20 糖脂質糖鎖の合成研究(口頭発表の部)

概要

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1. Synthesis of a common glycan chain of I-active glycolipid. I-Active glycolipid which is the representative of the glycoconjugates carrying lactosamine as a repeating unit contains a common branched glycan chain 1. In order to develop the strategy for the synthesis of such a glycan chain, a lactosamine synthon 2 was designed and synthesized from monosaccharide precursors. The versatility of 2 was demonstrated by the synthesis of the octasaccharide 1. 2. Sulfenate esters as glycosyl acceptors. A novel approach to the synthesis of glycosylated products was developed by the Lewis acid mediated activation of sulfenate esters 15. The reaction of 15 with glycals 16 gave 2-deoxy-2-phenylthioglycosides 18 which are potential precursors of 2-deoxyglycosides. Thioglycosides 17 also reacted with 15 and 0-glycosides 19 were obtained under mild conditions. The stereoselectivity was found to be dependent on the solvent employed. 3. Stereoselective synthesis of α-glycosides of sialic acid. Sialic acid is an important constituent of glycolipids. However, the stereoselective glycosylation of sialic acid is difficult to achieve. In order to solve this problem by neighbouring group participation, we designed 20 which in turn was synthesized from 2,3-dehydro derivative 21. The reactions of 20 with glycosyl acceptors gave α-glycosides exclusively.
天然有機化合物討論会の論文
1987-07-25