Phosphinoselenoic amides

This method was also used for the preparation of P-chiral phosphinoselenoic amides (Rp,5)-61 and (Sp,S)-62 (Scheme 19). Enantiomerically pure amides 61,62 were synthesized by reaction of racemic phosphinoselenoic chlorides rac-60 with opticaUy-active lithium amides. Two diastereomers of (Rp,S)-61 and (Sp,S)-62 were formed in a nearly equal ratio in high yields, and the two diastereomers were successfully separated by column chromatography on silica gel. The absolute configuration of phosphinoselenoic amide (/ p,S )-61 was determined by X-ray analysis. Using this reaction, enantiomerically pure salts of phosphinoselenoic acid 63 and P-chiral phosphinoselenoic chlorides ( )-(5)-60 were prepared (Scheme 20) [45, 46]. 

Kimura T, Murai T (2004) P-Chiral phosphinoselenoic chlorides and optically active P-chiral phosphinoselenoic amides synthesis and stereospecific interconversion with extrusion and addition reactions of the selenium atom. Chem Lett 33 878-879... 

Series of selenium-containing phosphorus compounds (137-139) have been reported by Kimura and Murai. Phosphinoselenoic amides 137 were prepared from racemic phosphinoselenoic chlorides (138) and chiral amines and the individual isomers could be separated by column chromatography in some cases.Reaction of 137 with tributylphosphine afforded the P(III) aminophosphines with retention of configuration at the phosphorus atom. (5)-methylbenzylamine was also used to prepare both enantiomers of phosphinoselenoic chlorides 138 in 96% ee. In contrast to the oxygen analogues, they were found to be stable and could be purified by column chromatography. Several compounds, such as 139 for example, were prepared by stereoselective nucleophilic substitutions of the Cl atom. ... 

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