Nucleophilic Addition Reactions on Glycosyl 1,2-Orthoesters

Abstract

1,2-trans glycosides can be synthesized in a stereoselective manner through glycosyl 1,2-orthoesters. The utility of the protocol was demonstrated by the stereoselective synthesis of various carbohydrate epitopes present in infectious bacteria exploiting salient features of gold(III) catalysis. 1,2-orthoesters are stable and can be stored for longer periods without any degradation or decomposition. We envisioned that 1,2-orthoesters are highly useful synthons for the synthesis of those azido glycosides and cyano compounds where the C-2 hydroxyl group needs to become free for further chemistry. In this study, we explored utility of gold (III) catalysis for opening of propargyl 1,2-orthoesters by N- and C- nucleophiles.