Synthesis of diverse asparagine linked oligosaccharides and synthesis of sialylglycopeptide on solid phase

Oligosaccharides are linked to the protein surface and play roles in a number of biological events. Therefore, much attention is being paid to research to investigate the function of the oligosaccharides. In order to investigate the function of oligosaccharides, many synthetic approaches have been examined by synthesizing O-linked or N-linked glycopeptides. Synthesis of O-linked type oligosaccharides is relatively feasible compared to that of N-linked oligosaccharides, because the number of sugar components in the former oligosaccharides is small. In the biosynthesis of oligosaccharides, only N-linked oligosaccharide is reconstructed from the high mannose-type to the hybrid and complex types at the Golgi apparatus. This scientific question, namely, why only N-glycan should change its structure, has been paid much attention and convenient synthesis for both N-glycan and glycopeptide having N-glycans has been examined in order to study the role of N-glycan. In this review, we would introduce recent synthetic developments focusing on the synthesis of N-linked glycopeptides and its analogues.