The synthesis of chiral organosul fur and phosphorus compounds /

Abstract

A general route to optically active organosulfur and phosphorus compounds was investigated. Sulfinimides incorporating camphorimide were synthesized directly from a sulfinyl chloride and N-(trimethylsilyl)camphorimide. The diastereomers were found to be inseparable by crystallization or chromatography, although in one case an optically active sulfinamide was prepared by an asymmetric synthesis.The phosphorus-imide bond was formed by coupling of an asymmetric phosphinous chloride and N-(trimethylsilyl)camphorimide. Addition of sulfur gave N-(phosphinothioyl)camphorimides as separable diastereomers. These were converted into optically active thiophosphoryl compounds which were chiral only at phosphorus. The absolute configurations of the diastereomers were obtained by single-crystal X-ray analysis, through NMR techniques and by conversion into phosphinothioic acids.Displacement of camphorimide was effected with organometallic reagents, alcohols and thiols to give optically active phosphine sulfides, phosphinothionates and phosphinodithioates respectively. Optical yields of the products were dependant on the reagents and reaction conditions used. Mechanistic rationales are presented to account for the stereochemical results