Efficient activation of armed glycosyl trichloroacetimidates with Sm(OTf)3 in the stereoselective glycosidation of saccharidic acceptors

Catalytic amounts of Sm(OTf)3 activate armed glycosyl trichloroacetimidates under very mild conditions. This reagent proved effective in promoting the glucosylation of saccharidic acceptors 2, 3, 4, and 5, possessing primary or secondary hydroxyls, with the model donor 1. The stereoselectivity of these glycosidations can be controlled by a suitable choice of solvent.