A new, powerful glycosylation method: activation of thioglycosides with dimethyl disulfide-triflic anhydride.

Dimethyl disulfide reacts with triflic anhydride to provide a highly reactive electrophile. Various thioglycosides, differing in their thio aglycons, carbohydrate units, and protecting group pattern, were activated with Me2S2-Tf2O in the presence of different glycosyl acceptors. The reactions proceeded at low temperatures within a short time, affording oligosaccharides in high yields both on primary and secondary hydroxyls. Armed and disarmed glycosyl donors were activated equally efficiently.