CHEMOENZYMATIC SYNTHESIS OF THE BRANCHED OLIGOSACCHARIDES WHICH CORRESPOND TO THE CORE STRUCTURES OF N-LINKED SUGAR CHAINS

Synthetic routes are described to a partial structure common to all hi gh mannose-type sugar chains and complex-type sugar chains based on a chemoenzymatic strategy which incorporates, (a) enzymatic synthesis of oligosaccharide blocks using glycosidases, and (b) chemical synthesis of the branching oligosaccharides via regioselective coupling. All re action products correspond to key intermediates necessary for the cons truction of N-linked oligosaccharides and we have synthesized the bran ched tetra-manno-oligosaccharide high mannose-type sugar chain and the branched hexa-oligosaccharide complex-type sugar chain using this sim ple and direct method. (C) 1998 Elsevier Science Ltd.