Formation of O-glycosidic linkages from 1-hydroxy sugars by bismuth(III) triflate-catalyzed dehydrative glycosidation

This paper describes the direct formation of various O-glycosidic linkages from 1-hydroxy sugars by bismuth(III) triflate-catalyzed dehydrative glycosidation. The condensation reactions of 1 -hydroxy sugars with some primary alcohols in the presence of only 5 mol% bismuth(III) triflate at reflux temperature for 15 min in dichloromethane afforded O-glycosides in good yields. An 1,6-anhydro-β-D-glucopyranosidic linkage was formed by the intramolecular condensation of the corresponding 1-hydroxy sugar performed with similar reaction conditions using 5 mol% bismuth(III) triflate. A reaction using 10 mol% bismuth(III) triflate at room temperature in dichloromethane promoted the self- or cross-condensations of 1-hydroxy sugars to produce several kinds of 1,1′-disaccharides. This paper reports some important properties of bismuth(III) triflate catalyzed dehydrative glycosidation using 1-hydroxy sugars to form various O-glycosidic linkages.