ASYMMETRIC-SYNTHESIS OF CHIRAL ORGANOSULFUR COMPOUNDS USING N-SULFINYLOXAZOLIDINONES

This paper describes a new class of chiral sulfinyl transfer reagents, 4 and 5 (R = aryl, alkyl), which are readily prepared from the oxazolidinones derived from (4R,5S)-norephedrine (HX(N)) and (4S)-phenylalanine (HX(p)), respectively. [graphics] These N-sulfinyloxazolidinone reagents can be synthesized either by sulfinylation of the metalated oxazolidinones or by oxidation of the derived N-sulfenimides to afford the diastereomeric N-sulfinyloxazolidinones which may be readily purified by chromatography. These sulfinylating agents react with a wide range of nucleophiles such as Grignard reagents, enolates, lithium alkoxides, or metalated amides, with inversion of configuration at the sulfur center to afford the derived chiral sulfoxides, sulfinate esters, and sulfinamides in high yields and enantioselectivities. Competition experiments have established that this family of chiral sulfinylating agents is at least 100 times as reactive as the corresponding menthyl sulfinate esters toward Grignard reagents.