Silicon Fluorides for Acid-Base Catalysis in Glycosidations

Adduct formation between alcohols as glycosyl acceptors and phenylsilicon trifluoride (PhSiF3) as catalyst permits acid-base-atalyzed glycosidations with O-glycosyl trichloroacetimidates as glycosyl donors. In this way, from various glycosyl donors and acceptors 1,2-trans- and some 1,2-cis-glycosides could be obtained with high anomeric selectivity. A preference for an intramolecular bimolecular nucleophilic substitution (SN2-type) reaction course with concomitant donor and acceptor activation is supported by the results.