Fan Linfeng, Hindsgaul Ole
Department of Chemistry, University of Alberta, Edmonton, Canada.
Org Lett. 2002 Dec 12;4(25):4503-6. doi: 10.1021/ol0270430.
[structure: see text] A protocol for the synthesis of novel cyclic beta-1,6-S-linked glucopyranosides is developed. The key intermediate is a linear thiooligosaccharide bearing an iodo group at C-6 of the nonreducing sugar and a thioacetyl group at the anomeric center of the reducing end sugar. The crucial macrocyclization step was achieved through base-promoted intramolecular S(N)2 glycosylation in remarkably high yields (92-95%) and with well-controlled stereochemistry.
[结构：见正文] 开发了一种新型环状β-1,6-S-连接的吡喃葡萄糖苷的合成方案。关键中间体是一种线性硫代寡糖，在非还原糖的C-6位带有碘基团，在还原端糖的异头中心带有硫代乙酰基。关键的大环化步骤通过碱促进的分子内S(N)2糖基化以极高的产率（92-95%）和良好控制的立体化学得以实现。
