1,2-cis O-glycosylation:: Methods, strategies, principles

The aim of this review is to discuss the accomplishments made in the area of the stereoselective formation of a 1,2-cis glycosidic bond. Importance of this subject derives primarily from the natural occurrence of numerous 1,2-cis-linked oligosaccharides, glycosides, and glycoconjugates, which are widely distributed in living tissues. These compounds are also found in the human milk, in blood group compounds, in bacterial lipopolysaccharide antigens, and many other sources. A great number of reviews and book chapters dedicated to the oligosaccharide synthesis have recently emerged, and therefore general aspects of the glycosidic bond formation are discussed only up to a certain extent. Instead, this review is focused primarily on the,glycosylation methods for the synthesis of 1,2-cis glycosides, which are traditionally underrepresented in the literature.