Phosphinothioic amides

In addition to the sulfoximines, Johnson has studied phosphinothioic amides as alkene precursors. This reagent has not achieved the popularity of the sulfoximines. It can be utilized for ketone methylen-ation with resolution, as well as for Ae synthesis of more highly substituted alkenes. Rigby has found that in the synthesis of guaianolides this reagent was effective where Peterson and Wittig reactions gave only p-elimination. ... 

The reaction between the thiophosphorus(III) amide 21 and benzyl bromide is of interest in that it is possible to isolate a pseudoquatemary salt 22, which decomposes at just above its melting point (92-93 °C) to give the corresponding phosphinothioic amide (23). ... 

Phosphinothioic amides are highly effective reagents for the alkylidenation of ketones, and the method has been developed as a means of methylenation coupled with optical resolution. The reaction of the anion of the phosphinothioic amide (21) gives the diastereoisomeric mixture (22), which, after separation, can be converted into the optically active olefins (23). The method has been applied to the synthesis of the (+)- and ( —)-iridoid monoterpene hop ether (24), and can be extended to alkylidenation with resolution. 

The asymmetric olefination of the racemic ketone 111 with the anion of the phosphinothioic amide 15 can be regarded as an example of kinetic resolution ... 

A variety of compounds have been examined which are in the phosphinic acid class. They include a phenyl cyclopentyl ester,184 a phosphinothioic anhydride,185 a dipheny1phosphinamide, 86 a red bis(di-t-buty1thiophosphinamide) and its selenide analogue,187 the anisylphosphor inane (67),1 88 the thioamide (68),1 89 and the phospholenium amide (69, Y = i-Pr2N).190... 

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