Recent development of stereoselective glycosylation reactions

Carbohydrates are the most abundant class among biological molecules. Advances in glycobiology have revealed the vital roles played by glycosides and glycoconjugates in biological events. In this context, access to homogenous oligosaccharides and glycoconjugates is critical for various biological investigations. Glycosylation is the cornerstone of glycoside synthesis, and during glycosylation, the control of stereoselectivity at the anomeric position is highly important. In this review, recent progresses in 1,2-cis-glycosylation reactions are summarized, with a focus on the influence of the protecting groups on the conformations of the glycosyl donors, role of reaction mixture additives, and synthetic utility of endocyclic cleavage of glycoside. Development of robust glycosylation reaction will contribute to biologically active oligosaccharide synthesis.