A Facile and Direct Glycosidation Method for the Synthesis of 2‐Deoxy α‐Rhamnosides Catalyzed by Ferric Chloride

A facile and highly efficient O‐glycosylation method for stereoselective synthesis of 2,6‐dideoxy‐O‐glycosides has been described promoted by FeCl3, an eco‐friendly, easily available and non‐toxic catalyst. Acetylated 2‐deoxy rhamnoside was chosen as the glycosyl donor for its convenient preparation and great stability at room temperature. The glycosylation was amenable to a wide range of acceptors including primary, secondary, tertiary alcohols, sterols, amino acid derivatives and sugar derivatives. Thus, 2,6‐dideoxyglycosides and oligosaccharides were obtained in short reaction time (19:1). An efficient O‐glycosylation method for stereoselective synthesis of 2,6‐dideoxy glycosides catalyzed by iron(III). The conveniently prepared and bench‐stable 2,6‐dideoxy glycoside donor can react with a series of alcohol acceptorsto obtain corresponding 2,6‐dideoxyglycosides and oligosaccharidesin good to excellent yields with preponderant α‐selectivity.