PRACTICE QUESTIONS FOR FINAL EXAM — CEM 252 SUMMER

1. (25 pts) Simple syntheses: In the boxes provided, draw the major organic products for each

of the following reactions (5 pts each).

OH 1) H2SO4/

Na2Cr2O72) Zn(Hg)/HCl

i.

OH

ii.

iii.

iv.

O

OH 1) SOCl22) Et2CuLi3) H3O+

v.

O

NH2

NaBH3CN

Acetic acid

O O

Opyridine

CH3COCl/AlCl3NH

O

Gord o

aEI EITEL

demyeenasey Pandit 5

iii ex EeoIHn.EeEIi so.IS

e imine 3pt amine

Etjn

Ior EEIII

Tea T.IEIterate00 toEst't off't't

T 9

2. (35 pts) Reactions and mechanisms of amines:

(a) (5 pts) In the box, draw the intermediate in this two-step amine synthesis:

(b) (6 pts) In the boxes, draw simple examples of the requested compound types:

(c) (24 pts) Draw the intermediates (3 pt each) in the dotted boxes below and add arrows to show the mechanism for the imine-forming reaction of cyclohexanone with ethylamine. Be sure to include arrows (1 pt each) to move electrons. Ethylamine is the nucleophilic reagent, while EtNH3+/EtNH2 is the acid/base set for proton transfer.

Br NaCNEthanolsolvent

H2/Ptor1. LiAlH4/ether2. H2O

NH2

A secondary amine A tertiary alcoholA quaternary ammonium ion

O H2N

Protonation

HO NH

Loss of Leaving group

–H2O

N

H3N+ H2OH2N+

Nucleophilicattack

H2NH

DeprotonationH2N

Protonation

H2NH

N

DeprotonationH2N

Product Imine

Cyclohexanone Ethylamine N-ethylcyclohexanimine

ctivated

g.at nEz ea 50pA

TE E Is

en f w

E'Eign E 2I 2Magento

a 43 EEF

to

zky.oHit Hgtftp.t it't aIt

(a) (6 pts) Consider the three pairs of structures below. Are they resonance structures, tautomers or different formulas (circle your answer), 2 pts each.

2. (10 pts) Extra credit: Igor's Errors: Igor, your clumsy lab assistant, attempts to earn your favor by running extra reactions at night, without your advice. In each case, the reactions fail. Shown below are five of his failures, showing reagents, conditions, and the product he had intended to form. For each case, write just one or two sentences to explain what went wrong in the box at right. If you can identify a problem intermediate or product that formed instead of the desired material, draw it along with your explanation.

OH O

N

O

N

O

H HResonance structuresTautomersDifferent formulas

Resonance structuresTautomersDifferent formulas

NH2

O

N

O

HResonance structuresTautomersDifferent formulas

CN

CN

+ FAIL!Heat(Diels-Alder)

CN

CN

FAIL!1)HNO3/H2SO42) NaOH/H2O

NH2 NH2

NO2

FAIL!Ether

NH + xs CH3I NCH3CH3

I

FAIL!1) Mg/ether2) H3O+

HO

OBr

O

FAIL!SN2 Williamsonethersynthesis

Cl

+ EtO Na

OEt

I Tfo low IH HH H

for fveA 0 If itµ SE e

w r Mit O

gOA

KYAH

endb v

Evs trans diene cannot

4k be in S cis dieselst feet

eledwnwiearao.byt8YTnzsefedMmetadonatt IND eThe line pairs ofelation0 is in Thearomatic8188kmso not available for gµz

No reef

Is EEEn9Br g atwoPka E µSPI can'tdo SN2 an an 0

spa cartons Br

3. (10 pts, 1 pt. each) For the following transformations (i-x), choose the appropriate letter from

the "reagent shelf" below. Each box only gets one letter. If needed, you may use the same reagent more than once.

PPh3

NH2

O

N

H H

OH

N

OH

N

OO S S

OH

EtO OEt

C)

1. LiAlH42. H2O

HSSH

A)[H+]

B)

HOOH

D)H+

NH2OH

[H+]G)

1. H2N-NH2 / H+

2. KOH/H2O/heat

E)H+

F)

H)

RCO3H

MgBr

HN

K)

NaCr2O7H2SO4/H2O

I)H+

J)

L)2. H2O

EtOH

[H+]

1.

iii

iii

iv

vi

viii

x

ix

v

vii

I

is acIenami

aµ Il GiViii F dH E I fX L

dO r p

I