24 糖タンパク糖鎖の高効率合成(口頭発表の部)

抄録

Glycoprotein oligosaccharides constitute a group of highly diverse structures. Aiming at the development of efficient synthetic methodologies for this biologically important class of molecules, our research activities have been directed to 1) stereoselective formation of β-manno glycoside and its application into convergent synthesis of asparagine-linked glycans, and 2) polymer-support synthesis of oligosaccharide. β-Manno glycosylation was achieved in a fully stereocontrolled manner, by using a P-methoxybenzyl (PMB) group as a stereocontrolling element. Thus, 2-O-PMB carrying mannosyl donors 2,8, and 9 afforded 4, 11-14 as a single stereoisomer, by treatment with DDQ in the presence of appropriate aglycon, followed by activation of the anomeric position. These products were further converted into core structure of asparagine-linked glycans 18, 19, and 21. Orthogonal glycosylation strategy previously reported by ourselves was applied into polymer-support synthesis of glycoprotein related oligosaccharides 28 and 29. Known chloride 22 was converted into polyethylene glycol-linked 24. Sequential glycosylation with 25 and 26 afforded 27, which was deprotected into 28. The existence of hydrophobic aglycon as a tag at the anomeric position enabled us to fish up the desired oligosaccharide in a simple manner by using reverse phase column. Tetrasaccharide 29 was also synthesized in a similar manner.