Acylation of 2,4-Disubstituted Thiazolidines and Oxazolidines. Concomitant Epimerization at C-2

Abstract

Abstract Acylation of diastereomers of 2,4-disubstituted 4(R)-alkoxycarbonyl thiazolidines and oxazolidines with acyl chlorides affords (2R,4R)-3-acyl isomer as only product without any racemization. The reaction proceeds via concomitant epimeriaztion at C-2 of (2S,4R) diastereomer of the substrates.