Sulfuric acid immobilized on silica: an efficient promoter for one-pot acetalation–acetylation of sugar derivatives

Sulfuric acid immobilized on silica gel has been used as an efficient and safe alternative promoter for acetalation and subsequent acetylation of sugar glycosides using stoichiometric reagents without work-up. The synthesis of different types of per-O-acetylated acetals/ketals has been achieved from various types of O- and S-glycosides in excellent yields.