Cyclic Sulfur Ylides Derived from Gleason-Type Chiral Auxiliaries for the Asymmetric Synthesis of Epoxy Amides

Abstract

Gleason-type chiral auxiliaries were used for the synthesis of a novel class of sulfonium salts, obtained via methylation of the sulfide with Meerwein's salt. The salts were reacted with aldehydes under basic conditions to provide epoxy amides, which were reduced to their corresponding epoxy alcohols in excellent enantiomeric excesses. Interestingly, it was feasible to synthesize both enantiomeric epoxy alcohols depending on which of the sulfonium salts, prepared from L-amino acids (6 and 9 from L-valine or 15 and 16 from L-serine) was employed.