LITHIUM TRIFLATE AS A NEW PROMOTER OF GLYCOSYLATION UNDER NEUTRAL CONDITIONS

The glycosyl donors 2,3,4,6-tetra-O-benzyl-alpha-D-glucopyranosyl tric hloroacetimidate and 3,4,6-tri-O-benzyl-alpha-D-fucopyranosyl trichlor oacetimidate were activated under neutral conditions with a catalytic amount (0.05 equiv) of lithium triflate and reacted with a series of a lcohols including an acid sensitive sugar to give the corresponding gl ycosides in high yields. The stereoselectivity of the glycosylation wa s improved by introducing a participating group next to the anomeric p osition.