Stereoselective reaction of methyl α- and β-D-glycopyranosides with acetic anhydride in the presence of trimethylsilyl trifluoromethanesulphonate

Abstract

Treatment of methyl β-D-glycopyranosides with TMSOtf–Ac₂O gives acyclic products by selective cleavage of the ring carbon–oxygen bond, whereas methyl α-D-isomers undergo replacement of the anomeric methoxy by an acetoxy group with retention of configuration.