Total synthesis of 4d-deoxy Lewis~x pentasaccharide

摘要

Total synthesis of 4d-deoxy Lewis~x pentasaccharide is described. O-(2,3,6-Tri-O-benzoyl-4-deoxy-α-D-xylo-hexopyranosyl)tri-chloroacetirnidate was condensed with a diol of glucosamine to give regioselectively a β1→ 4 linked disaccharide, which was further fucosylated to a protected deoxy Lewis~x trisaccharide. A highly stereo- and regioselective glycosylation of this trisaccharide onto a lactoside diol was performed to provide a pentasaccharide in excellent yield. After deprotection, this pentasaccharide afforded the target oligosaccharide.