Systematic synthesis of ER related N-glycans using convergent strategy

In this review, systematic synthesis of the ER type of asparagine linked sugar chains are described. The function of asparagine linked sugar chains in the glycoprotein quality control process has recently attracted attention. To construct the target sugar chains, we employed a convergent and stereoselective manner, using four oligosaccharide components, core trisaccharide having a P-mannoside bond, a linear mannotriose, branched manno-oligosaccharide derivatives, and glucose derivatives. Hexasaccharide acceptor was employed as the common intermediate, and coupling with branched manno-oligosaccharide derivatives such as M5, M4B, or WC donor afforded high-mannose type glycans, corresponding to undecasaccharide M9, dodecasaccharide M8B and M8C, respectively. Finally, synthesized high mannose type sugar chains and glucose derivatives were combined to glucosylated high mannose type glycans of arbitral structures.