Owing to the driving force of the Ferrier-type rearrangement, the exo-glycals are highly reactive with various alcohols to afford glycosides and glycoconjugates with exclusive -configuration. The resulting vinyl group in these glycosylation products can be further elaborated for general applications, including the synthesis of spiro derivatives and glycosylation of 2-ketoaldonic acids. Our current method is applicable to the synthesis of disaccharides, glycolipids, and glycopeptides having quaternary anomeric centers.i A number of natural products and enzyme inhibitors have been prepared from the exo-glycals, for example FR901464, narciclasine, lycoricidine, pancratistatin, psammaplysin, Reveromycins A and B etc.ii As a result, the development glycosylation of exo-glycals is important topic. Herein we demonstrate that such exo-glycals undergo glycosylation reactions to give novel glycosides and glycoconjugates with excellent stereoselectivity.
