TRIPHENYLPHOSPHINE DICHLORIDE 1

Triphenylphosphine Dichloride1

Ph3PCl3

[2526-64-9] C18H15Cl2P (MW 333.20)InChI = 1/C18H15Cl2P/c19-21(20,16-10-4-1-5-11-16,17-12-

6-2-7-13-17)18-14-8-3-9-15-18/h1-15HInChIKey = ASWXNYNXAOQCCD-UHFFFAOYAC

(conversion of alcohols,6–10 phenols,13 and enols15 into alkylchlorides; synthesis of vic-dichlorides16 or chlorohydrins17 fromepoxides; conversion of carboxylic acids11 and derivatives20 intoacyl chlorides; chlorination23,24 or dehydration11 of the CONHgroup; production of iminophosphoranes from amines and related

compounds27–29)

Alternate Names: dichlorotriphenylphosphorane; triphenyl-dichlorophosphorane; chlorotriphenylphosphonium chloride.

Physical Data: adduct:2 white crystalline solid; mp 85–100 ◦C;4

fp 20 ◦C. Ph3P: mp 80.5 ◦C; bp 377 ◦C (in inert gas); d254

1.194 g mL−3; n80D 1.6358. Cl2: mp −101 ◦C; bp −34.6 ◦C; d0

3.214 g L−1.Solubility: adduct: slightly sol ether, THF, PhMe; sol CCl4,

CH2Cl2, DMF, MeCN, pyridine; insol petroleum ether. Ph3P:sol ether, PhH, CHCl3, AcOH; less sol alcohol; pract insol H2O.Cl2: sol CCl4, alcohol.

Form Supplied in: very hygroscopic solid; commercially avail-able; purity ≈80%; the remainder is 1,2-dichloroethane. Theprecursors Ph3P and Cl2 are both widely available. Ph3P: odor-less platelets or prisms; purity ≈99%; typical impurity is Ph3PO≈1%. Cl2: greenish-yellow gas, with suffocating odor; purity>99.3%; typical impurities are Br2, C2Cl6, C6Cl6, and H2O.

Analysis of Reagent Purity: adduct:2,3 31P NMR (various sol-vents and solid state) +47 to +66 (ionic form), −6.5 to +8(covalent form); Raman (solid state) ν(P–Cl) 593 cm−1 (ionicform), 274 cm−1 (covalent form). Typical impurities, Ph3P andPh3PO: 31P NMR (various solvents) −5 to −9 and +25 to+42, respectively.

Preparative Methods: various preparations have been described;5

the adduct is usually prepared just before use by addition of astoichiometric amount of Chlorine to Triphenylphosphine ina dry solvent.2

Handling, Storage, and Precautions: adduct: exceedingly sensi-tive to moisture; incompatible with strong oxidizing agents andstrong bases; may decompose on exposure to moist air or wa-ter; do not get in eyes, on skin, or on clothing; keep containersclosed and store in a cool dry place; these reagents should behandled in a fume hood.

Alkyl Chlorides from Alcohols and Ethers. The reaction ofPh3PCl2 with alcohols provides an excellent synthetic method forthe preparation of alkyl chlorides.6 Mechanistic studies6c suggestthe rapid initial formation of an alkyloxyphosphonium intermedi-ate which then undergoes slow conversion into Ph3PO and alkylchloride (eq 1).6b,c It is assumed that chlorination takes place byan SN2 reaction in most cases; thus, inversion of configuration isobserved in the transformation of (−)-menthol to (+)-neomenthyl

chloride (eq 2).6a As illustrated in eq 1, primary,6b,7 secondary,6

and even tertiary6b alcohols are chlorinated with Ph3PCl2, al-though reactions of tertiary alcohols are often accompanied byelimination (10%).

(1)ROPPh3 Cl–+ SN2

OPPh3 + RCl

90–99%

R = Bu, neopentyl, Cy, t-Bu; DMF, reflux

ROHPh3PCl2

fast slow

(2)OH ClPhH, reflux

93%

Ph3PCl2

‘Ph3PCl2’, generated in situ from Ph3P and Hexachloroace-tone (HCA) has proven to be a very efficient reagent for the regio-and stereoselective chlorination of allylic alcohols (eq 3),8 and forthe regioselective conversion of sterically hindered cyclopropyl-carbinyl alcohols into cyclopropylcarbinyl chlorides (eq 4).9 Chlo-rination of allylic alcohols occurs in less than 20 min, with totalpreservation of the double bond geometry and with >99% inver-sion of configuration for optically active alcohols. Primary andsecondary alcohols give predominantly the unrearranged chlo-rides, while tertiary alcohols provide mostly rearranged prod-ucts, with elimination to dienes becoming an important sidereaction with more highly substituted systems. Similarly, cyclo-propylcarbinyl alcohols yield the corresponding chlorides with notrace of homoallylic chlorides or cyclobutane derivatives.

R2

R1 R3

HOR4 R2

R1 R3

ClR4

(3)+ γ-isomer

R1, R2, R3, R4 = H, Me α:γ = 100:0 to 82:18α-isomer

HCA, 0 °C then rt90–100%

Ph3PCl2

(4)R

OH

Cl

R

R = H, Me, Et, Pr, Bu, i-Pr, t-Bu

HCA, 20 °C79–93%

Ph3PCl2

In the carbohydrate field, primary and secondary alco-hols are chlorinated in excellent yield (80–95%) with thePh3PCl2/ImH (Imidazole) reagent system in PhMe, MeCN, ora MeCN/pyridine mixture at rt to reflux temperature.10 Polymer-supported Ph3PCl2,11 prepared by the Ph3PO/COCl2 (Phosgene)procedure,5b has been used to transform PhCH2OH to PhCH2Cl(88%) in MeCN as a solvent; the simple workup consists of filtra-tion of polymeric phosphine oxide and solvent removal. Severalexamples have been reported of the direct conversion of ethersinto chlorides, as in eq 57 Enol ethers such as acetophenonetrimethylsilyl ether give α-chlorostyrene (30%) by Ph3PCl2 treat-ment at CCl4 reflux.12

Avoid Skin Contact with All Reagents

2 TRIPHENYLPHOSPHINE DICHLORIDE

(5)

O CH2Cl

CH2ClCCl4, reflux91%

Ph3PCl2

Aryl Chlorides from Phenols and Arenes. Heating phenolswith Ph3PCl2 at 120–140 ◦C leads to the corresponding aryl chlo-rides in good yield (eq 6).13 A related chlorination reaction em-ploys the Ph3PCl2/BSPO (Bis(trimethylsilyl) Peroxide) reagentsystem as the electrophilic chlorine source. With this reagent,in MeCN at rt, aromatic hydrocarbons bearing electron-donatingsubstituents, such as 2,4,6-tri-t-butylbenzene and mesitylene, af-ford 1-monochloroarenes, while anisole gives a mixture of 2- and4-chloro derivatives, in moderate to good yields (44–86%).14a

Similar aromatic para chlorination has also been observed by heat-ing anisole with Ph3P+Cl PCl5−, albeit in low yield (33%).14b

R3

R2

R1

OH

R3

R2

R1

Cl

(6)

R1 = H, NO2, Me; R2 = H; R3 = H, Me, NO2, PhR1 + R2, R2 + R3 = Ph

Ph3PCl2CCl4 then neat

120–140 °C57–79%

Vinyl Chlorides, Alkynyl Ketones, and βββ-Chloro-ααα-vinylKetones from Ketones andβββ-Diketones. 1-Chlorocyclohexene(45%) and α,α-dichlorotoluene (59%) are produced bythe reaction of cyclohexanone and benzaldehyde withPh3PCl2/Triethylamine and Ph3PCl2 alone, respectively, inrefluxing PhH.6a In MeCN as solvent, polymer-supportedPh3PCl2 converts acetophenone into α-chlorostyrene (75%).11

In a similar fashion, unsymmetrical fluorinated β-diketonesgive 3:1 mixtures of α,β-ynones (eq 7) in good overall yields(slightly lower than those obtained with TriphenylphosphineDibromide).15a β-Chloro-α,β-unsaturated ketones are preparedin high yield from cyclic β-diketones (eq 8).15b,c

Ph R

O O

R

O

Ph

Ph

O

R

CH2Cl2, rt84–85%

+

3:1

(7)

R = CF3, C3F7

Ph3PCl2, Et3N

(8)

O

R1

OR2

R3

O

R1

ClR2

R3

PhH, CCl4, rt90–97%( )n ( )n

R1, R2, R3 = H, Me; n = 0, 1

Ph3PCl2, Et3N

Epoxide Cleavage to Vicinal Dichlorides and Chlorohy-drins. Early reports of work in this area described the ringopening of ethylene oxide with Ph3PCl2 in CCl4 at rt, leadingto 1,2-dichloroethane.16a Subsequently,16b,c excellent yields werereported in the reaction of Ph3PCl2 with aliphatic epoxides to pro-duce the corresponding vicinal dichlorides. The ring opening takesplace stereospecifically with both cis and trans epoxides in PhHor CH2Cl2 at reflux, in each case providing the dichloride derived

from SN2 displacement on each C–O bond (eq 9).16c Alkoxyphos-phonium chloride intermediates have even been isolated and char-acterized in a study involving ethylene oxide derivatives.16d

O

Cl

Cl

OPPh3

Cl(9)

Cl–

PhH, 0 °C then reflux71–73%

+

Ph3PCl2

The reaction of epoxides with Ph3PCl2 in anhydrous CH2Cl2 atrt17a results in chlorohydrins in generally high yields (90–96%).With conformationally rigid epoxides the oxirane ring cleavageappears to be quite stereoselective, leading only to the prod-ucts resulting from the usual anti opening of the ring. Less hin-dered and rigid cyclic substrates provide regioisomeric mixtures ofcyclic trans-chlorohydrins. The reaction of the polymer-supportedPh3PCl2 reagent proceeds in a similar fashion with even higheryields and easier workup; simple filtration and evaporation pro-vides the product (eq 10).17b

(10)

O

R1 R2

HR3

PPh2Cl2R1

R2

R3

OH

H

Cl

CH2Cl2, rt96–98%

Acid Chlorides from Acids and Esters. Mono- and dicar-boxylic acids give acyl chlorides on reaction with Ph3PCl26a

or polymer-supported Ph3PCl211 in PhH, CH2Cl2, or MeCN(eq 11).11 On similar Ph3PCl2 treatment in PhH at −10 ◦C tort, sulfamic acid (H2NSO3H) is transformed into Ph3P=NSO2Clin 95% yield.18 Analogously, Ph3PCl2, generated in situfrom Ph3P and (EtO)2P(=O)SCl, reacts with Et3N and(EtO)2P(O)SH at −78 ◦C to provide the corresponding acidchloride (EtO)2P(S)Cl.19

(11)R(CO2H)nCH2Cl2 or MeCN, rt or reflux

87–100%

R(COCl)n

R = PhCH2, 4-MeC6H4 (n = 1); 1,4-C6H4, 1,3-C6H4 (n = 2)

polymer-C6H4PPh2Cl2

Direct cleavage of esters or lactones.20 to both acid and alkylchlorides is achieved with Ph3PCl2; halogenated esters (RCO2Me;R = CF3, CCl3, CH2Cl) are readily cleaved in refluxing MeCN,while esters of nonhalogenated acids and lactones (eq 12) requirehigher temperatures or/and the use of additives such as Boron Tri-fluoride Cleavage is considerably retarded by steric hindrance inthe alkoxy fragment. A mechanism involving initial nucleophiliccleavage of the O–alkyl bond with Cl− is proposed for halogenatedesters, whereas an initial electrophilic attack by Ph3P+Cl on thecarbonyl oxygen is assumed for the cleavage of nonhalogenatedesters.

O

O

Cl

O

Cl(12)

Ph3PCl2neat, 180 °C

97%

Similar transformations of esters to acid chlorides have alsobeen achieved in the phosphonate diester field21 and in the con-version of trialkyl phosphites into dialkyl chlorophosphites.22

A list of General Abbreviations appears on the front Endpapers

TRIPHENYLPHOSPHINE DICHLORIDE 3

Ph3PCl2 acts as a mild reagent for the replacement of a singleester linkage by a chloride in phosphonate diesters (eq 13).

P

O

ROMe

OMeP

O

RCl

OMe(13)

R = Me, Pr, allyl, MeOCO, i-PrOCO, PhOCO

Ph3PCl2CHCl3, rt

73–97%

Chlorination and Dehydration of Substituted CarboxamideGroups. Secondary amides and N,N,N′-trisubstituted ureas pos-sessing an N–H bond are converted to imidoyl chlorides11,23 andchloroformamidines,5a, respectively, by reaction with Ph3PCl2(eqs 14 and 15). Unsupported or polymer-supported reagent hasbeen used, with or without Et3N, in a variety of solvents. Undervery similar conditions, with Ph3PCl2 in CH2Cl2 at reflux, the pri-mary amide PhCONH2 is dehydrated to the nitrile PhCN (78%),11

while aryl-substituted arylhydroxamic acids are dehydrated to thecorresponding aryl isocyanates.25 In the latter case, dehydrationoccurs via Lossen-type rearrangement of a phosphorane interme-diate. In a related reaction, chlorination–dehydrochlorination ofN-acylated hydrazines with the Ph3PCl2/Et3N system is a smoothone-pot procedure to generate nitrilimines.26 Thus, by such treat-ment, PhCONHNHPh affords [PhC≡N+–N+–Ph] in situ; thisreacts with alkenic or alkynic dipolarophiles to give pyrazolinesand pyrazoles.

(14)R1CONHR2

Ph3PCl2, Et3N orpolymeric reagent

R1C(Cl)=NR2

R1 = Ph, Me; R2 = Ph, Cy

MeCN, rt or reflux35–93%

(15)

Ph3PCl2, Et3NMeCN or PhH

R1NHCONR2R3 R1N=C(Cl)NR2R3

R1 = Et, Pr, Ph; R2 = Et, Bu, Ph; R3 = Me, Et, Bu

rt or reflux61–75%

Iminophosphoranes from Amines, Hydrazines, and RelatedDerivatives. Iminophosphoranes (or phosphinimines) are com-monly used as intermediates, especially in heterocyclic synthe-sis. Phosphinimines can be obtained via phosphorylation of pri-mary amines with Ph3PCl2 alone,27 or in the presence of Et3N,28

if necessary, to ensure the last dehydrochlorination step. In theheterocyclic β-enamino ester field, iminophosphoranes are sub-mitted to vinylogous alkylation28a or cycloaddition (eq 16)28a,b

with ring enlargement. The =PPh3 moiety, which serves as atemporary amino protecting group, is then cleaved hydrolyti-cally. Reaction of phosphinimines with aryl isocyanates affordscarbodiimides,28c whereas iminophosphoranes of acyl hydrazinesundergo dimerization to tetrazines.28d Other phosphinimines andphosphonium salts have been prepared from phosphorylationof amino derivatives, such as hydrazines,29a urethanes,29b andN-silylated imines,29c with Ph3PCl2.

N

CO2Me

NH2

Ts

N

CO2Me

N

Ts

PPh3

N

MeO2C

CO2Me

NH2

(16)

Ph3PCl2, Et3N 1. HC≡CCO2Me

Ts

85%

MeCN, rt then reflux85%

2. H+, EtOH

Other Applications. Ph3PCl2 is a good condensation reagentfor the synthesis of ketones (48–90%) from carboxylic acids andGrignard reagents. The versatility of the method is illustrated bythe chemoselective reaction of carboxylic acids possessing suchfunctional groups as halogen, cyano, and carbonyl (eq 17).30

CO2Li (17)

O

Ph( )4 2. Ph(CH2)2MgBr THF, –30 °C

( )2Et

O

( )4Et

O

72%

1. Ph3PCl2

Beckmann rearrangement of benzophenone oxime toPhC(Cl)=NPh (82%) is promoted by Ph3PCl2/Et3N inCH2Cl2 at rt.31a Cyclopentanone and cyclohexanone oximeare converted to δ-valero- and ε-caprolactam (76 and 86%)with Ph3PCl2 in PhH at 50–60 ◦C.31b The action of heat(120–130 ◦C) on a mixture of Ph3PCl2 with the highly fluori-nated propanol (CF3)2C(OH)CH2SO2CF3 leads to eliminationof the CF3SO2 group and formation of the vinylic chloride(CF3)2C=CHCl.32 Ph3PCl2 reacts with Pb(SCN)2 to formPh3P+–N=C=S SCN−, another reagent of the pseudohalophos-phonium type, which is used for converting hydroxy groupsinto thiocyanate and isothiocyanate functions.33 Ylides such astriphenylphosphonio(vinylsulfonylphenylsulfonylmethanide),CH2=CHSO2C+–(P+Ph3)SO2Ph, can be prepared by reac-tion of Ph3PCl2 with the very activated methylene derivativeCH2=CHSO2CH2SO2Ph.34 Heating Ph3PCl2 with (Me3Si)2Sat 60–70 ◦C leads to the formation of Ph3PS (85%) afterdistillation of the Me3SiCl byproduct.35 Ph3PCl2 is reduced toPh3P with formation of alkyl or aryl chlorides by reaction withorganometallic reagents (Mg, Li).36

1. Castro, B. R., Org. React. 1983, 29, 1.

2. The Ph3PCl2 adduct can be prepared by different routes; the mostcommon involves the reaction of Ph3P and Cl2, both being generallyused in solution, in order to ensure a correct 1/1 stoichiometry. Asillustrated by physical studies,3 the resultant product is often a mixture ofseveral compounds depending on starting materials (Ph3P, Ph3PO, Cl2,COCl2, CCl3CCl3, CCl3COCCl3), on their stoichiometries, and on thepolarity of the solvent used for the preparation. 31P NMR studies undervarious conditions, and solid state Raman measurements, lead to differentvalues for ionic PIV and molecular PV species or to average valuescorresponding to equilibrated mixtures of the both structures accordingto the polarity of the solvent.

3. (a) Al-Juboori, M. A. H. A.; Gates, P. N.; Muir, A. S., J. Chem. Soc.,Chem. Commun. 1991, 1270. (b) Dillon, K. B.; Lynch, R. J.; Reeve, R.N.; Waddington, T. C., J. Chem. Soc., Dalton Trans. 1976, 1243, andliterature cited therein.

Avoid Skin Contact with All Reagents

4 TRIPHENYLPHOSPHINE DICHLORIDE

4. Another preparation from Ph3P and CCl3CCl3 in MeCN providesmaterial of higher mp: 207–210 ◦C (from MeCN–petroleum ether); seeAppel, R.; Schöler, H., Chem. Ber. 1977, 110, 2382.

5. Apart from the classical Ph3P + Cl2 method, the following routes havebeen reported: (a) Ph3P + COCl2: Appel, R.; Ziehn, K. D.; Warning,K., Chem. Ber. 1973, 106, 2093, and literature cited therein. (b)Ph3PO +COCl2: Masaki, M.; Kakeya, N., Angew. Chem., Int. Ed. Engl. 1977,16, 552, and literature cited therein. (c)Ph3P + CCl4 in the presenceof RNHCOCl: Appel, R.; Warning, K.; Ziehn, K. D.; Gilak, A., Chem.Ber. 1974, 107, 2671. (d) With Ph3P + CCl4 alone, a mixture of equalamounts of Ph3PCl2 and Ph3P=CCl2 is obtained: Rabinowitz, R.;Marcus, R., J. Am. Chem. Soc. 1962, 84, 1312; Appel, R.; Knoll, F.;Michel, W.; Morbach, W.; Wihler, H.-D.; Veltmann, H., Chem. Ber. 1976,109, 58. (e) Ph3P + CCl3CCl3, e. g. Ref. 4 and: Appel, R.; Halstenberg,M. In Organophosphorus Reagent in Organic Synthesis, Cadogan, J.I. G., Ed.; Academic: New York, 1979; Chapter 9 and literature citedtherein. (f) Ph3P + CCl3COCCl3 for in situ preparation of Ph3PCl2: seeRef. 8 and 9 (g)Ph3PO or Ph3P + PCl5: Dillon, K. B.; Reeve, R. N.;Waddington, T. C., J. Inorg. Nucl. Chem. 1976, 38, 1439, and literaturecited therein.

6. (a) Horner, L.; Oediger, H.; Hoffmann, H., Justus Liebigs Ann. Chem.1959, 626, 26. (b) Wiley, G. A.; Hershkowitz, R. L.; Rein, B. M.; Chung,B. C., J. Am. Chem. Soc. 1964, 86, 964. (c) Wiley, G. A.; Rein, B. M.;Hershkowitz, R. L., Tetrahedron Lett. 1964, 2509.

7. Skvarchenko, V. R.; Lapteva, V. L.; Gorbunova, M. A., J. Org. Chem.USSR (Engl. Transl.) 1990, 26, 2244.

8. (a) Magid, R. M.; Fruchey, O. S.; Johnson, W. L., Tetrahedron Lett. 1977,2999. (b) Magid, R. M.; Fruchey, O. S.; Johnson, W. L.; Allen, T. G., J.Org. Chem. 1979, 44, 359.

9. (a) Hrubiec, R. T.; Smith, M. B., Synth. Commun. 1983, 13, 593.(b) Hrubiec, R. T.; Smith, M. B., J. Org. Chem. 1984, 49, 431.

10. (a) Garegg, P. J.; Johansson, R.; Samuelsson, B., Synthesis 1984, 168.(b) Garegg, P. J., Pure Appl. Chem. 1984, 56, 845.

11. Relles, H. M.; Schluenz, R. W., J. Am. Chem. Soc. 1974, 96, 6469.

12. Lazukina, L. A.; Kolodyazhnyi, O. I.; Pesotskaya, G. V.; Kukhar’, V. P.,J. Gen. Chem. USSR (Engl. Transl.) 1976, 46, 1931.

13. Hoffmann, H.; Horner, L.; Wippel, H. G.; Michael, D., Chem. Ber. 1962,95, 523.

14. (a) Shibata, K.; Itoh, Y.; Tokitoh, N.; Okazaki, R.; Inamoto, N., Bull.Chem. Soc. Jpn. 1991, 64, 3749. (b) Timokhin, B. V.; Dudnikova, V. N.;Kron, V. A.; Glukhikh, V. I., J. Org. Chem. USSR (Engl. Transl.) 1979,15, 337.

15. (a) Chechulin, P. I.; Filyakova, V. I.; Pashkevich, K. I., Bull. Acad.Sci. USSR, Div. Chem. Sci. 1989, 38, 189. (b) Piers, E.; Nagakura, I.,Synth. Commun. 1975, 5, 193. (c) Piers, E.; Grierson, J. R.; Lau, C. K.;Nagakura, I., Can. J. Chem. 1982, 60, 210.

16. (a) Gloede, J.; Keitel, I.; Gross, H., J. Prakt. Chem. 1976, 318, 607. (b)Sonnet, P. E.; Oliver, J. E., J. Org. Chem. 1976, 41, 3279. (c) Oliver, J.E.; Sonnet, P. E., Org. Synth. 1978, 58, 64. (d) Appel, R.; Gläsel, V. I.,Z. Naturforsch., Till B 1981, 36, 447.

17. (a) Palumbo, G.; Ferreri, C.; Caputo, R., Tetrahedron Lett. 1983, 24,1307. (b) Caputo, R.; Ferreri, C.; Noviello, S.; Palumbo, G., Synthesis1986, 499.

18. Arrington, D. E.; Norman, A. D., Inorg. Synth. 1992, 29, 27.

19. Krawczyk, E.; Mikolajczak, J.; Skowronska, A.; Michalski, J., J. Org.Chem. 1992, 57, 4963.

20. (a) Burton, D. J.; Koppes, W. M., J. Chem. Soc., Chem. Commun.1973, 425. (b) Burton, D. J.; Koppes, W. M., J. Org. Chem. 1975, 40,3026.

21. Ylagan, L.; Benjamin, A.; Gupta, A.; Engel, R., Synth. Commun. 1988,18, 285.

22. Gazizov, M. B.; Zakharov, V. M.; Khairullin, R. A.; Moskva, V. V., J.Gen. Chem. USSR (Engl. Transl.) 1986, 56, 1471.

23. Appel, R.; Warning, K.; Ziehn, K.-D., Chem. Ber. 1973, 106, 3450.

24. Appel, R.; Warning, K.; Ziehn, K.-D., Chem. Ber. 1974, 107, 698.

25. von Hinrichs, E.; Ugi, I., J. Chem. Res. (S) 1978, 338; J. Chem. Res. (M)1978, 3973.

26. Wamhoff, H.; Zahran, M., Synthesis 1987, 876.

27. (a) Roesky, H. W.; Giere, H. H., Chem. Ber. 1969, 102, 2330.(b) Gotsmann, G.; Schwarzmann, M., Justus Liebigs Ann. Chem. 1969,729, 106.

28. (a) Wamhoff, H.; Haffmanns, G.; Schmidt, H., Chem. Ber. 1983, 116,1691. (b) Wamhoff, H.; Hendrikx, G., Chem. Ber. 1985, 118, 863.(c) Wamhoff, H.; Haffmanns, G., Chem. Ber. 1984, 117, 585. (d) Farkas,L.; Keuler, J.; Wamhoff, H., Chem. Ber. 1980, 113, 2566.

29. (a) Zhmurova, I. N.; Yurchenko, V. G.; Pinchuk, A. M., J. Gen. Chem.USSR (Engl. Transl.) 1983, 53, 1360. (b) Shevchenko, V. I.; Shtepanek,A. S.; Kirsanov, A. V., J. Gen. Chem. USSR (Engl. Transl.) 1962, 32,2557. (c) Lazukina, L. A.; Kristhal’, V. S.; Sinitsa, A. D.; Kukhar’, V. P.,J. Gen. Chem. USSR (Engl. Transl.) 1980, 50, 1761.

30. Fujisawa, T.; Iida, S.; Uehara, H.; Sato, T., Chem. Lett. 1983, 1267.

31. (a) Appel, R.; Warning, K., Chem. Ber. 1975, 108, 1437. (b) Sakai, I.;Kawabe, N.; Ohno, M., Bull. Chem. Soc. Jpn. 1979, 52, 3381.

32. Samusenko, Y. V.; Aleksandrov, A. M.; Yagupol’skii, L. M., J. Org.Chem. USSR (Engl. Transl.) 1975, 11, 622.

33. Burski, J.; Kieszkowski, J.; Michalski, J.; Pakulski, M.; Skowronska, A.,J. Chem. Soc., Chem. Commun. 1978, 940.

34. Diefenbach, H.; Ringsdorf, H.; Wilhelms, R. E., Chem. Ber. 1970, 103,183.

35. Markovskii, L. N.; Dubinina, T. N.; Levchenko, E. S.; Kukhar’, V.P.; Kirsanov, A. V., J. Org. Chem. USSR (Engl. Transl.) 1972, 8,1869.

36. (a) Denney, D. B.; Gross, F. J., J. Org. Chem. 1967, 32, 3710. (b) Dmitriev,V. I.; Timokhin, B. V.; Kalabina, A. V., J. Gen. Chem. USSR (Engl.Transl.) 1979, 49, 1936.

Jean-Robert Dormoy & Bertrand CastroSANOFI Chimie, Gentilly, France

A list of General Abbreviations appears on the front Endpapers