Ferric Chloride Promoted Glycosidation of Alkyl Thioglycosides.

Reported herein is a new reaction for glycosylation with thioglycosides in the presence of iron(III) chloride. Previously, FeCl was used for the activation of thioglycosides as a Lewis acid co-promoter paired with NIS. In the reported process, although 5.0 equiv of FeCl are needed to activate thioglycosides most efficiently, no additives were used, and the reactions with reactive glycosyl donors smoothly proceeded to completion in 1 h at 0 °C. This work showcases a new direction in developing glycosylation methods using greener and earth-abundant activators.