Alkenylphosphonates Alkenylphosphonic diesters, phosphonates

Pyrolysis (in boiling toluene) of the sulphoxide obtained from a dialkyl (l-phenylth> ioalkyl)phosphonate (339) and 3-chloroperoxybenzoic acid affords an alkenephosphonic diester, and subsequent work showed that the sequence was adaptable to the production of chiral esters of alkenylphosphonic diester with optical purities of not less than 93%. Use of the ( S )p-phosphonic amide 340 afforded a mixture of the (E)-(S)p- and (Z)-(S)p-stereoisomers (341), separable by chromatographic methods. ... 

The use of esters of a (substituted-methyl)phosphonic acid to provide the carbanion site next to phosphoryl phosphorus was a natural step forward. The most successful development has been the use of the carbanion 346 derived from esters of methylenebisphospho-nic acid (or its monoalkylated derivatives). The anion 346 reacts with an aldehyde to afford the alkenylphosphonic diester 347 (R = Et, Ph, PhCH—CH, 2-thienyl, 2-pyridinyl, etc,) ". Use of the protected 3-pyridinylcarboxaldehyde 348 allowed the preparation of the ester 349, which, after reduction of the C=C bond and hydrolysis, afforded the phosphonic acid 350 Such reactions have also been carried out under phase-transfer condi-tions. Reactions between the lithium salt of the ester 351 and benzaldehyde or but-2-enal give the (alk-1 -enyl)phosphonic esters 352 and 353 in the ratio 1 4 the lithium salts 354 and 355 are formed concomitantly in the ratio 4 1. ... 

Scheme 11 indicates the usefulness of salts derived from Wittig ylide reagents and anhydrides of perfluorocarboxylic acids in the synthesis of fluorinated alkenylphosphonic diesters (127), often together with (epoxyalkyl)phosphonic diesters (128)(Rf = CF3 or... 

The addition of a nitroalkane to an alkenylphosphonic diester is exemplified by the interaction of nitromethane with diethyl ethenylphosphonate in the presence of NaOEt, when the product is diethyl (3-nitropropyl)phosphonate and by a similar addition to 1,1-bis(diethoxyphosphinoyl)ethane . In the initial stages of a synthesis of (4,5,6-trihydroxy-3-oxohexyl)phosphonic acid, the nitro sugar 76 was made to add to dibenzyl ethenylphosphonate, but the resultant (3-nitropropyl)phosphonic dibenzyl ester 77 was then used without isolation. ... 

Alkene-,alkyne-,aryl-phosphonic and phosphinic acids.-(of-Stannylalkyl)phosphonic acid diesters have been employed to prepare alkenylphosphonic diesters. Treatment of the tin compounds (251) (generated in situ) with an aldehyde R CHO at -70 yielded a mixture of ( ) and (Z) isomers of (252), the proportions being controlled essentially by... 

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