New Method for Regioselective Glycosylation Employing Saccharide Oxyanions

Abstract As an alternative concept for glycosylation, the prior activation of acceptor hydroxy groups for selective glycosidic bond formation, was investigated to give complex oligosaccharides. Oxyanions obtained from partially protected saccharides were glycosylated by employing glycopyranosyl halides, and the regiochemical results were studied. Initially, partially methylated methyl‐α‐ D ‐glucopyranosides were used as a model system to study the underlying mechanistic principles of base‐promoted glycosylation. High regioselectivities and stereospecific glycosidic bond formations were achieved, and the scope of the methodology was extended with different perbenzylated glycosyl donors.