Facile triflic acid-catalyzed α-1,2-<i>cis</i>-thio glycosylations: scope and application to the synthesis of<i>S</i>-linked oligosaccharides, glycolipids, sublancin glycopeptides, and T_N/T_Fantigens

Abstract

Studies of <i>S</i>-linked glycoconjugates have attracted growing interest because of their enhanced chemical stability and enzymatic resistance over <i>O</i>-glycoside counterparts. We here report a facile approach to access α-1,2-<i>cis-S</i>-linked glycosides using triflic acid as a catalyst to promote the glycosylation of a series of thiols with d-glucosamine, galactosamine, glucose, and galactose electrophiles. This method is broadly applicable for the stereoselective synthesis of <i>S</i>-linked glycopeptides, oligosaccharides and glycolipids in high yield and excellent α-selectivity. Many of the synthetic limitations associated with the preparation of these <i>S</i>-linked products are overcome by this catalytic method.