s m e r s . T h i s was not - e n t i r e l y u n e x p e c t e d as p r e v i o u s workers had r e p o r t e d t h a t

5-membered c y c l i c e n o n e s and l a c t o n e s were more p rone t o

g i v e m i x t u r e s of r e g i o i s o m e r s t h a n t h e i r 6-membered r i n g

ana logs12 ,20 . S i n g l e c r y s t a l s of 23 and 25 were i s o l a t e d

from t h e m i x t u r e s and unambiguously i d e n t i f i e d by X-ray

c r y s t a l a n a l y s i s a s t h e - cis f u s e d , 6 , - exo-CN isomer and

c i s f u s e d , B , endo-CN i somer r e s p e c t i v e l y 3 g . We assumed - t h a t a d d u c t s - 24 and - 26 were t h e Y- reg io i somers ( d e p i c t e d

a s - 35 and - 36 i n T a b l e 6 ) b u t c o u l d n o t show t h i s by

e i t h e r 1~ o r 1 3 ~ NMR a n a l y s i s because of o v e r l a p p i n g

s i g n a l s .

Treatment of t h e p h o t o l y s i s mixture (23-26) w i t h -- sodium e thox ide a s before r e s u l t e d i n conversion t o

h igh ly p o l a r compounds, presumably by t r a n s e s t e r i f i c a t i o n

of t h e l a c t o n e . The r a t i o of photoadducts 23-26 was -- found t o be s l i g h t l y s e n s i t i v e t o t h e temperature of t h e

pho to reac t ion and the i s o l a t e d adduc t s were found t o be

pho tos tab le (Table 5 ) .

I r r a d i a t i o n of a-chloro o r a -ace toxyacry lon i t r i l e

w i t h - 8 i n a c e t o n i t r i l e gave no photoadducts. Presence of

e i t h e r of t h e s e two o l e f i n s i n t h e r e a c t i o n mixture a l s o

prevented r e a c t i o n between t h e - 8 and a c r y l o n i t r i l e . T h i s

is probably due t o over lap of t h e absorp t ion bands of t h e

Y-lactones w i t h t h e heteroatom-subst i tuted

a c r y l o n i t r i l e s (Table 7 ) . S ince t h e o le f i n s were p resen t

i n t en fo ld excess these would block absorbance by t h e

l ac tone . In an at tempt t o circumvent t h i s problem we

slowly added t h e a c r y l o n i t r i l e d e r i v a t i v e s t o the

s o l u t i o n of l a c t o n e - 8 during t h e i r r a d i a t i o n . We

reasoned t h a t i f t he concen t ra t ion of t h e o l e f i n was kept

low then it would not i n t e r f e r e w i t h t h e t ransmission of

l i g h t i n t h e s o l u t i o n . T h i s technique was not

s a t i s f a c t o r y and only produced t r a c e amounts of t h e

d e s i r e d 1:l photoadducts which were t e n t a t i v e l y

i d e n t i f i e d by t h e i r MS.

Because we were t r y i n g t o extend the s y n t h e t i c

u t i ' l i t y of t h e s e r eac t ions we considered the production

of mixtures of regioisomers t o be unacceptable and

attempted t o a l t e r t h e r e g i o s e l e c t i v i t y of t h e reac t ion .

We reasoned t h a t the i nc lu s ion of methyl groups a t C3 and

Cq i n a Y- lac tone would impede t he formation of

Y-regioisomers. Accordingly we undertook the syn thes i s

of the methyl s u b s t i t u t e d Y -1actone 9 by the route shown

i n Scheme 16 and i nves t i ga t ed its photochemistry.

I r r a d i a t i o n of - 9 w i t h a c r y l o n i t r i l e i n a c e t o n i t r i l e

produced four isomeric 1:l photoadducts, - 27 , - 28 , - 29 and

30. These compounds were unaffected by treatment w i t h 7

alumina i nd i ca t i ng t h a t they a l l possessed a r ing

fus ion. Repeated chromatography on s i l i c a ge l eventual ly

separa ted the minor component - 30 from t h e mixture.

Scheme 15:

The B -regiochemistry of the n i t r i l e i n a was

evident from t h e s p l i t t i n g p a t t e r n of the s i g n a l due t o

H i i n the 18 nmr spectrum of t h i s compound. We

t e n t a t i v e l y assigned t he - endo stereochemistry t o the

n i t r i l e of - 30 a f t e r comparison of the experimental ly

observed coupling constant of H i - H 7 (8 .5 Hz) t o e a r l i e r

$=heme 16: synthes i s of 3,4,4-trimethyl-2-butenolide

r e p o r t s of c o u p l i n g c o n s t a n t s i n s i m i l a r - c i s - f u s e d

b i c y c l o t 3 . 2 . 0 1 h e ~ t a n o n e s ~ ~ . Kosugi had r e p o r t e d t h a t f o r

s u c h f u s e d s y s t e m s t h e - cis H i - H q c o u p l i n g was 9.0 H z and

t h e t r a n s H i - H 7 c o u p l i n g was 5 .1 H z . T h i s is i n

modera te ly good agreement w i t h o u r M M 2 d e r i v e d c o u p l i n g

c o n s t a n t s 3 8 of Jcis = 10.9 H z and Jtrans = 3.2 H Z f o r - 30

and - 37 r e s p e c t i v e l y .

The o t h e r t h r e e components o f t h e m i x t u r e were

i n s e p a r a b l e by chromatography and s p e c t r a l a n a l y s e s were

performed on t h e m i x t u r e . Due t o t h e complex i ty of t h e

1~ nmr spectra of t h i s m i x t u r e w e were u n a b l e t o a s s i g n

t h e r e g i o o r s t e r e o c h e m i s t r y of -- 27-29. W e assumed t h e

m i x t u r e c o n s i s t e d of t h e - exo-CN 0 - r e g i o a d d u c t and t h e

e x o and endo-CN Y - r e g i o a d d u c t s i l l u s t r a t e d as 37, 38, and - - - 39 r e s p e c t i v e l y i n Tab le 6. -

Thus w e were u n a b l e t o make any d e f i n i t i v e

s t a t e m e n t s c o n c e r n i n g t h e e f f e c t s o f me thy l v s hydrogren

s u b s t i t u t i o n a t C 3 and C4 i n t h e p a r e n t l a c t o n e s on t h e

r e g i o s e l e c t i v i t y of t h e p h o t o a d d i t i o n . I t was a p p a r e n t ,

however, t h a t t h e r e was no s i g n i f i c a n t improvement i n t h e

r e g i o s e l e c t i v i t y of p h o t o a d d i t i o n upon methyl

s u b s t i t u t i o n .

The e f f ec t of t e m p e r a t u r e on t h e p r o d u c t

d i s t r i b u t i o n was a l s o examined f o r t h e r e a c t i o n of - 9 w i t h

a c r y l o n i t r i l e ( T a b l e 5 ) . The r a t i o of -- 27-30 was found t o

be s l i g h t l y a f f e c t e d by t h e t e m p e r a t u r e a t which t h e

i r r a d i a t i o n was c o n d u c t e d . D e c r e a s i n g t h e t e m p e r a t u r e

from a m b i e n t t o -200C i n c r e a s e d t h e r e l a t i v e amount of 30 - by 5%. The r e l a t i v e amounts o f 2-2 a l s o changed by

709%. While t h i s change is small it was t h e la rges t

change i n p r o d u c t d i s t r i b u t i o n d u e t o t e m p e r a t u r e

obse rved i n t h i s work.

I t s h o u l d b e n o t e d t h a t a lesser change i n t h e

p r o d u c t d i s t r i b u t i o n of t h e 1:l c y c l o a d d u c t s d u e t o

t e m p e r a t u r e was a l s o o b s e r v e d i n t h e p h o t o a d d i t i o n of

a c r y l o n i t r i l e t o t h e hydrogen s u b s t i t u t e d Y -1ac tone 8. - I n t h e s e p h o t o a d d i t i o n s ( e x p e r i m e n t s G 1 and G 2 , Table 5 )

it was f o u n d t h a t t h e r e l a t i v e amount o f t h e e n d o - n i t r i l e 6 - r e g i o i s o m e r , - 25, i n c r e a s e d by 4% and t h e e x o - n i t r i l e 8 - r e g i o i s o m e r , 23, d i d n o t change when t h e

t e m p e r a t u r e was lowered f rom a m b i e n t t o - 2 0 0 ~ . The

r e l a t i v e amounts o f t h e two Y - r e g i o a d d u c t s - 24 and - 26

( i l l u s t r a t e d as 35 and 36 i n T a b l e 5 ) d e c r e a s e d by

2-3% when t h e t e m p e r a t u r e was lowered f rom ambien t t o

-20•‹C. T h i s e f fec t was c o n s i s t e n t w i t h t h e simple d i p o l e

i n t e r a c t i o n model p roposed by c o r e y 1 2 , which would f a v o u r

. \ t h e f o r m a t i o n o f t h e 8 - r e g i o a d d u c t s a t l o w e r

t e m p e r a t u r e s . T h i s r a t i o n a l i z a t i o n is p r e d i c a t e d on t h e

c h a r g e d i s t r i b u t i o n i n t h e e x c i t e d s t a t e Y - l a c t o n e b e i n g

r e v e r s e d t o t h a t o f t h e ground s t a t e l a c t o n e .

We u t i l i z e d t h e p r e f e r e n t i a l f o r m a t i o n of t h e

B-regiosomers a t l o w e r t e m p e r a t u r e s t o a s s i g n t h e

r e g i o c h e m i s t r y of a d d u c t s 27-z ( e x p e r i m e n t s J1 and 3 2 ,

T a b l e 5 ) . T h i s l i n e of r e a s o n i n g s u g g e s t e d t h a t 28 was

t h e - e x o n i t r i l e B - r e g i o a d d u c t (37, T a b l e 6 ) as t h e

r e l a t i v e amount i n c r e a s e d by 9% o n r e d u c t i o n of t h e

t e m p e r a t u r e from a m b i e n t t o -20•‹c. The r e l a t i v e amounts

of - 27 and - 29 d e c r e a s e d by 7% e a c h a t lower t e m p e r a t u r e s

s u g g e s t i n g t h a t t h e s e two a d d u c t s were t h e

Y - r e g i o i s o m e r s ( i l l u s t r a t e d as - 38 and 2 i n T a b l e 6 ) .

I n summary it was f o u n d t h a t a c e t o n i t r i l e s o l u t i o n s

of t h e 6 - 1 a c t o n e s - 6 and - 7 underwent [2+21

p h o t o c y c l o a d d i t i o n w i t h a c r y l o n i t r i l e and i ts a - c h l o r o

and a - a c e t o x y d e r i v a t i v e s i n a h i g h l y r e g i o s e l e c t i v e

manner t o g i v e m i x t u r e s of - e n d o - n i t r i l e and - e x o - n i t r i l e

B- reg ioadduc t s . The y i e l d s of t h e s e r e a c t i o n s ranged

f rom good t o m o d e r a t e and none o f t h e Y - r e g i o i s o m e r s were

i s o l a t e d . The B - r e g i o a d d u c t s were o f t e n i s o l a t e d i n a

c r y s t a l l i n e fo rm which a l l o w e d r e c r y s t a l l i z a t i o n t o a

h i g h d e g r e e o f p u r i t y .

The s t e r e o c h e m i s t r y a t C8 i n t h e p h o t o a d d u c t s was

found t o be i n s e n s i t i v e t o e i t h e r t h e s u b s t i t u t i o n a t

C 3 (CH3 v s H) i n t h e p a r e n t l a c t o n e s o r t h e t e m p e r a t u r e

a t which t h e i r r a d i a t i o n was c o n d u c t e d . D e s p i t e t h e l a c k

o f c o n t r o l of t h e C 8 s t e r e o c h e m i s t r y t h e h i g h r e g i o -

s e l e c t i v i t y of t h e s e r e a c t i o n s s h o u l d be of some

s y n t h e t i c u t i l i t y .

The Y- lac tones - 8 and - 9 d i d n o t undergo photo-

a d d i t i o n w i t h a - ch lo ro o r a - a c e t o x y a c ~ y l o n i t r i l e ,

presumably due t o o v e r l a p of t h e a b s o r p t i o n bands of t h e

o l e f i n s and t h e l a c t o n e s .

The Y- lac tones - 8 and - 9 d i d undergo photoaddi t ion

w i t h a c r y l o n i t r i l e i n a c e t o n i t r i l e s o l u t i o n s i n an

e f f i c i e n t manner, bu t w i t h poor r e g i o s e l e c t i v i t y . The

hydrogen s u b s t i t u t e d Y -1actone - 8 produced a 3:2 mixture

of B : Y - reg io i somers a t ambient t empera tu re and a

m a r g i n a l l y h i g h e r p r o p o r t i o n of 6-regioadducts a t -20•‹C.

The methyl s u b s t i t u t e d Y -1actone - 9 produced a 2: 3 mixture

of B : Y - reg ioadduc ts a t ambient t empera ture and a

s l i g h t l y h i g h e r p r o p o r t i o n of t h e d e s i r e d

B-regioadduct a t -20%.

The poor r e g i o s e l e c t i v i t y e x h i b i t e d by the

Y- lac tones 8 and 9 and t h e d i f f i c u l t y of s e p a r a t i n g t h e

B and Y r eg ioadduc t s produced, c u r t a i l t h e s y n t h e t i c

u t i l i t y of t h e s e r e a c t i o n s c o n s i d e r a b l y .

EXPERIMENTAL

Infrared spectra were recorded on a Perkin-Elmer 5958

spectrophotometer a s l iqu id f i l m s between NaCl p la tes or

as KBr p e l l e t s . Ul t rav io le t spectra were recorded on a

Unicam SP 800 spectrophotometer. Nuclear magnetic

resonance spectra were recorded on a Bruker 400 WM NMR

spectrometer using C D C 1 3 a s a solvent and the residual

CHC13 as an in t e rna l standard. The chemical s h i f t s a re

reported i n 6 u n i t s , the s p l i t t i n g pa t te rns as

s ( s i n g l e t ) , d (double t ) , t r ( t r i p l e t ) , q ( q u a r t e t ) ,

dd (double doublet) , m (mul t ip le t ) . coupling constants

(J) are reported i n Hz (cycles /sec) . I n l 3 ~ analysis the

m u l t i p l i c i t i e s were determined by 9 modulated spin echo

experiments (mulipl ic i ty s o r t i n g ) . Low resolution mass

spectra were obtained on a Hewlett-Packard 59858 coupled

gas chromatograph/mass spectrometer u s i n g an e lectron

impact ionization voltage of 70 eV. Melting points were

' determined on e i t h e r a Fisher-Johns hot p la te or a

Gallenkamp melting point apparatus and are uncorrected.

Boiling points a re not corrected. GLC analyses were

obtained on a Hewlett-Packard 5880A gas chromatograph

equipped w i t h a flame ionizat ion detector and u s i n g a

0.2 mm I D x 15 m O V - 1 0 1 o r a DB-1 cap i l la ry column.

Elemental analyses were performed by M . K . Yang a t the

Department of Biological Sciences, S.F.U.

A l l photolyses, except f o r those experiments

concerned w i t h solvent e f f e c t s were run i n HPLC grade

a c e t o n i t r i l e obtained from Caledon Laboratories.

( d l ) Mevalonalactone was obtained from Sigma,

a c r y l o n i t r i l e , a -chloroacryloni t r i le and

5-hydroxy-2-pentenoiclactone (1) from Aldrich Chemical

Co, , and a -acetoxyacrylonit r i l e from Alpha Chemical Co.

General Procedure of Photoaddition

The lactones and o le f ins were d i s t i l l e d before use.

HPLC grade a c e t o n i t r i l e was used without pur i f icat ion. I n

a typical experiment a so lu t ion of the lactone (ca. - 40 mmol), o l e f i n (5-10 eq) and an in t e rna l standard ( a

sa turated hydrocarbon such a s decane) i n z. 200 mL

a c e t o n i t r i l e was placed i n a Pyrex, quartz or Vycor

photolysis apparatus equipped w i t h a reflux condenser

( F i g . 7 ) . The so lu t ion was deoxygenated by purging w i t h

N2 f o r 30 minutes before ac t iva t ing the lamp. For low

temperature experiments the apparatus was cooled i n an

acetone/C02 bath i n a Dewar f lask . A 450 W Hanovia 6790A

medium pressure mercury lamp enclosed by a quartz water

cooled lamp jacket was used fo r the i r rad ia t ions , 1

The reactions were followed by periodically removing

al iquots during the i r r ad ia t ion and subjecting them t o GLC

analysis . I r r ad ia t ion was stopped when there was no

Figure 7 : Photolysis Apparatus

Condensor Adapter

Lamp Well

Solution Compartment

Immersion Well

Torus Reactor

f u r t h e r change of t h e c o n c e n t r a t i o n s o f e i t h e r t h e

s t a r t i n g l a c t o n e o r p r o d u c t s r e l a t i v e t o t h e i n t e r n a l

s t a n d a r d . The i n i t i a l (T=O) s a m p l e was k e p t i n t h e d a r k

as a c o n t r o l and a n a l y z e d a g a i n a t t h e end of t h e p h o t o

e x p e r i m e n t . None o f t h e c o n t r o l s o l u t i o n s showed s i g n s o f

t h e r m a l r e a c t i o n . I s o l a t i o n of t h e p r o d u c t s i n v o l v e d

t r e a t m e n t o f t h e s o l u t i o n w i t h a c t i v a t e d c h a r c o a l and

b o i l i n g f o r 1 0 min. f o l l o w e d by g r a v i t y f i l t r a t i o n . A f t e r

c o o l i n g t h e s o l u t i o n was c o n c e n t r a t e d i n vacuo and t h e

r e s u l t i n g v i s c o u s o i l was t r e a t e d w i t h - c a . 50 mL MeOH and

f i l t e r e d t h r o u g h C e l i t e t o remove p o l y m e r i c b y p r o d u c t s .

T h i s s o l u t i o n was c o n c e n t r a t e d i n vacuo and t h e r e s i d u e

was d i s t i l l e d i n a K u g e l r o h r a p p a r a t u s t o y i e l d t h e c r u d e

p h o t o a d d u c t s . A n a l y t i c a l s a m p l e s were p u r i f i e d by f l a s h

chromatography o n s i l i c a g e l and c r y s t a l l i n e compounds

were r e c r y s t a l l i z e d f rom a s u i t a b l e s o l v e n t .

P r e p a r a t i o n o f Anhydromeva lono lac tone ( 6 )

( d l ) Meva lon ic l a c t o n e was d e h y d r a t e d and i s o m e r i z e d

by t h e method of sum8 t o g i v e a 78% y i e l d of d i s t i l l e d

a n h y d r o m e v a l o n o l a c t o n e , b o p . 85 -86O~/2 t o r r it* b o p .

7 4 - 7 6 0 ~ / . 9 t o r r ) , which was 99% p u r e by GLC; i r ( f i 1 m ) :

1 7 2 0 ( s ) , 1 6 4 0 ( m ) , 1400(m) , 1380(m) , 1310(m) , 1270(m) ,

1 2 2 5 ( s ) , 1 1 5 5 ( w ) , lOgO(w), 1 0 7 0 ( m ) , 1 0 0 0 ( w ) , 855(m) cm-1;

l H nmr(CDCl3)g: 1 . 8 7 ( 3 H , s ) , 2.25(2H, t r , 517 Hz), 4 .23(2Ht

tr, 5x7 Hz), 5.62(1Hf br s); uv(CH3CN):Xmax = 212 nm, =

9900 lm'lcm-1; ms(E1): 112(54, Mt), 82(100), 72(10),

Lactone - 6 was also prepared in 65% yield from

4-hydroxy-2-butanone by the procedure of White et a16 and

gave identical spectral data.

Preparation of 2-butenolide (8)

Lactone - 8 was prepared by a published method37 to give a 31% yield of - 8 which was 96% pure by GLC, bop. 95-980~/15 torr ( ~ i t 3 7 b.p. 10g0c/24 torr); ir(fi1m) :

1750(s), 1600(w), 1450(m), 1350(m), 1330(m), 1160(s),

1095(m), 1035(m), 890(m), 815(m) cm-l; IH nmr ( c D c ~ ~ ) ~ :

4.82(2Hf dd, J=2Hzf ~Hz), 6.02(1Hf dt, J=6Hzf 2Hz),

7.75(1Hf dt, J=6Hz, 3Hz); U V ( C H ~ C N ) : X ~ ~ X = 205 nm,

E = 12000 lm-1 cm-1; ms(C1, isobutane): 85(100, Mtl)

Preparation of 3,4,4-trimethyl-2-buten-1,4-olide (9)

a) 2,3-epoxy-2-methylbutane:

To a solution of 20.1 g(117 mmol, 1.0 eq) mCPBA in

200 mL freshly distilled diphenyl ether (bop. 121-122•‹C/10

Corr) was added dropwise 9.7 g(138 mmol, 1.2 eq) 2-methyl-

2-butene over 1 hr maintaining the temperature at 25-30•‹c

with an ice/water bath. After the addition the cold bath

was removed and the mixture stirred at room temperature

f o r 1 h r and t h e n a C02/acetone c o l d t r a p was a t t a c h e d t o

t h e f l a s k and t h e v o l a t i l e s drawn o u t o f t h e m i x t u r e w i t h

a n a s p i r a t o r vacuum (s. 20 t o r r ) f o r 1 h r . T h i s was

f o l l o w e d by mechan ica l pump e v a c u a t i o n ( c a . 5 t o r r ) f o r 1 2 - h r . The c o l d t r a p p e d v o l a t i l e s c o n t a i n i n g t h e u n r e a c t e d

s t a r t i n g material and t h e d e s i r e d e p o x i d e were t h e n

c a r e f u l l y f r a c t i o n a t e d t h r o u g h a 1 5 cm Vigreaux column a t

a t m o s p h e r i c p r e s s u r e . The f r a c t i o n b o i l i n g a t 70-73% was

c o l l e c t e d y i e l d i n g 5.65 g ( 5 6 % ) o f 2,3-epoxy-2-methylbutane

which was 95% p u r e by GLC; IH nmr(CDC13, 60 M H z ) S :

1.1(9H, b r m ) , 2.8(1Hr q , J=6 Hz).

b) 3,4,4-trimethylbutan-1,4-olide:

To 50 mL anhyd. e t h a n o l ( d i s t i l l e d from Mg) under

a r g o n a tmosphere was added 1 .29g(56 .3 mmol, 1.1 e q ) of

sodium metal. When t h e e v o l u t i o n of H2 ceased 8.59g(53.7

m m o l , 1 . 0 eq) d i e t h y l m a l o n a t e was added i n one p o r t i o n and

t h e m i x t u r e h e a t e d t o r e f l u x f o r 1 0 min. A s o l u t i o n o f

4 .40 g ( 5 1 . 1 mmol, 1 .0 e q ) o f 2,3-epoxy-2-methylbutane i n 5

mL anhyd. e t h a n o l was added t o t h e r e f l u x i n g m i x t u r e o v e r

1 h r and t h e r e s u l t i n g m i x t u r e was r e f l u x e d f o r 64 h r a t

which p o i n t GLC a n a l y s i s r e v e a l e d no f u r t h e r change i n t h e

- r e l a t i v e amount of s t a r t i n g m a t e r i a l . Heat ing was

d i s c o n t i n u e d and 2.15 g ( 5 3 . 7 mmol, 1 .05 e q ) NaOH i n 70 mL

Hz0 was added. The condense r was reset f o r downward

d i s t i l l a t i o n and t h e t h e o r e t i c a l amount of e t h a n o l removed

by d i s t i l l a t i o n . The r e s i d u e was c o o l e d t o 5% and

c a r e f u l l y a c i d i f i e d t o pH 2 w i t h c o n c e n t r a t e d HC1. T h i s

m i x t u r e was t h e n e x t r a c t e d w i t h 5 x 50 mL CH2C12. The

combined o r g a n i c ex t rac ts were d r i e d o v e r anhyd. MgS04,

f i l t e r e d and c o n c e n t r a t e d i n vacuo l e a v i n g 6.11 g . of a

w h i t e c r y s t a l l i n e mass, mop. 95-100•‹C. T h i s material was

h e a t e d i n a n o i l b a t h a t 130% t o i n d u c e d e c a r b o x y l a t i o n .

When t h e e v o l u t i o n o f C02 had c e a s e d t h e r e s i d u e was

c o o l e d and t h e n d i s t i l l e d t o y i e l d 4.22 g ( 6 5 % ) o f t h e

t i t l e compound, b o p . 1 2 4 - 1 2 6 0 ~ / 2 0 t o r r which was 98% p u r e

To a s o l u t i o n o f 30.8 mmol( l .2 e q ) LDA i n 200 mL

anhyd. THF ( p r e p a r e d i n t h e u s u a l way f rom 3.12 g

d i i s o p r o p y l a m i n e and 13 .9 mL 2.3 M n-BuLi) under Argon

a tmosphere a t -78% was added 3.29 g ( 2 5 . 7 m m o l , 1 .0 e q )

2,3-dimethylbutan-l,4-olide i n 70 mL THF over 20 min. The

r e s u l t i n g y e l l o w s o l u t i o n was s t i r r e d a t -78% f o r 1 h r

and t h e n a s o l u t i o n o f 6.39 g ( 3 3 . 4 mmol, 1 . 3 e q ) f8SeC1 and

5.06 g (28 .2 mmol, 1.1 e q ) HMPA i n 70 mL THF was added t o

t h e s t i r r e d e n o l a t e s o l u t i o n o v e r 1 0 min. The f8SeC1

s o l u t i o n was d e c o l o r i z e d immedia te ly on mixing . T h i s

s o l u t i o n was s t i r r e d a t -78% f o r 1 h r , t h e n warmed t o

room t e m p e r a t u r e and poured i n t o a c o l d aqueous s o l u t i o n

of NH4C1 and e x t r a c t e d w i t h 3 x 50 mL E t O A c . Combined

o r g a n i c ex t rac ts were washed w i t h 30 mL s a t . NaHC03, d r i e d

o v e r anhyd. MgS04 and f i l t e r e d . The clear y e l l o w f i l t r a t e

was t r e a t e d w i t h 6.7 mL(51.4 mmol, 2.0 e q ) 40% p e r a c e t i c

a c i d and t h e r e s u l t i n g t u r b i d w h i t e m i x t u r e was s t i r r e d a t

room t e m p e r a t u r e f o r 2 h r , t h e n p o u r e d i n t o 1 0 0 mL o f ice

water. The l a y e r s were s e p a r a t e d a n d t h e o r g a n i c l a y e r

was washed w i t h 30 mL 1 0 % NaHC03, 30 mL 1 0 % NaHS03,50 mL

s a t . NaC1, d r i e d o v e r anhyd. MgS04, f i l t e r e d and

c o n c e n t r a t e d i n vacuo . The r e s i d u e was d i s t i l l e d t o y i e l d

2.33 g ( 7 2 % ) of 2, b o p . 9 2 - 9 5 0 ~ / 1 0 t o r r which was 98% p u r e

by GLC; i r ( f i 1 m ) : l 7 5 O ( s ) , 1650(m) , 1 4 4 0 ( w ) , 1 3 9 0 ( w ) ,

1 3 2 0 ( w ) , 1 2 5 0 ( m ) , 1 1 8 0 ( m ) , 1 0 9 0 ( w ) , 9 7 5 ( m ) t 945(m) t

875(w)cm-1: 1~ nmr(CDCl3) 6 : 1.42(6H, s), 2 . 0 3 0 8 , d ,

13500 lm' lcm' l ; m s ( E 1 ) : 1 2 6 ( 5 , M t ) , 1 1 1 ( 2 0 ) , 8 3 ( 2 3 ) ,

6 8 ( l 2 ) , 5 5 ( 8 ) , 43 (1001 .

Anal . C a l c d . f o r C7H1002: C, 66.64; H , 7.99.

Found: C, 66.70; H , 8.01.

A. P h o t o a d d i t i o n of Anhydromeva lono lac tone ( 6 ) t o

A c r y l o n i t r i l e

1. Ambient T e m p e r a t u r e P h o t o l y s i s

A s o l u t i o n o f 0.447 g ( 3 . 9 8 mmol, 1 .0 e q ) 5 , 2.10

mL(31.8 mmol, 8.0 e q ) a c r y l o n i t r i l e and 0.107 g undecane

( i n t e r n a l s t a n d a r d ) i n 200 mL a c e t o n i t r i l e was p l a c e d i n a

Pyrex immersion w e l l . T h i s s o l u t i o n was i r r a d i a t e d

t h r o u g h a Vycor f i l t e r and t h e r e a c t i o n fo l lowed by GLC

a n a l y s i s of a l i q u o t s removed a t r e g u l a r i n t e r v a l s . The

t e m p e r a t u r e of t h e s o l u t i o n was moni to red and it

s t a b i l i z e d a t 35-40% a f t e r 0.5 h r of i r r a d i a t i o n . GLC

a n a l y s i s r e v e a l e d a l l t h e s t a r t i n g l a c t o n e had been

consumed a f t e r 1 . 5 h r and two h i g h e r b o i l i n g p r o d u c t s were

p r e s e n t . The i n i t i a l (time=O) sample k e p t i n t h e d a r k

showed o n l y t h e s t a r t i n g m a t e r i a l and i n t e r n a l s t a n d a r d

p r e s e n t by GLC. The u s u a l workup f o l l o w e d by s h o r t p a t h

d i s t i l l a t i o n a t a n oven t e m p e r a t u r e of 90-1100~/0 .1 t o r r ,

y i e l d e d 0.534 g ( 7 7 % ) of a c o l o r l e s s o i l which GLC a n a l y s i s

showed t o be m a i n l y t h e two h i g h e r b o i l i n g p h o t o a d d u c t s - 1 0

and - 11 i n t h e r a t i o of 57:43 i n o r d e r of i n c r e a s i n g

r e t e n t i o n time. The r a t i o between t h e two p r o d u c t s was

obse rved t o be c o n s t a n t t h r o u g h o u t t h e i r r a d i a t i o n . A

p o r t i o n o f t h e m i x t u r e (0.412 g ) was s e p a r a t e d by repeated'

f l a s h chromatography on s i l i c a g e l ( 4 0 g ) u s i n g 4 : l

E t 2 O : E t O A c a s t h e e l u a n t . F r a c t i o n s c o n t a i n i n g main ly t h e /

f a s t e r e l u t i n g component were i s o l a t e d a s a n o i l which

c r y s t a l l i z e d on s t a n d i n g . ~ e c r y s t a l l i z a t i o n twice from

E t O H gave 0.178 g ( 2 7 % ) of a w h i t e c r y s t a l l i n e compound,

m.p. 77.5-79.50C which was shown t o be t h e minor , s l o w e r

e l u t i n g component 11 by GLC. The major component - 1 0 was

i s o l a t e d a s a n o i l , 0.224 g ( 3 3 % ) , which d i d n o t

crystallize. The material was 93% pure by GLC, the

remainder being predominantly - 11. The regio and

stereochemistry of the photoadducts were assigned from

analysis of 1~ nmr spectra and base isomerization

experiments as described in the results.

exo-8-~yano-6-methyl-3-oxabicyclo[4.2.0]octan-2-one - (10); - ir (KBr pellet): 2240(w), 1730(~), 1400(m) 1380(~),

1280(m), 1220(m), 1070(m), 900(m) cm-l; 1~ nmr(CDC1316:

4.52(2H, Cq, m); 1% nmr 6: 168.82(C=O), 119.15(CN),

2. Low T e m p e r a t u r e P h o t o l y s i s

A s o l u t i o n o f 0.402 g ( 3 . 5 8 m m o l , 1 . 0 e q ) 6,

1 .53 g ( 2 8 . 8 m m o l , 8 .0 e q ) a c r y l o n i t r i l e and 0.082 g

undecane i n 1 5 0 mL a c e t o n i t r i l e was p l a c e d i n a Pyrex

immersion well and t h e e n t i r e a p p a r a t u s p l a c e d i n a Dewar

f l a s k and c o o l e d t o - 4 0 0 ~ w i t h a n ace tone/C02 b a t h . Upon

i r r a d i a t i o n t h r o u g h a Vycor f i l t e r t h e t e m p e r a t u r e

s t a b i l i z e d a t - 2 0 0 ~ . GLC a n a l y s i s o f a l i q u o t s wi thdrawn

d u r i n g t h e c o u r s e of t h e i r r a d i a t i o n showed t h e l a c t o n e

had been consumed w i t h i n 2 h r . The u s u a l workup and

d i s t i l l a t i o n y i e l d e d 0.465 g ( 6 4 % ) o f a v i s c o u s y e l l o w o i l

which GLC a n a l y s i s r e v e a l e d t o b e m a i n l y ( 8 5 % )

p h o t o a d d u c t s - 1 0 + - 11. GLC and 1~ nmr a n a l y s i s showed

1 0 : l l t o be p r e s e n t i n t h e r a t i o o f 57:43. The r a t i o of 7 -

1 0 : l l was f o u n d by GLC t o b e c o n s t a n t t h r o u g h o u t t h e -- i r r a d i a t i o n .

3. S o l v e n t S t u d i e s - I r r a d i a t i o n o f 6 and A c r y l o n i t r i l e

i n E t h e r

A s o l u t i o n o f 0.218 g ( 1 . 9 4 rnmol, 1 .0 e q ) 6, 0.823 g

(15.5 m m o l , 8 .0 e q ) a c r y l o n i t r i l e and 0.082 g undecane i n

1 0 0 mL anhyd. e t h e r was p l a c e d i n a q u a r t z t o r u s reactor

and i r r a d i a t e d t h r o u g h a Vycor f i l t e r a t ambien t

t e m p e r a t u r e . GLC a n a l y s i s of a l i q u o t s r e v e a l e d f o r m a t i o n

of a complex m i x t u r e , of which compounds - 1 0 and 11

a c c o u n t e d f o r o n l y 5% by GLC. T h e i r p r e s e n c e was

c o n f i r m e d by a mixed s a m p l e GLC e x p e r i m e n t . The d e c r e a s e

i n t h e amount of t h e s t a r t i n g l a c t o n e 5 r e l a t i v e t o

i n t e r n a l s t a n d a r d s t o p p e d a f t e r 2 h r o f i r r a d i a t i o n and

less t h a n 30% of - 6 was consumed. T h i s may have been d u e

t o t h e f o r m a t i o n of a p o l y m e r i c c o a t i n g o n t h e walls o f

t h e reactor.

4 . S o l v e n t S t u d i e s - I r r a d i a t i o n o f 6 and A c r y l o n i t r i l e

i n Ace tone

A s o l u t i o n of 0.239 g ( 2 . 1 3 m m o l , 1 . 0 eq) 5, 0.902 g

( 1 7 . 0 mmol, 8.0 e q ) a c r y l o n i t r i l e and 0.075 g undecane i n

1 0 0 mL s p e c . g r a d e acetone was p l a c e d i n a qua . r tz torus

reactor ( F i g . 5 ) and i r r a d i a t e d t h r o u g h a Vycor f i l t e r a t

a m b i e n t t e m p e r a t u r e . GLC a n a l y s i s o f a l i q u o t s r e v e a l e d

t h e f o r m a t i o n of a complex m i x t u r e i n which compounds 10 a n d - 11 a c c o u n t e d f o r less t h a n 3% by GLC. The consumpt ion

o f t h e l a c t o n e - 6 s t o p p e d a f t e r 1 . 5 h r o f i r r a d i a t i o n

l e a v i n g - ca. 60% of - 6 u n r e a c t e d a n d a d e n s e p o l y m e r i c

c o a t i n g on t h e r e a c t o r walls.

5. S o l v e n t S t u d i e s - I r r a d i a t i o n o f 6 and

A c r y l o n i t r i l e i n I s o p r o p a n o l

A s o l u t i o n o f 0.320 g ( 2 . 8 5 mmol, 1 . 0 e q ) - 6, 1 .21 g

( 2 2 . 8 mmol, 8.0 eq) a c r y l o n i t r i l e and 0.062 g undecane i n

1 0 0 mL HPLC g r a d e i s o p r o p a n o l was p l a c e d i n a q u a r t z

t o r u s r e a c t o r and i r r a d i a t e d t h r o u g h a Vycor f i l t e r a t

ambien t t e m p e r a t u r e . GLC a n a l y s i s o f a l i q u o t s r e v e a l e d

t h e f o r m a t i o n of a complex m i x t u r e i n which compounds 1 0 - and 11 were n o t d e t e c t e d . The consumpt ion of t h e l a c t o n e - 6 s t o p p e d a f t e r 3 h r of i r r a d i a t i o n l e a v i n g c a . 40% - 7

u n r e a c t e d and a d e n s e p o l y m e r i c c o a t i n g on t h e lamp

jacket. Mixed sample GLC e x p e r i m e n t showed p h o t o a d d u c t s

1 0 + 11 were p r e s e n t as minor components (<.I%) i n t h e - - c r u d e m i x t u r e a f t e r workup.

6. F i l t e r E x p e r i m e n t s - Use of a Corex F i l t e r i n

I r r a d i a t i o n o f 6 and A c r y l o n i t r i l e

A s o l u t i o n o f 0.254 g (2 .26 mmol, 1 . 0 eq) - 6, 0.960 g

( 1 8 . 1 mmol, 8 eq) a c r y l o n i t r i l e and 0.092 g undecane i n

1 5 0 mL a c e t o n i t r i l e was p l a c e d i n a Pyrex immersion well

and i r r a d i a t e d t h r o u g h a Corex f i l t e r (50% t r a n s m i s s i o n @

. 290 nm). GLC a n a l y s i s o f a l i q u o t s r e v e a l e d no consumpt ion

o f s t a r t i n g material. After 2 h r o f i r r a d i a t i o n t h e

s o l u t i o n was t r e a t e d w i t h c h a r c o a l , f i l t e r e d and

c o n c e n t r a t e d i n vacua . The l a c t o n e 6 was r e c o v e r e d - q u a n t i t a t i v e l y .

7. F i l t e r E x p e r i m e n t s - Use o f a P y r e x F i l t e r i n

I r r a d i a t i o n o f 6 w i t h , A e r y l o n i t r i l e

Us ing a p r o c e d u r e i d e n t i c a l t o t h e p r e v i o u s case a

s o l u t i o n o f 5, a c r y l o n i t r i l e and i n t e r n a l s t a n d a r d was

i r r a d i a t e d t h r o u g h a Pyrex f i l t e r (50% t r a n s m i s s i o n

@ 305 nm) f o r 2 h r . GLC a n a l y s i s r e v e a l e d no r e a c t i o n .

I d e n t i c a l workup q u a n t i t a t i v e l y y i e l d e d t h e s t a r t i n g

l a c t o n e .

8. A t t empted P h o t o i s o m e r i z a t i o n o f 1 0

A s o l u t i o n o f 0.033 g - 1 0 i n 1 0 mL a c e t o n i t r i l e was

p l a c e d i n a q u a r t z t e s t t u b e e q u i p p e d w i t h a n i t r o g e n

b u b b l e r and t a p e d t o t h e s i d e o f t h e lamp jacket. T h i s

s o l u t i o n was i r r a d i a t e d f o r 1 h r t h r o u g h a Vycor f i l t e r .

GLC a n a l y s i s r e v e a l e d o n l y - 1 0 p r e s e n t . Removal o f t h e

s o l v e n t i n v a c u o r e s u l t e d i n q u a n t i t a t i v e r e c o v e r y o f 2.

9. At t empted P h o t o i s o m e r i z a t i o n o f 11

A s o l u t i o n of 0.027 g o f ll, which was 95:5 1 0 : l l

by GLC, i n 1 0 mL of a c e t o n i t r i l e was p l a c e d i n a q u a r t z

t es t t u b e e q u i p p e d w i t h a n i t r o g e n b u b b l e r and t a p e d t o

t h e s i d e o f t h e lamp j a c k e t . T h i s s o l u t i o n was i r r a d i a t e d

f o r 1 h r t h r o u g h a Vycor f i l t e r . GLC a n a l y s i s r e v e a l e d

t h e r a t i o of -- 1 0 : l l t o be unchanged. Removal of t h e

s o l v e n t i n vacuo r e s u l t e d i n q u a n t i t a t i v e r e c o v e r y of

1 0 and 11 i n t h e i n i t i a l r a t i o . - -

1 0 . Base I s o m e r i z a t i o n o f 1 0 and 11

To a s o l u t i o n o f 0.015 g - 1 0 and 0.011 g undecane i n

1 0 mL anhyd. e t h a n o l was added 2 mL 1 . 2 M N a O E t . The

r e s u l t i n g s o l u t i o n was s t i r r e d a t room t e m p e r a t u r e under

N2 w h i l e 0.1 mL a l i q u o t s were removed a t i n t e r v a l s and

e a c h quenched by a d d i t i o n t o 2 mL o f 5% HC1. T h i s m i x t u r e

was e x t r a c t e d w i t h Et2O and t h e o r g a n i c extract was washed

w i t h s a t . NaHC03, d r i e d o v e r anhyd. Na2S04 and f i l t e r e d .

The r e s u l t i n g s o l u t i o n was a n a l y s e d by GLC which r e v e a l e d

t h a t a m i x t u r e o f -- 1 0 : l l i n t h e r a t i o o f 80:20 had been

formed w i t h i n 1 5 min. The r a t i o d i d n o t change o v e r 2

h r . The r e a c t i o n components were i d e n t i f i e d as - 1 0 and 2

by mixed s a m p l e GLC e x p e r i m e n t s .

A sample o f - 11 t r e a t e d i n a n i d e n t i c a l manner was

found t o i s o m e r i z e t o a m i x t u r e o f 1 0 : l l i n t h e r a t i o of -- 80:20 w i t h i n 30 min. Mixed sample GLC e x p e r i m e n t s

c o n f i r m e d t h e i d e n t i t y o f t h e 2 components p r e s e n t as 10 and 11. -

T h i s e x p e r i m e n t was r e p e a t e d o n a sample o f - 1 0 u s i n g

e t h a n o l D6 as a s o l v e n t a n d a n a l y s i s o f t h e e q u i l i b r i a t e d

11. Attempted Alumina C a t a l y s e d I s o m e r i z a t i o n of 1 0

A 0.025 g sample o f - 1 0 was p l a c e d o n column of

2.0 g n e u t r a l Alumina ( a c t i v i t y I ) and e l u t e d w i t h

CHC13 ( 1 5 mL). Removal o f t h e s o l v e n t gave 0.020 g of

material which mixed sample GLC e x p e r i m e n t s showed t o be

e x c l u s i v e l y compound - 1 0 . A 0.050 g sample of compound - 11

was t r e a t e d i n a s imi l a r manner and was r e c o v e r e d ( 8 0 % )

unchanged. The 1~ nmr s p e c t r a of t h e s e s a m p l e s were

i d e n t i c a l t o t h e m a t e r i a l s b e f o r e a lumina t r e a t m e n t .

B. P h o t o a d d i t i o n of a - c h l o r o a c r y l o n i t r i l e to

1. Ambient Tempera ture P h o t o l y s i s

A s o l u t i o n of 0.322 g (2 .87 m m o l , 1 .0 e q ) 6 , 2.01 g

( 2 3 . 0 mmol, 8.0 e q ) a - c h l o r o a c r y l o n i t r i l e and 0.087 g

undecane i n 200 mL a c e t o n i t r i l e was p l a c e d i n a Pyrex

immersion w e l l and i r r a d i a t e d t h r o u g h a Vycor f i l t e r a t

ambien t t e m p e r a t u r e . The t e m p e r a t u r e of t h e s o l u t i o n

s t a b i l i z e d a t 40•‹C a f t e r 0.5 h r o f i r r a d i a t i o n . GLC

a n a l y s i s of a l i q u o t s r e v e a l e d t h a t t h e s t a r t i n g

l a c t o n e - 6 had been consumed a f t e r 4 h r . The u s u a l workup

g a v e a v i s c o u s brown o i l which c r y s t a l l i z e d o n s t a n d i n g

and was r e c r y s t a l l i z e d twice from e t h a n o l t o y i e l d

0.310 g ( 5 4 % ) of l i g h t y e l l o w n e e d l e s , m.p. 94-96%. GLC

a n a l y s i s of t h i s m a t e r i a l r e v e a l e d o n l y two compounds,

1 2 + 1 3 , i n t h e r a t i o o f 58:42 i n o r d e r o f i n c r e a s i n g - - r e t e n t i o n t i m e . The r a t i o o f t h e two compounds was found

t o be c o n s t a n t t h r o u g h o u t t h e c o u r s e o f t h e i r r a d i a t i o n .

The two p h o t o a d d u c t s were u n r e s o l v e d by TLC and f l a s h

ch romatography . The IH a n d 13c s p e c t r a were a s s i g n e d o n

t h e b a s i s o f r e l a t i v e i n t e n s i t i e s o f t h e s i g n a l s , which

were i n a g r e e m e n t w i t h t h e r e l a t ive p r o p o r t i o n s found by

GLC. The 1 3 ~ nmr a s s i g n m e n t s m u s t be viewed w i t h c a u t i o n

s i n c e t h e isomer r a t i o (12 :13 ) -- is n e a r l y u n i t y . Due t o

N u c l e a r O v e r h a u s e r e f f e c t s t h e i n t e n s i t i e s o f 1 3 ~ s i g n a l s

are n o t a d i r e c t measu re o f t h e r e l a t i v e abundance o f a

p a r t i c u l a r c a r b o n i n a m i x t u r e . I r ( K B r p e l l e t ) : 2240(w) ,

Major isomer - 12 : 1~ nrnr(CDC13) 6 : 1 .48(3H, CH3, s ) ,

1.8-2.2(2Hf Cg, m ) , 2.70(1Hf C7, dd , 5 ~ 1 3 . 8 H Z f 0 .8 HZ)

3.07(1Hf c 7 , d d , J=13 .8 Hz, 1 . 2 Hz), 3 . 4 6 ( 1 ~ , C 1 , b r s ) ,

1 1 2 ( 2 8 ) , 9 3 ( 2 8 ) , 8 2 ( 1 0 0 ) *

Minor isomer - 13 : IH n m r ( C ~ C 1 3 ) 6 : 1 .44(3Hf CH3, s ) ,

1.9-2.1(2Hf C5, m ) , 2.78(1Hf C7, dd , 5-14.4 Hz, 1 .4 H z ) ,

3.02(1HI C7, d d , 5 ~ 1 4 . 4 H Z f 1 .2 H Z ) , 3.68(1Hf C 1 , dd ,

1 1 2 ( 2 4 ) , 1 0 4 ( 4 1 ) , 8 2 ( 7 8 ) , 6 5 ( 2 2 ) .

MS o f m i x t u r e ( C 1 , i s o b u t a n e , d i r e c t p r o b e ) : 2 0 2 ( 3 2 ,

M+3), 2 0 0 ( 1 0 0 , M+1), 1 6 6 ( 8 ) , 1 6 4 ( 6 ) .

Ana l . (of m i x t u r e ) C a l c d . f o r CgHloNO2Cl: C, 54 .15 ;

H , 5 .05; N , 7 .02. Found: C , 54 .12 ; H , 4.98; N , 6.84.

2. Low T e m p e r a t u r e P h o t o l y s i s

A s o l u t i o n o f 0.249 g ( 2 . 3 1 m m o l , 1 . 0 eq) - 6 , 1 .62 g

( 1 8 . 5 mmol, 8 .0 eq) a - c h l o r o a c r y l o n i t r i l e and 0 .067 g

u n d e c a n e i n 200 mL a c e t o n i t r i l e was p l a c e d i n a P y r e x

i m m e r s i o n w e l l a n d c o o l e d t o -40•‹c i n a n ace tone /C02

b a t h . T h i s s o l u t i o n was i r r a d i a t e d t h r o u g h a Vycor f i l t e r

a n d t h e t e m p e r a t u r e o f t h e s o l u t i o n s t a b i l i z e d a t -20•‹C

a f t e r 30 min. GLC a n a l y s i s o f a l i q u o t s r e v e a l e d t h a t t h e

l a c t o n e - 6 h a d b e e n consumed a f t e r 3.5 h r . The u s u a l

workup g a v e a v i s c o u s y e l l o w o i l wh ich c r y s t a l l i z e d o n

s t a n d i n g . R e c r y s t a l l i z a t i o n f r o m t o l u e n e y i e l d e d 0.284

g ( 6 2 % ) o f l i g h t y e l l o w n e e d l e s , mop. 94 .5 -96O~ . GLC a n d

1~ nmr a n a l y s i s showed t h i s material t o b e a m i x t u r e of

t h e d i a s t e r e o m e r i c p h o t o a d d u c t s 12 and - 1 3 i n t h e r a t i o o f

57:43. The r a t i o o f t h e two a d d u c t s was f o u n d t o b e

c o n s t a n t i n a l l t h e a l i q u o t s t a k e n d u r i n g t h e i r r a d i a t i o n .

3. F i l t e r S t u d i e s - Use of a P y r e x F i l t e r i n I r r a d i a t i o n

of 6 and a - c h l o r o a c r y l o n i t r i l e

A s o l u t i o n o f 0.575 g ( 5 . 1 3 mmol, 1 .0 e q ) 6 , 3.32 g

(38 .0 mmol, 7.4 e q ) a - c h l o r o a c r y l o n i t r i l e and 0.102 g

undecane i n 200 mL a c e t o n i t r i l e was p l a c e d i n a Pyrex

immersion well and i r r a d i a t e d t h r o u g h a Pyrex f i l t e r a t

ambien t t e m p e r a t u r e f o r 2 h r . GLC a n a l y s i s of a l i q u o t s

r e v e a l e d many minor p r o d u c t s formed b u t t h a t - ca. 95% o f

t h e l a c t o n e remained u n r e a c t e d . The Pyrex f i l t e r was

r e p l a c e d w i t h a Corex f i l t e r and t h e s o l u t i o n i r r a d i a t e d

f o r an a d d i t i o n a l 2 h r . GLC a n a l y s i s r e v e a l e d t h a t - ca.

90% of t h e l a c t o n e - 6 remained u n r e a c t e d . T rea tmen t o f t h e

y e l l o w s o l u t i o n w i t h c h a r c o a l , c o n c e n t r a t i o n i n vacuo and

b u l b t o b u l b d i s t i l l a t i o n gave 0.471 g ( 8 2 % ) of l a c t o n e 5 which was 93% p u r e by GLC.

4 . S o l v e n t S t u d i e s - I r r a d i a t i o n o f 6 and

a - c h l o r o a c r y l o n i t r i l e i n Ace tone

A s o l u t i o n o f 0.578 g ( 5 . 1 6 mmol, 1 .0 e q ) 5, 4.51 g

(51.6 mmol, 1 0 e q ) a - c h l o r o a c r y l o n i t t i l e and 0.113 g

undecane i n 200 mL s p e c . g r a d e a c e t o n e was p l a c e d i n a

Pyrex immers ion well and i r r a d i a t e d t h r o u g h a Pyrex f i l t e r

a t ambient t e m p e r a t u r e f o r 2 h r . GLC a n a l y s i s o f a l i q u o t s

r e v e a l e d t h e f o r m a t i o n o f a complex m i x t u r e of p r o d u c t s

and E. 90% o f - 6 u n r e a c t e d . The Pyrex f i l t e r was r e p l a c e d

w i t h a Vycor f i l t e r and t h e s o l u t i o n i r r a d i a t e d f o r a n

a d d i t i o n a l 3 h r . GLC a n a l y s i s showed a complex m i x t u r e o f

p r o d u c t s w i t h - ca. 80% of - 6 u n r e a c t e d . GLC a n a l y s i s of t h e

i n i t i a l ( t i m e = O ) s ample k e p t i n t h e d a r k r e v e a l e d o n l y

u n r e a c t e d s t a r t i n g m a t e r i a l s .

5. S o l v e n t S t u d i e s - E t h e r

A s o l u t i o n o f 0.446 g ( 3 . 9 8 m m o l , 1 .0 e q ) 5, 2.60 g

(29 .8 mmol, 7 .5 e q ) a - c h l o r o a c r y l o n i t r i l e and 0.092 g

undecane i n 200 mL anhyd. e t h e r was p l a c e d i n a Pyrex

immers ion well and i r r a d i a t e d t h r o u g h a Vycor f i l t e r a t

ambien t t e m p e r a t u r e f o r 3 h r . GLC a n a l y s i s r e v e a l e d t h e

f o r m a t i o n o f a complex m i x t u r e of a p r o d u c t s and - ca. 60%

of u n r e a c t e d - 6. GLC a n a l y s i s o f t h e i n i t i a l ( t i m e = O )

s a m p l e k e p t i n t h e d a r k r e v e a l e d o n l y u n r e a c t e d s t a r t i n g

material.

6. S o l v e n t S t u d i e s - I r r a d i a t i o n o f 6 and

a - c h l o r o a c r y l o n i t r i l e i n Methanol

A s o l u t i o n o f 0.307 g (2 .74 mmol, 1 . 0 e q ) - 6, 1 .80 g

( 2 0 . 5 mmol, 7 .5 e q ) a - c h l o r o a c r y l o n i t r i l e and 0.083 g

undecane i n 200 mL HPLC g r a d e me thano l was p l a c e d i n a

Pyrex immersion well and i r r a d i a t e d t h r o u g h a Vycor f i l t e r

a t ambien t t e m p e r a t u r e f o r 4 h r . GLC a n a l y s i s r e v e a l e d

t h e f o r m a t i o n of a complex m i x t u r e of p r o d u c t s and z. 70%

of unreacted - 6. GLC ana ly s i s of the i n i t i a l (time=O)

sample kept i n t he dark showed only unreacted s t a r t i n g

mate r ia l s .

C. Photoaddit ion of a -ace toxyacry lon i t r i l e t o

1. Ambient Temperature Photolys is

A s o l u t i o n of 0.902 g(8.05 mmol, 1.0 eq ) - 6, 5.0 g

(45 mmol, 5.6 eq ) a - ace toxyac ry lon i t r i l e and 0.085 g

t r idecane i n 200 mL a c e t o n i t r i l e was placed i n a Pyrex

immersion w e l l and i r r a d i a t e d through a Vycor f i l t e r f o r

24 hr a t ambient temperature. The temperature of the

so lu t i on s t a b i l i z e d a t 40% a f t e r 1 hour of i r r ad i a t i on .

The usual workup and shor tpa th d i s t i l l a t i o n (bulb temp

125-1400~/.3 t o r r ) yielded 1.05 g(56%) of a viscous yellow

o i l which GLC ana ly s i s revealed t o be a m i x t u r e of three

compounds, - - - 1 4 , 15, 16 i n t h e r a t i o of 3.4:3.8:1. This

mixture gave only one spo t on TLC and was unresolved by

f l a s h chromatography a s well as reverse phase HPLC.

Reduction of t he temperature of t h e i n j e c t i o n po r t from

275% t o 225% before a GLC ana ly s i s r e su l t ed i n the

e l iminat ion of t he f a s t e s t e l u t i n g compound - 1 4 from the

GLC t r a c e and t h e r a t i o of the two remaining adducts - 15

and - 1 6 was found t o be 3: 2 i n order of increas ing

r e t en t i on time. T h i s was cons i s ten t with 1~ and 1 3 ~ nmr

a n a l y s i s o f t h e m i x t u r e . P r e p a r a t i v e GLC o f t h e m i x t u r e

r e s u l t e d i n t h e i s o l a t i o n o f t h e f a s t e s t e l u t i n g compound,

1 4 , which was i d e n t i f i e d b y 1 H nmr spec t ra l a n a l y s i s 7

( b e l o w ) as t h e r i n g opened e l i m i n a t i o n p r o d u c t ,

4-Cyano-6-methyloxacycloocta-3,5-diene-2-one.

B e c a u s e o f t h e p r e d o m i n a n c e o f t h e f a s t e r e l u t i n g

a d d u c t - 1 5 it was p o s s i b l e t o a s s i g n t h e IH and 1% nmr

spectra o f t h e m i x t u r e by u s i n g ( w i t h c a u t i o n i n t h e case

o f 1%) t h e r e l a t i v e i n t e n s i t i e s . The s t e r e o c h e m i s t r y a t

C7 was a s s i g n e d b y c o m p a r i s o n o f c h e m i c a l s h i f t o f t h e

m e t h y l r e s o n a n c e s as d e s c r i b e d i n t h e R e s u l t s and

D i s c u s s i o n .

4-Cyano-6-methyloxacycloocta-3,5-diene-2-one 1 4 - 1 ; 1 H

n m r ( C ~ C 1 3 ) d : 2.12(3H, CH3, s ) , 2.57(2H, C3, t r , J = 7 H Z ) ,

4 .40(2H, C2, t r , J = 7 Hz) , 6 .02(1H, Cg, s ) , 6.37(1H, C7,

s ) t ms(c1, I s o b u t a n e ) : 1 6 5 ( 1 1 , M+2), 1 6 4 ( 1 0 0 , M t l ) .

CH3, s), 1 . 7 - 1 .8 (2H, Cg, m ) , 2 . 15 (38 , CH3, $ 1 , 2 .53(18 ,

3.55(1H, C 1 , t r , J = 1 . 6 H z ) , 4.3-4.4(2H, Cq, m ) ; 1%

66.30(C8, s,), 66.11(C4, tr), 51.85(C1, dl, 43.61(C7, tr),

33.12(C5, tr), 32.64(C6, s), 27.58(CH3, q), 20.33(CH3, q);

ms(C1, Isobutane): 225(13, M+2), 224(100, M+l), 182(8).

endo-8-Acetoxy-8-cyano-6-methyl-3-oxabicyclo - [4.2.O]octan-2-one(l6); - 1~ nmr (CDCl3) 6 : 1.36(3H,

CH3, s), 1.8-1.9(2H, Cg, m), 2.13(3H, CH3, s), 2.34(1H,

C7, dd, J= 14 Hz, 0.8 Hz), 2.97(1H, C7, dd, 53 14 HZ, 1

tr), 31.91(C6, s), 27.18(CH3, q), 20.31(CH3, q); ms(C1,

Isobutane): 225(14,Mt2), 224(100, Mtl), l66(8), l64(16).

Anal. (of mixture) Calcd. for CllH13N04: C, 59.19; H,

5.87; N, 6.28. Found: C, 59.09; H, 5.85; N, 6.06.

2. Low temperature Photolysis

A solution of 0.224 g(2.00 mmol, 1.0 eq) - 6, 1.33 g

(12 mmol, 6.0 eq) a-acetoxyacrylonitrile and 0.056 g

undecane in 200 mL acetonitrile was placed in a Pyrex

immersion well and cooled to -40•‹c with an acetone/C02

bath and irradiated through a Vycor filter for 8 hr. The

temperature of the solution stabilized at -2S0c after 0.5

hr. GLC analysis of aliquots was performed with the

injection port temperature at 2250~. The usual workup and

shortpath distillation yielded 0.285 g(64%) of a viscous

y e l l o w o i l which b o t h GLC and 1~ nmr a n a l y s i s r e v e a l e d t o

be a m i x t u r e of - 1 5 and - 1 6 i n t h e r a t i o of - c a . 3:2. W i t h i n

e x p e r i m e n t a l e r ro r t h i s r a t i o was found t o be f a i r l y

c o n s t a n t d u r i n g t h e i r r a d i a t i o n .

P h o t o a d d i t i o n of a c r y l o n i t r i l e t o 2 - p e n t e n o l i d e ( 7 )

1. Ambient Tempera tu re P h o t o l y s i s

A s o l u t i o n o f 0.369 g (3 .76 mmol, 1 . 0 e q )

2 - p e n t e n o l i d e ( Z ) , 1 .670 g ( 3 1 . 5 mmol, 8.4 e q ) a c r y l o n i t r i l e

and 0.108 g undecane i n 150 mL a c e t o n i t r i l e was p l a c e d i n

a Vycor t o r u s r e a c t o r and i r r a d i a t e d a t ambient

t e m p e r a t u r e f o r 5 .5 h r . GLC a n a l y s i s o f a l i q u o t s r e v e a l e d

t h e g r a d u a l f o r m a t i o n of two p r o d u c t s , 17 and - 1 8 i n t h e

r a t i o of 53:47 i n o r d e r of i n c r e a s i n g r e t e n t i o n time. The

r a t i o between t h e two p r o d u c t s was found t o be c o n s t a n t

t h r o u g h o u t t h e i r r a d i a t i o n . GLC a n a l y s i s of t h e i n i t i a l

( t i m e = O ) sample k e p t i n t h e d a r k r e v e a l e d o n l y u n r e a c t e d

s t a r t i n g materials. The u s u a l workup and s h o r t p a t h

d i s t i l l a t i o n y i e l d e d 0.568 g ( 6 5 % ) of a v i s c o u s y e l l o w o i l

which was p r e d o m i n a n t l y compounds - 1 7 and - 1 8 i n t h e r a t i o

of 55:45 by GLC. T h i s m i x t u r e e x h i b i t e d one s p o t on TLC

and was u n r e s o l v e d by f l a s h chromatography and HPLC. The

s i g n a l s i n t h e 1~ nmr spec t rum of t h e m i x t u r e were

u n a s s i g n a b l e d u e t o o v e r l a p of s i g n a l s b u t t h e s i g n a l s i n

t h e 1% nmr s p e c t r a were a s s i g n e d by compar ison of t h e

s p e c t r a a f t e r b a s e e q u i l i b r i a t i o n ; i r ( f i l m ) : 2250(w) ,

28.20(C7, t r ) , 24.62(C6, d ) ; ms(C1, i s o b u t a n e ) :

27.51(C7, t r ) , 23.54(C6, d ) ; m s ( C 1 , i s o b u t a n e ) : 1 5 3 ( 8 ,

M+2), 1 5 2 ( 1 0 0 , M+1).

Anal . o f m i x t u r e , C a l c d . f o r CgHgN02: C , 63.56; H I

6.00; N , 9.27. Found: C, 63.32; H, 5.83; N , 9.08.

2. Low T e m p e r a t u r e P h o t o l y s i s

A s o l u t i o n o f 0.350 g ( 3 . 5 7 m m o l , 1 . 0 e q )

2 - p e n t e n o l i d e , 1 .518 g ( 2 8 . 6 m m o l , 8.0 e q ) a c r y l o n i t r i l e

and 0.111 g undecane i n 200 mL a c r y l o n i t r i l e was p l a c e d i n

a Pyrex immersion well a n d c o o l e d t o - 4 0 0 ~ w i t h an

ace tone/C02 b a t h and i r r a d i a t e d t h r o u g h a Vycor f i l t e r f o r

2 h r . The u s u a l workup and s h o r t p a t h d i s t i l l a t i o n y i e l d e d

a v i s c o u s y e l l o w o i l which c r y s t a l l i z e d on s t a n d i n g .

R e c r y s t a l l i z a t i o n from i s o p r o p a n o l y i e l d e d 0.327 g ( 6 0 % ) o f

l i g h t y e l l o w n e e d l e s , m.p. 1 2 4 - 1 2 7 0 ~ . GLC a n a l y s i s o f

t h i s m a t e r i a l r e v e a l e d it t o be 17:I.J i n t h e r a t i o o f

60:40. T h i s r a t i o was found t o b e c o n s t a n t t h r o u g h o u t t h e

i r r a d i a t i o n .

3. Base I s o m e r i z a t i o n of 1 7 and 1 8

To a s o l u t i o n of 0.102 g o f t h e c r y s t a l l i n e m i x t u r e

of -- 17:18 (60 :40) i n 30 mL anhyd. e t h a n o l was added 1 0 mL

1 .2 M N a O E t and t h e r e s u l t i n g s o l u t i o n s t i r r e d a t ambient

t e m p e r a t u r e . 0 .1 mL a l i q u o t s were t a k e n a t i n t e r v a l s ,

worked u p and a n a l y s e d as b e f o r e t o r e v e a l t h a t a m i x t u r e

o f -- 17:18 i n t h e r a t i o o f 75:25 had been formed w i t h i n 30

min. T h i s r a t i o d i d n o t change o v e r 2 h r . A f t e r 2 h r a t

ambient t e m p e r a t u r e , t h e r e m a i n i n g b a s i c s o l u t i o n was

c a r e f u l l y n e u t r a l i z e d w i t h 2 N HC1 and t h e s o l v e n t removed

under vacuum. The r e s i d u e was d i s s o l v e d i n 30 mL E t a 0 and

washed w i t h 2x10 mL H20 and 1 5 mL s a t . NaHC03. The

o r g a n i c e x t r a c t was d r i e d o v e r anhyd. MgS04, f i l t e r e d and

c o n c e n t r a t e d i n vacuo . The r e s i d u e was p u r i f i e d by

s h o r t p a t h d i s t i l l a t i o n t o y i e l d 0.085 g ( 8 3 % ) of a v i s c o u s

y e l l o w o i l which mixed s a m p l e GLC a n a l y s i s r e v e a l e d t o be

a m i x t u r e o f -- 17:18 i n t h e r a t i o o f 73:27.

4 . At tempted P h o t o i s o m e r i z a t i o n o f 1 7 and 1 8

A s o l u t i o n o f 0.055 g o f t h e m i x t u r e of -- 15:18 i n t h e

r a t i o of 73:27, a n d 0.15 g undecane i n 1 0 mL a c e t o n i t r i l e

was p l a c e d i n a q u a r t z t e s t t u b e and t a p e d t o t h e s i d e o f

t h e lamp j a c k e t . T h i s s o l u t i o n was i r r a d i a t e d t h r o u g h a

Vycor f i l t e r f o r o n e h o u r . GLC a n a l y s i s of t h e s o l u t i o n

r e v e a l e d no c h a n g e i n t h e r e l a t i v e amounts of - 1 7 and - 1 8

d u r i n g t h e c o u r s e o f t h e i r r a d i a t i o n . The sample was

r e c o v e r e d by t r e a t i n g t h e s o l u t i o n w i t h c a . 1 g a c t i v a t e d - c h a r c o a l , f i l t e r i n g and c o n c e n t r a t i o n i n vacuo t o y i e l d

0.058 g of a v i s c o u s y e l l o w o i l .

E. P h o t o a d d i t i o n of a - c h l o r o a c r y l o n i t r i l e t o

1. Ambient Tempera tu re P h o t o l y s i s

A s o l u t i o n o f 0.220 g (2 .24 m m o l , 1 .0 e q )

2 - p e n t e n o l i d e , 0.976 g (11 .2 m m o l , 5 .0 e q )

a - c h l o r o a c r y l o n i t r i l e and 0.107 g undecane i n 150 mL

a c e t o n i t r i l e was p l a c e d i n a Vycor t o r u s reactor and

i r r a d i a t e d a t a m b i e n t t e m p e r a t u r e . GLC a n a l y s i s of

a l i q u o t s showed t h a t t h e consumpt ion o f t h e l a c t o n e 2 c e a s e d a f t e r 2 h r o f i r r a d i a t i o n l e a v i n g ca. 70% - u n r e a c t e d . A s w e l l a complex m i x t u r e dominated by two

p r o d u c t s was p roduced . Extended i r r a d i a t i o n i n c r e a s e d

t h e c o m p l e x i t y o f t h e m i x t u r e . The r a t i o o f t h e two

p r i n c i p a l p r o d u c t s -- 19:20 was found t o be 40:60 and

c o n s t a n t t h r o u g h o u t t h e i r r a d i a t i o n . GLC a n a l y s i s of t h e

i n i t i a l ( t i m e = O ) s ample k e p t i n t h e d a r k r e v e a l e d o n l y

u n r e a c t e d s t a r t i n g materials.

2. Low Tempera tu re P h o t o l y s i s

A s o l u t i o n o f 0.205 g (2 .09 mmol, 1 .0 e q )

2 - p e n t e n o l i d e , 0.727 g ( 8 . 3 0 mmol, 4 .0 e q )

a - c h l o r o a c r y l o n i t r i l e a n d 0.066 g undecane i n 150 mL

a c e t o n i t r i l e was p l a c e d i n a P y r e x immersion well, c o o l e d

t o -30% a n d i r r a d i a t e d t h r o u g h a Vycor f i l t e r . The

t e m p e r a t u r e of t h e s o l u t i o n s t a b i l i z e d a t -20% a f t e r

0.5 h r o f i r r a d i a t i o n . GLC a n a l y s i s of a l i q u o t s r e v e a l e d

t h e consumpt ion of t h e l a c t o n e c e a s e d a f t e r 4.5 h r of

i r r a d i a t i o n l e a v i n g E. 30% u n r e a c t e d . A s well a complex

m i x t u r e of p r o d u c t s d o m i n a t e d by 2 and - 20 was produced .

The r a t i o of t h e s e two p r o d u c t s was c o n s t a n t t h r o u g h o u t

t h e i r r a d i a t i o n a n d found t o be 35:65. The u s u a l workup

and s h o r t p a t h d i s t i l l a t i o n y i e l d e d 0.127 g of a y e l l o w o i l

which was a complex m i x t u r e o f t h e s t a r t i n g l a c t o n e and

p h o t o p r o d u c t s by GLC. The p r o d u c t s - 1 9 and 20 were - s e p a r a t e d from t h e s t a r t i n g l a c t o n e by f l a s h

ch romatography o n s i l i c a g e l t o y i e l d , a f t e r s h o r t p a t h

d i s t i l l a t i o n , a v i s c o u s y e l l o w o i l which weighed 0.0931

g ( 2 9 % ) . GLC a n a l y s i s r e v e a l e d t h e o i l t o be a m i x t u r e of

1 9 and 20 i n t h e r a t i o o f 40:60. Repea ted f l a s h - - chromatography o n S i l i c a G e l u s i n g a c e t o n i t r i l e : t o l u e n e

1:9 as t h e e l u a n t p a r t i a l l y r e s o l v e d t h e m i x t u r e i n t o two

f r a c t i o n s , o n e c o n t a i n i n g a 20:80 m i x t u r e o f -- 19:20 and t h e

o t h e r a 70:30 m i x t u r e o f -- 19:20. T h i s d e g r e e o f e n r i c h m e n t

i n e a c h component a l l o w e d t h e s i g n a l s i n t h e 1 3 ~ nmr

s p e c t r a o f e a c h component t o be a s s i g n e d ; i r ( f i 1 m ) of

c r u d e m i x t u r e : 2250(w) , 1 7 3 0 ( s ) , 1 4 9 0 ( w ) , 1 4 4 0 ( w ) ,

3. At t empted P h o t o i s o m e r i z a t i o n of 1 9 and 20

A s o l u t i o n o f 0.024 g o f t h e c h r o m a t o g r a p h i c f r a c t i o n

c o n t a i n i n g -- 19:20 i n t h e r a t i o o f 70:30 and 0.015 g

undecane i n 1 0 mL a c e t o n i t r i l e was p l a c e d i n a q u a r t z t e s t

t u b e e q u i p p e d w i t h a N2 b u b b l e r and t a p e d t o t h e s i d e o f

t h e lamp j a c k e t . T h i s s o l u t i o n was i r r a d i a t e d th rough a

Vycor f i l t e r f o r 2 h r a t a m b i e n t t e m p e r a t u r e . GLC

a n a l y s i s showed a h o s t of minor p r o d u c t s n o t p r e s e n t i n

t h e o r i g i n a l sample and t h a t t h e r a t i o o f 19 t o 20 had

changed t o 67:33. Comparison of t h e areas t o t h e i n t e r n a l

s t a n d a r d r e v e a l e d t h a t E. 5% o f e a c h i somer had

decomposed d u r i n g t h e i r r a d i a t i o n .

F. P h o t o a d d i t i o n of a - a c e t o x y a c r y l o n i t r i l e t o

2 - p e n t e n o l i d e ( 7 )

1. Ambient T e m p e r a t u r e P h o t o l y s i s

A s o l u t i o n o f 0.210 g ( 2 . 1 4 m m o l , 1 .0 e q )

2 - p e n t e n o l i d e , 1 .189 g ( 1 0 . 7 mmol, 5.0 e q )

a - a c e t o x y a c r y l o n i t r i l e and 0.075 g undecane i n 150 mL

a c e t o n i t r i l e was p l a c e d i n a Vycor t o r u s reactor and

i r r a d i a t e d t h r o u g h a Vycor f i l t e r a t a m b i e n t t e m p e r a t u r e .

GLC a n a l y s i s o f a l i q u o t s r e v e a l e d t h a t t h e consumpt ion of

t h e l a c t o n e - 7 c e a s e d a f t e r 3 h r l e a v i n g - ca. 50% u n r e a c t e d .

A s w e l l a complex m i x t u r e o f p r o d u c t s dominated by two

p r o d u c t s , - 2 1 a n d 22, was p roduced i n t h e r a t i o of 44:56

which was c o n s t a n t t h r o u g h o u t t h e i r r a d i a t i o n . Extended

i r r a d i a t i o n i n c r e a s e d t h e c o m p l e x i t y o f t h e m i x t u r e . GLC

a n a l y s i s o f t h e i n i t i a l ( t i m e - 0 ) s a m p l e k e p t i n t h e d a r k

r e v e a l e d o n l y u n r e a c t e d s t a r t i n g materials .

2. Low T e m p e r a t u r e P h o t o l y s i s

A s o l u t i o n o f 0.369 g ( 3 . 7 6 m m o l , 1 .0 e q )

2 - p e n t e n o l i d e 1 .670 g (15 .0 mmol, 4.0 e q )

a - a c e t o x y a c r y l o n i t r i l e and 0.108 undecane i n 1 5 0 mL

a c e t o n i t r i l e was p l a c e d i n a Pyrex immers ion well, c o o l e d

t o - 3 0 0 ~ and i r r a d i a t e d t h r o u g h a Vycor f i l t e r . The

t e m p e r a t u r e o f t h i s s o l u t i o n s t a b i l i z e d a t -25% a f t e r 0 . 5

h r of i r r a d i a t i o n . GLC a n a l y s i s o f a l i q u o t s r e v e a l e d t h a t

t h e consumpt ion o f t h e l a c t o n e Z ceased a f t e r 4 h r of

i r r a d i a t i o n l e a v i n g - ca. 20% u n r e a c t e d .

The i r r a d i a t i o n was stopped a f t e r 5.5 h r and GLC

a n a l y s i s showed a complex m i x t u r e o f p r o d u c t s domina ted by

two p r o d u c t s , - 21 and - 22 i n t h e r a t i o o f 46:54, which was

f o u n d t o be c o n s t a n t t h r o u g h o u t t h e i r r a d i a t i o n . The

u s u a l workup and s h o r t p a t h d i s t i l l a t i o n y i e l d e d a n o i l

c o n t a i n i n g m a i n l y - 2 1 and - 22 c o n t a m i n a t e d w i t h t h e s t a r t i n g

l a c t o n e . F l a s h chromatography on s i l i c a gel y i e l d e d 0.215

g ( 2 7 % ) of a v i s c o u s y e l l o w o i l which GLC a n a l y s i s r e v e a l e d

t o be compr i sed of o n l y - 2 1 and - 22 i n a r a t i o o f 42:58.

T h i s m i x t u r e e x h i b i t e d o n l y o n e s p o t o n TLC u s i n g a

v a r i e t y of e l u a n t s . The s l i g h t predominance of one i s o m e r

38.17(C7, t r ) , 2 6 . 2 0 ( ~ 5 , t r ) , 26.07(C6, d ) 20.47(CH3, q);

ms(C1, i s o b u t a n e ) : 211(12 , M+2), 210(100 , M + 1 ) , 1 5 0 ( 5 4 ) .

Anal . ( o f m i x t u r e ) C a l c d . f o r CloH11N04:C, 57.41;

H , 5.30; N , 6.70. Found: C , 57.25; H , 5.36; N , 6.62.

G. P h o t o a d d i t i o n of acrylonitr i le t o 2 - b u t e n o l i d e ( 8 )

1. Ambient T e m p e r a t u r e P h o t o l y s i s

A s o l u t i o n o f 0.309 g ( 3 . 6 8 m m o l , 1.0 e q ) ,f 8

1 .56 g ( 2 9 . 4 m m o l , 8 .0 eq) a c r y l o n i t r i l e and 0.055 g

undecane i n 1 5 0 mL a c e t o n i t r i l e was p l a c e d i n a v y c o r

t o r u s reactor and i r r a d i a t e d a t a m b i e n t t e m p e r a t u r e . GLC

a n a l y s i s showed t h a t t h e l a c t o n e was consumed a f t e r 6.5

h r . A complex m i x t u r e of p r o d u c t s dominated by f o u r

p r o d u c t s 23, 24, - 25, - 26 i n t h e r a t i o o f 23:22:38:17 was

formed. The r a t i o o f t h e s e p r o d u c t s was c o n s t a n t

t h r o u g h o u t t h e i r r a d i a t i o n . GLC a n a l y s i s of t h e i n i t i a l

( t i m e l o ) s a m p l e k e p t i n t h e d a r k showed o n l y u n r e a c t e d

s t a r t i n g materials by GLC. The u s u a l workup and s h o r t p a t h

d i s t i l l a t i o n y i e l d e d 0.232 g of a v i s c o u s o i l which

e x h i b i t e d two s p o t s on TLC. F l a s h chromatography on

S i l i c a G e l u s i n g 1:l EtOAc/Hexane s e p a r a t e d t h e m i x t u r e

i n t o two f r a c t i o n s , e a c h o f which c r y s t a l l i z e d o n s t a n d i n g

and were r e c r y s t a l l i z e d f rom EtOH. F r a c t i o n 1, 0.098

g ( 1 9 % ) , mop. 79-92% was a 68:32 m i x t u r e o f - 23 and - 24.

F r a c t i o n 2, 0 .103 g ( 1 0 % ) , m.p. 80-84OC was a 55:45 m i x t u r e

of - 25 and - 26 by GLC analysis. Single crystals of each

mixture were grown from an EtOAc/Hexane solution and

analysed by X-Ray crystallography39. GLC analysis of the

crystals subsequently identified 23 as

cis-exo-7-cyano-3-oxabicyclo [3.2.0]heptan-2-one and 25 as -- - cis-endo-7-cyano-3- oxabicyclo [3.2.0lheptan-2-one. --

Ir(KBr pellet) of mixture of 23 and 24: 2240(w),

1760(~), 1470(~), 1440(w), 1380(m), 1260(m), 1180(s),

1120(w), lO6O(m), 98O(m), 96O(w), 800(w) cm-l.

Anal. (of mixture) Calcd. for C7H7N02: C, 61.31; H,

5.14; N, 10.22. Found: C, 61.21; H,5.31; N,10.07.

Ir(KBr pellet 1 of mixture of - 25 and - 26: 2240(w)

Anal. ( o f m i x t u r e ) C a l c d . f o r C7H7N02: C, 61.31; H ,

5.14; N , 10 .22 . Found: C , 61.35; H I 5.35; N , 10.06.

2. Low T e m p e r a t u r e P h o t o l y s i s

A s o l u t i o n o f 0.318 g ( 3 . 7 8 mmol, 1 . 0 e q ) - 8 , 1 .611 g

(30 .4 mmol, 8 .0 e q ) a c r y l o n i t r i l e and 0,075 g undecane

i n 150 mL a c e t o n i t r i l e was p l a c e d i n a Pyrex immersion

well, c o o l e d t o -30% and i r r a d i a t e d t h r o u g h a Vycor

f i l t e r . The t e m p e r a t u r e s t a b i l i z i e d a t -20•‹c a f t e r

0.5 h r of i r r a d i a t i o n . GLC a n a l y s i s of a l i q u o t s r e v e a l e d

t h a t t h e l a c t o n e - 8 was consumed i n 1 . 5 h r and t h a t a

complex m i x t u r e o f p r o d u c t s domina ted by t h e same f o u r

p r o d u c t s (24-26) -- o b s e r v e d a b o v e was formed, The r a t i o o f

t h e f o u r p r o d u c t s was 23:19:42:15 and t h i s r a t i o was

c o n s t a n t t h r o u g h o u t t h e i r r a d i a t i o n . The u s u a l workup

and s h o r t p a t h d i s t i l l a t i o n g a v e a c r u d e y e l l o w o i l which

was p r e d o m i n a n t l y composed o f t h e f o u r p h o t o a d d u c t s .

F l a s h ch romatography o n s i l i c a g e l as b e f o r e s e p a r a t e d

t h e f o u r p r o d u c t s f rom t h e h o s t o f b y p r o d u c t s t o g i v e ,

a f t e r s h o r t p a t h d i s t i l l a t i o n , a v i s c o u s y e l l o w o i l which

weighed 0.206 g ( 4 0 % ) .

3. S o l v e n t S t u d i e s - I r r a d i a t i o n o f 8 and

A c r y l o n i t r i l e i n E t h e r a t Ambient Tempera ture

A s o l u t i o n of 0.237 g ( 2 . 8 2 mmol, 1 .0 e q ) - 8, 1.199 g

(22 .6 mmol, 8.0 eq) a c r y l o n i t r i l e and 0.074 g undecane i n

1 5 0 mL anhyd. e t h e r was p l a c e d i n a Vycor t o r u s r e a c t o r

and i r r a d i a t e d a t a m b i e n t t e m p e r a t u r e . GLC a n a l y s i s o f

a l i q u o t s r e v e a l e d t h a t t h e l a c t o n e 2 was consumed a f t e r

3.5 h r o f i r r a d i a t i o n and t h a t a complex m i x t u r e of

p r o d u c t s was formed. Mixed sample GLC e x p e r i m e n t s showed

t h a t compounds - 2 3 and - 25 were p r e s e n t as minor components

o f t h e m i x t u r e and t h a t compounds 24 and 26 were a b s e n t .

GLC a n a l y s i s of t h e i n i t i a l ( t i m e = O ) sample k e p t i n t h e

d a r k r e v e a l e d o n l y u n r e a c t i n g s t a r t i n g materials.

4 . S o l v e n t S t u d i e s - I r r a d i a t i o n o f 8 and

A c r y l o n i t r i l e i n E t h e r a t Low Tempera ture

A s o l u t i o n o f 0.221 g ( 2 . 6 3 mmol, 1 . 0 e q ) - 8, 1 .113 g

( 2 1 . 1 mmol, 8.0 e q ) a c r y l o n i t r i l e and 0.063 g undecane i n

1 5 0 mL anhyd. e t h e r was p l a c e d i n a Pyrex immersion w e l l ,

c o o l e d t o -30% and i r r a d i a t e d t h r o u g h a Vycor f i l t e r .

GLC a n a l y s i s of a l i q u o t s r e v e a l e d t h a t t h e l a c t o n e - 8 was

consumed w i t h i n 3 h r and a complex m i x t u r e was formed.

Mixed sample GLC r e v e a l e d t h a t - 2 3 and 2 were p r e s e n t as

minor components o f t h e m i x t u r e and t h a t 24 and - 2 6 were

p r e s e n t as t r a c e components .

5. At tempted Base I s o m e r i z a t i o n o f 2 3 and 24 w i t h N a O E t

To a s o l u t i o n o f 0.12 g of t h e ch romatography

f r a c t i o n 1, o b t a i n e d i n t h e f i r s t e x p e r i m e n t i n t h i s

ser ies , S e c t i o n G 1 above , c o n t a i n i n g compounds - 23 and - 24

i n t h e r a t i o o f 68:32 and 0.009g u n d e c a n e i n 1 0 mL anhyd.

e t h a n o l was added 1 . 5 mL 1.2 M NaOEt. The r e s u l t i n g

s o l u t i o n s t i r r e d a t ambien t t e m p e r a t u r e f o r 1 h r . The

u s u a l workup and GLC a n a l y s i s r e v e a l e d t h e d i s a p p e a r a n c e

of 23 and 24 and t h e f o r m a t i o n o f a h o s t o f h i g h e r b o i l i n g

compounds. A sample of t h e c h r o m a t o g r a p h y f r a c t i o n 2 was

t r e a t e d i n a s imi lar manner and a l s o r e s u l t e d i n loss of

t h e sample as well as f o r m a t i o n of a h o s t of h i g h e r

b o i l i n g compounds.

6. At tempted Base I s o m e r i z a t i o n o f 2 3 and 24 w i t h KOtBu

To a s o l u t i o n o f 0.015 g of t h e ch romatography

f r a c t i o n 1, c o n t a i n i n g compounds - 23 and - 24 i n t h e r a t i o o f

68:32, 0.020 g undecane and 0.15 mL HMPA i n 1 0 mL d r y

t -Bu tano l was added 0.106 g p o t a s s i u m t - b u t o x i d e and t h i s

m i x t u r e s t i r r e d a t room t e m p e r a t u r e f o r 2 h r . The u s u a l

workup and GLC a n a l y s i s r e v e a l e d no change or

d e c o m p o s i t i o n o f f r a c t i o n 1. T h i s p r o c e d u r e was r e p e a t e d

w i t h a sample o f t h e chromatography f r a c t i o n 2 w i t h

i d e n t i c a l r e s u l t s .

7. Attempted Alumina I s o m e r i z a t i o n o f 23 and 24

A 0.10 g sample of t h e ch romatography f r a c t i o n 1 was

e l u t e d t h r o u g h a 2.0 g column o f n e u t r a l Alumina w i t h

30 mL CHC13 as b e f o r e and r e c o v e r e d unchanged. A sample

o f t h e ch romatography f r a c t i o n 2 was t r e a t e d i n a n

i d e n t i c a l manner and s i m i l a r l y r e c o v e r e d unchanged. The

1~ nmr s p e c t r a o f t h e m i x t u r e s was i d e n t i c a l t o spectra

o b t a i n e d b e f o r e t r e a t m e n t .

H. P h o t o a d d i t i o n of a - c h l o r o a c r y l o n i t r i l e t o

2 - b u t e n o l i d e ( 8 )

1. Ambient Tempera tu re P h o t o l y s i s

A s o l u t i o n o f 0.465 g ( 5 . 5 5 mmol, 1 . 0 eq)

2 - b u t e n o l i d e , 4.94 g (56 .5 mmol, 1 0 e q )

a - c h l o r o a c r y l o n i t r i l e and 0.105 g undecane i n 200 mL .

a c e t o n i t r i l e was p l a c e d i n a Pyrex immersion well and

i r r a d i a t e d t h r o u g h a Vycor f i l t e r a t ambien t t e m p e r a t u r e .

GLC a n a l y s i s o f a l i q u o t s r e v e a l e d t h a t t h e consumpt ion o f

t h e l a c t o n e - 8 c e a s e d a f t e r 2 h r o f i r r a d i a t i o n l e a v i n g H. 80% u n r e a c t e d . T h i s was accompanied by f o r m a t i o n o f a

complex m i x t u r e o f p r o d u c t s . Extended i r r a d i a t i o n

i n c r e a s e d t h e c o m p l e x i t y o f t h e m i x t u r e b u t d i d n o t r e s u l t

i n f u r t h e r consumpt ion of t h e l a c t o n e . GLC a n a l y s i s o f

t h e i n i t i a l ( t i m e = O ) sample kept i n t h e d a r k r e v e a l e d o n l y

u n r e a c t e d s t a r t i n g m a t e r i a l s . A f t e r 8 h r of i r r a d i a t i o n

the usual workup followed by shortpath distillation, bulb

temperature 105-1200/25 torr, yielded 0.302 g( 65%) of

2-butenolide which was 93% pure by GLC.

2. Low Temperature Photolysis

A solution of 0.535 g(6.35 mmol, 1.0 eq)

2-butenolide, 4.42 g(50.5 mmol, 8.0 eq)

a-chloroacrylonitrile and 0.092 g undecane in 200 mL

acetonitrile was placed in a Pyrex immersion well, cooled

to -400C and irradiated through a Vycor filter. The

temperature of the solution stabilized at -25% after 1

hr. GLC analysis of aliquots revealed the consumption of

the lactone - 8 ceased after 3 hr of irradiation leaving ca. - 70% unreacted accompanied by formation of a complex

mixture of products. After 4 hr of irradiation the usual

workup followed by shortpath distillation, bulb

temperature 105-1150C/24 torr, gave 0.284 g(53%) of

2-butenolide, which was 94% pure by GLC.

I. Photoaddition of a-acetoxyacrylonitrile to

2-butenolide ( 8)

1. Ambient Temperature Photolysis

A solution of 0.550 g(6.54 mmol, 1.0 eq)

2-butenolide, 3.61 g(22.5 mmol, 5.0 eq)

a-acetoxyacrylonitrile and 0.112 g undecane in 150 mL

a c e t o n i t r i l e was p l a c e d i n a Vycor t o r u s r e a c t o r and

i r r a d i a t e d a t a m b i e n t t e m p e r a t u r e . GLC a n a l y s i s r e v e a l e d

t h a t consumpt ion of t h e l a c t o n e - 8 c e a s e d a f t e r 3 h r ,

l e a v i n g - ca. 70% u n r e a c t e d accompanied by f o r m a t i o n of a

complex m i x t u r e o f p r o d u c t s . Ex tended i r r a d i a t i o n

i n c r e a s e d t h e c o m p l e x i t y o f t h e m i x t u r e . The u s u a l workup

and s h o r t p a t h d i s t i l l a t i o n a f t e r 6 h r o f i r r a d i a t i o n gave

0.247 g ( 4 5 % ) o f l a c t o n e which was 93% p u r e by GLC.

GLC a n a l y s i s o f t h e i n i t i a l ( t i m e = O ) s ample k e p t i n t h e

d a r k r e v e a l e d o n l y u n r e a c t e d s t a r t i n g materials.

2. Low TemDerature P h o t o l v s i s

A s o l u t i o n of 0.445 g ( 5 . 3 1 m m o l , 1 . 0 e q )

2 - b u t e n o l i d e , 2.95 g ( 2 6 . 5 mmol, 5.0 e q )

a - a c e t o x y a c r y l o n i t r i l e and 0.097 g undecane i n 20 mL

a c e t o n i t r i l e was p l a c e d i n a P y r e x immers ion well, c o o l e d

t o -30•‹C and i r r a d i a t e d t h r o u g h a Vycor f i l t e r . The

t e m p e r a t u r e o f t h e s o l u t i o n s t a b i l i z e d a t -200C a f t e r one

h o u r of i r r a d i a t i o n . GLC a n a l y s i s o f a l i q u o t s r e v e a l e d

t h a t t h e consumpt ion o f t h e l a c t o n e - 8 c e a s e d a f t e r 2.5 h r

l e a v i n g - c a . 70% u n r e a c t e d . T h i s was accompanied by

f o r m a t i o n o f a complex m i x t u r e o f p r o d u c t s . A f t e r f o u r

h o u r s of i r r a d i a t i o n t h e u s u a l workup and s h o r t p a t h

d i s t i l l a t i o n gave 0.227 g ( 5 1 % ) o f l a c t o n e - 8 which was 94%

p u r e by GLC.

J. P h o t o a d d i t i o n of A c r y l o n i t r i l e t o

3,4,4-trimethyl-2-buten-1,4-olide ( 9 )

1. Ambient Tempera tu re P h o t o l y s i s

A s o l u t i o n o f 0.112 g ( . 8 8 7 mmol, 1 .0 e q ) 9, 0.387 g

(7 .18 mrnol, 8.0 e q ) a c r y l o n i t r i l e and 0.038 g undecane i n

1 5 0 mL a c e t o n i t r i l e was p l a c e d i n a Vycor t o r u s r e a c t o r

and i r r a d i a t e d a t ambien t t e m p e r a t u r e . GLC a n a l y s i s o f

a l i q u o t s r e v e a l e d t h a t t h e l a c t o n e was consumed a f t e r

1 . 5 h r o f i r r a d i a t i o n and t h a t a complex m i x t u r e dominated

by f o u r p r o d u c t s 27, - 28, - 29 and - 30, i n t h e r a t i o o f

27: 26: 32: 1 5 , was formed. T h i s r a t i o was c o n s t a n t

t h r o u g h o u t t h e i r r a d i a t i o n . A f t e r 2 h r o f i r r a d i a t i o n t h e

u s u a l workup and s h o r t p a t h d i s t i l l a t i o n gave 0.124 g ( 7 8 % )

o f a v i s c o u s y e l l o w o i l which GLC a n a l y s i s r e v e a l e d t o b e

a 92% p u r e m i x t u r e of t h e f o u r p r o d u c t s -- 27-30.

2. Low Tempera tu re P h o t o l y s i s

A s o l u t i o n of 1 .85 g(1 .47 mmol, 1 . 0 e q ) 9, 0.630 g

(11.9 mmol, 8 . 1 e q ) a c r y l o n i t r i l e and 0.063 g undecane i n

1 5 0 mL a c e t o n i t r i l e was p l a c e d i n a Pyrex immers ion w e l l ,

c o o l e d t o - 3 0 0 ~ and i r r a d i a t e d t h r o u g h a Vycor f i l t e r .

The t e m p e r a t u r e o f t h e s o l u t i o n s t a b i l i z e d a t -20% a f t e r

0 .5 h r of i r r a d i a t i o n . GLC a n a l y s i s of a l i q u o t s r e v e a l e d

t h a t t h e l a c t o n e was consumed a f t e r 2 h r of i r r a d i a t i o n

and a complex m i x t u r e domina ted by -- 27-30 was formed.

The r a t i o of t h e f o u r p r o d u c t s was found t o be 19:39:27:20

and t h i s r a t i o was found t o b e c o n s t a n t t h r o u g h o u t t h e

i r r a d i a t i o n . After 2.5 h r of i r r a d i a t i o n t h e u s u a l workup

and s h o r t p a t h d i s t i l l a t i o n g a v e 0.232 g ( 8 1 % ) of a v i s c o u s

y e l l o w o i l which GLC a n a l y s i s r e v e a l e d t o be a 92% p u r e

m i x t u r e o f -- 27-30 i n t h e r a t i o o f 19:35:25:20. T h i s

material e x h i b i t e d two s p o t s on TLC u s i n g EtOAc/toluene

1:l and r e p e a t e d f l a s h ch romatography o n s i l i c a g e l

s e p a r a t e d o n l y 0.029 g ( 1 0 % ) of - 30 f rom t h e m i x t u r e . T h i s

material was i s o l a t e d as a n o i l which c r y s t a l l i z e d o n

s t a n d i n g , mop. 97-100•‹C and was 97% p u r e by GLC. The

t h r e e o t h e r components g a v e a s i n g l e spot by TLC b u t

s e v e r a l c h r o m a t o g r a p h i c f r a c t i o n s c o n t a i n e d d i f f e r e n t

relative amounts of each product present , making

a s s i g n m e n t o f t h e s i g n a l s i n t h e 1% nmr s p e c t r a

p o s s i b l e . The s i g n a l s i n t h e 1~ nmr s p e c t r a of t h e

m i x t u r e were n o t amenable t o a n a l y s i s d u e t o o v e r l a p p i n g

s i g n a l s .

24.2(CH3), 1 9 . 8 ( C ~ ~ ) , 14.4(CH3); rns(~1, i s o b u t a n e ) :

1 8 0 ( 1 0 0 , M+l) , 9 5 ( 7 ) .

Anal . o f m i x t u r e . Ca lcd . f o r CloH18NO: C, 67.02;

3. A t t empted Alumina I s o m e r i z a t i o n o f 27-30

A 0.012 g s a m p l e of t h e d i s t i l l e d m i x t u r e c o n t a i n i n g

27-30 i n t h e r a t i o o f 19:35:26:20 by GLC was e l u t e d -- t h r o u g h a 2 g co lumn o f n e u t r a l Alumina as b e f o r e .

Removal o f t h e s o l v e n t l e f t 0.011 g of material which

GLC a n a l y s i s r e v e a l e d t o be -- 27-30 i n t h e same r a t i o as

b e f o r e t r e a t m e n t . A 0.006 g sample of 2 was t r e a t e d

i n t h e same manner and r e c o v e r e d unchanged a s w e l l .

4. At t empted ~ h o t o i s o m e r i z a t i o n 27-30

A s o l u t i o n of 0.017 g of a c h r o m a t o g r a p h i c f r a c t i o n

c o n t a i n i n g -- 27-30 i n t h e r a t i o of 21:25:40:14 by GLC and

0.009 g undecane i n 1 0 mL a c e t o n i t r i l e was p l a c e d i n a

q u a r t z t es t t u b e , t a p e d t o t h e s i d e o f t h e lamp j a c k e t and

i r r a d i a t e d t h r o u g h a Vycor f i l t e r a t ambien t t e m p e r a t u r e

f o r 2 h r . GLC a n a l y s i s o f t h e s o l u t i o n a f t e r i r r a d i a t i o n

r e v e a l e d n o change i n t h e r e l a t i v e amounts of t h e f o u r

p r o d u c t s .

K. P h o t o a d d i t i o n of a - c h l o r o a c r y l o n i t r i l e t o

1. Ambient Tempera tu re P h o t o l y s i s

A s o l u t i o n o f 0.122 g ( . 9 6 7 m m o l , 1 . 0 e q ) 2, 0.630 g

(7 .2 mmol, 7.4 e q ) a - c h l o r o a c r y l o n i t r i l e and 0.051 g

undecane i n 1 5 0 mL a c e t o n i t r i l e was p l a c e d i n a Vycor

t o r u s r e a c t o r and i r r a d i a t e d a t a m b i e n t t e m p e r a t u r e . GLC

a n a l y s i s o f a l i q u o t s r e v e a l e d t h e consumpt ion of t h e

l a c t o n e - 9 c e a s e d a f t e r two h r l e a v i n g G. 90% u n r e a c t e d .

T h i s was accompanied by f o r m a t i o n o f a complex m i x t u r e of

h i g h e r b o i l i n g p r o d u c t s . Extended i r r a d i a t i o n d i d n o t

r e s u l t i n f u r t h e r consumpt ion of t h e s t a r t i n g l a c t o n e ,

o n l y an i n c r e a s e i n t h e c o m p l e x i t y o f t h e m i x t u r e . GLC

a n a l y s i s of t h e i n i t i a l ( t i m e = O ) s a m p l e k e p t i n t h e d a r k

c o n t a i n e d o n l y u n r e a c t e d s t a r t i n g m a t e r i a l s . The u s u a l

work up and s h o r t p a t h d i s t i l l a t i o n , b u l b t e m p e r a t u r e

9 0 - 1 0 5 0 ~ / 1 0 t o r r , g a v e 0.098 g ( 7 8 % ) o f 9 which was 97%

p u r e by GLC.

2. Low T e m p e r a t u r e P h o t o l y s i s

A s o l u t i o n o f 0.116 g(0 .919 mmol, 1 . 0 e q ) 2, 0.483 g

(5 .52 mmol, 5 .0 e q ) a - c h l o r o a c r y l o n i t r i l e and 0.075 g

undecane i n 200 mL a c e t o n i t r i l e was p l a c e d i n a Pyrex

immers ion well, c o o l e d t o -30% and i r r a d i a t e d t h r o u g h a

Vycor f i l t e r . The t e m p e r a t u r e of t h e s o l u t i o n s t a b i l i z e d

a t -20% a f t e r 0 .5 h r i r r a d i a t i o n . GLC a n a l y s i s o f

a l i q u o t s r e v e a l e d t h a t t h e consumpt ion o f t h e l a c t o n e - 9

c e a s e d a f t e r 2 .5 h r o f i r r a d i a t i o n l e a v i n g - ca. 85%

u n r e a c t e d accompanied by t h e f o r m a t i o n o f a complex

m i x t u r e o f h i g h e r b o i l i n g p r o d u c t s . A f t e r 3 h r o f

i r r a d i a t i o n t h e u s u a l workup and s h o r t p a t h d i s t i l l a t i o n

gave 0.083 g ( 7 2 % ) o f - 9 which was 96% p u r e by GLC.

L. Photoaddition of a-acetoxyacrylonitrile to 9

1. Ambient T e m p e r a t u r e P h o t o l y s i s

A s o l u t i o n o f 0.098 g ( . 7 8 mmol, 1 .0 e q ) 2, 0.431 g

(3 .88 mmol, 5 .0 e q ) a - a c e t o x y a c r y l o n i t r i l e and 0.062 g

undecane i n 200 mL a c e t o n i t r i l e was p l a c e d i n a Pyrex

immersion w e l l and i r r a d i a t e d th rough a Vycor f i l t e r a t

a m b i e n t t e m p e r a t u r e . GLC a n a l y s i s o f a l i q u o t s r e v e a l e d

consumpt ion of l a c t o n e 9 c e a s e d a f t e r 1 . 5 h r l e a v i n g ca. - - 90% u n r e a c t e d . T h i s was accompanied by f o r m a t i o n of

complex m i x t u r e o f h i g h e r b o i l i n g p r o d u c t s . GLC a n a l y s i s

o f t h e i n i t i a l ( t i m e = O ) s ample k e p t i n t h e d a r k showed

o n l y u n r e a c t e d s t a r t i n g materials. The u s u a l workup and

s h o r t p a t h d i s t i l l a t i o n g a v e 0.077 g ( 7 9 % ) 9 which was 94%

p u r e by GLC.

2. Low T e m p e r a t u r e P h o t o l y s i s

A s o l u t i o n o f 0.093 g ( . 7 4 mmol, 1 . 0 eq) 9, 0.383 g - (3 .54 mmol, 4.8 eq) a - a c e t o x y a c r y l o n i t r i l e and 0.061 g

undecane i n 200 mL a c e t o n i t r i l e was p l a c e d i n a Pyrex

immersion well, c o o l e d t o -30•‹c a n d i r r a d i a t e d t h r o u g h a

Vycor f i l t e r . The t e m p e r a t u r e o f t h e s o l u t i o n s t a b i l i z e d

a t -200C a f t e r 0 .5 h r i r r a d i a t i o n . GLC a n a l y s i s o f

a l i q u o t s r e v e a l e d c o n s u m p t i o n o f l a c t o n e 9 ceased a f t e r

2.0 h r o f i r r a d i a t i o n l e a v i n g ca. 80% u n r e a c t e d . T h i s was - accompanied by t h e f o r m a t i o n o f a complex m i x t u r e of

p r o d u c t s . A f t e r 3 h r of i r r a d i a t i o n t h e u s u a l workup and

s h o r t p a t h d i s t i l l a t i o n g a v e by 0 .63 g ( 6 8 % ) - 9 which was 94%

p u r e by GLC.

S e n s i t i z e r Experiments

n. I r r a d i a t i o n of A c r y l o n i t r i l e and its a-chloro

and a-acetoxy d e r i v a t i v e s i n Acetone

1. A so lu t i on of 1 .116 g(21.0 mmol) a c r y l o n i t r i l e i n

150 mL spec. grade acetone was placed i n a Vycor to rus

r eac to r and i r r a d i a t e d through a Corex f i l t e r a t ambient

temperature.

The s o l u t i o n turned yellow wi th in 0.5 hr . GLC

ana ly s i s of a l i q u o t s withdrawn a t regular i n t e r v a l s

revealed t h e formation of a complex mixture of low bo i l ing

products . GLC ana ly s i s of t he i n i t i a l (time=O) sample

kept i n t he dark d i d not show any of these products.

2. A so lu t i on of 1.005 g(11.5 mmol)

a -ch lo roacry lon i t r i l e i n 150 mL spec. grade acetone was

placed i n a Vycor t o r u s r eac to r and i r r a d i a t e d through a

Corex f i l t e r a t ambient temperature. The s o l u t i o n began

d i sco lour ing wi th in 15 min. and GLC ana lys i s revealed c

formation of a complex mixture of low bo i l ing products.

GLC ana ly s i s of t h e i n i t i a l (time=O) sample kept i n the

dark d i d not contain any of these products.

3. A so lu t i on of 1.156 g(10.4 mmol)

a-acetoxyacryloni t r i le and 0.104 g decane i n 150 mL spec.

grade acetone was placed i n a Vycor t o ru s reac tor and

i r r a d i a t e d through a Corex f i l t e r a t ambient temperature.

T h i s s o l u t i o n began d i sco lour ing immediately on

i r r a d i a t i o n and GLC ana ly s i s revealed a decrease i n the

r e l a t i v e amount of a -ace toxyacry lon i t r i l e accompanied

by formation of a complex mixture of products. A l l

t h e o l e f i n was consumed wi th in 2 h r of i n i t i a t i o n of

i r r a d i a t i o n . GLC ana ly s i s of t he i n i t i a l (time=O)

sample kept i n t he dark showed only unreacted s t a r t i n g

mate r ia l s .

I r r a d i a t i o n of Ac ry lon i t r i l e , a - ch lo roac ry lon i t r i l e

and a -ace toxyacry lon i t r i l e i n t h e presence of - Acetophenone

1. A so lu t i on of 1.060 g(8.86 mmol, 1 . 0 eq )

acetophenone, 2.350 g(44.3 mmol, 5.0 eq) a c r y l o n i t r i l e and

0.101 g undecane i n 150 mL a c e t o n i t r i l e was placed i n a

Vycor t o ru s reac to r and i r r a d i a t e d through a Corex f i l t e r

a t ambient temperature. T h i s s o l u t i o n began d i sco lour ing

immediately and GLC ana ly s i s of a l i q u o t s withdrawn a t

regular i n t e r v a l s revealed a decrease i n t he amount of

acetophenone accompanied by formation of a complex mixture

of products. The consumption of t h e acetophenone ceased

a f t e r 2.5 hr of i r r a d i a t i o n leaving - ca. 40% unreacted.

GLC ana lys i s of the i n i t i a l (time=O) sample kept i n t he

dark showed only unreacted s t a r t i n g mate r ia l s .

2. A so lu t ion of 1 . 2 1 2 g (10 .1 mmol, 1 . 0 eq)

acetophenone, 4 . 4 1 g (50.4 mmol, 5.0 eq)

a-chloroacryloni t r i le and 0.098 g undecane i n 150 mL

a c e t o n i t r i l e was placed i n a Vycor torus reactor and

i r radiated through a Corex f i l t e r a t ambient temperature.

The solution began discolouring immediately on i r rad ia t ion

and GLC analysis of a l iquots showed a decrease i n the

amount of acetophenone accompanied by formation of a

complex mixture of products. The consumption of the

acetophenone ceased a f t e r 2 hr of i r r ad ia t ion leaving ca. - 50% unreacted. GLC analysis of the i n i t i a l (time-0)

sample kept i n the dark showed only unreacted s t a r t i n g

materials .

3 . A so lu t ion of 1.175 g(9.78 mmol, 1.0 eq)

acetophenone, 5.32 g(47.9 mmol, 4.9 eq)

a-acetoxyacrylonitr i le and 0.097 g undecane i n 150 mL

a c e t o n i t r i l e was placed i n a Vycor torus reactor and

i r radiated through a Corex f i l t e r a t ambient temperature.

The solution began discolouring immediately on i r r ad ia t ion

and GLC analysis of a l iquots revealed a decrease i n both

the amounts of acetophenone and a-acetoxyacrylonitrile

accompanied by formation of a complex mixture of

products. The decrease i n the r e l a t ive amounts of

a-acetoxyacrylonitr i le and acetophenone ceased a f t e r

1.5 hr of i r r ad ia t ion leaving ca. 60% and 40% unreacted -

and a-acetoxyacrylonitrile in the presence of

Hexamethylbenzene

1. A solution of 1.135 g(6.9 mmol, 1.0 eq)

hexamethylbenzene, 1.891 g(35.7 mmol, 5.1 eq)

acrylonitrile and 0.078 g undecane in 150 mL acetonitrile

was placed in a Vycor torus reactor and irradiated through

a Corex filter at ambient temperature. The solution began

discolouring immediately on irradiation and GLC analysis

of aliquots revealed a decrease in the amount of

hexamethylbenzene accompanied by formation of complex

mixture of products. The consumption of the

hexamethylbenzene ceased after 1.5 hr of irradiation

leaving - ca. 60% unreacted. GLC analysis of the initial . (time=O) sample kept in the dark revealed only unreacted

starting materials.

2. A solution of 1.032 g(6.36 mmol, 1.0 eq)

hexamethylbenzene, 2.783 g(31.8 mmol, 5.0 eq)

a-Chlor~acrylonitrile and 0.082 g undecane in 150 mL

acetonitrile was placed in a Vycor torus reactor and

irradiated through a Corex filter at ambient temperature. .

The solution began I discolouring immediately on irradiation

and GLC analysis revealed a decrease in the amount of

hexamethylbenzene and the formation of a complex mixture

of products. The consumption of the hexamethylbenzene

ceased after 2 hr of irradiation leaving - ca. 70%

unreacted. GLC analysis of the initial (time=O) sample

kept in the dark contained only unreacted starting

materials.

3. A solution of 1.020g(6.06 mmol, 1.0 eq)

hexamethylbenzene, 3.301 g(29.7 mmol, 4.9 eq)

a-acetoxyacrylonitrile and 0.076 g undecane in 150 mL

acetonitrile was placed in a Vycor torus reactor and

irradiated through a Corex filter at ambient temperature.

The solution began discolouring immediately on irradiation

and GLC analysis of aliquots revealed a decrease in both

the amounts of a-acetoxyacrylonitrile and

hexamethylbenzene as well as formation of a complex

mixture of products. The consumption of the c

a-acetoxyacrylonitrile and hexamethylbenzene ceased after

2 hr of irradiation leaving - ca. 70% and 50% respectivelY

of these components unreacted. GLC analysis of the

initial (time=O) sample kept in the dark revealed only

unreacted starting materials.

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