Stereospecific solution- and solid-phase glycosylations. Synthesis of beta-linked saccharides and construction of disaccharide libraries using phenylsulfenyl 2-deoxy-2-trifluoroacetamido glycopyranosides as glycosyl donors

An efficient strategy to construct beta-O-2-amino-2-deoxyglycopyranosidic l inkages using glycosyl sulfoxides is demonstrated. Phenylsulfenyl 2-deoxy-2 -trifluoroacetamido glycopyranosides were found to be reactive glycosyl don ors in both solid- and solution-phase glycosylations, affording the corresp onding beta-glycosides exclusively and in high yield. The trifluoroacetamid o group was removed under mild conditions, allowing orthogonal derivatizati on of multiple protected amino groups on an oligosaccharide or glycoconjuga te. On the basis of the results with these glycosyl donors, a solid-phase b eta-linked disaccharide library was constructed. The scope and flexibility of this approach will be discussed.