Regio‐ and Stereochemical Controlled Koenigs–Knorr‐Type Monoglycosylation of Secondary Hydroxy Groups in Carbohydrates Utilizing the High Site Recognition Ability of Organotin Catalysts

The catalytic regio‐ and stereoselective monoglycosylation of carbohydrates using organotin catalysts is demonstrated. The one‐step reaction affords various oligosaccharides linked at the secondary hydroxy group in high chemical yield and good regio‐ and stereoselectivities. The regioselectivity of the glycosylation is shown to depend on the spatial arrangement of the hydroxy groups in the carbohydrates.