Synthesis of 2,3-Unsaturated Alkynyl O-Glucosides from Tri-O-acetyl-D-glucal by Using Montmorillonite K-10/lron(lll) Chloride Hexahydrate with Subsequent Copper(l)-Catalyzed 1,3-Dipolar Cycloaddition

摘要

Two strategies were considered for the synthesis of 2,3-un-saturated O-glucosyl-1,2,3-triazoles. The first, involving reaction between tri-O-acetyl-D-glucal and triazole alcohols gave no stereoselectiv-ity. A second strategy provided 2,3-unsaturated O-glycosides from glycals and alkynols through a Ferrier rearrangement; this method, employing montmorillonite K-10 doped with iron(lll) chloride hexahydrate in dichloromethane afforded new glycosides in good to excellent yields within short times and with high a-stereoselectivities. Subsequently, the glucosides were coupled with 2-azido-1,4-naphthoquinone to produce a new series of 1,2,3-1 H-triazolyl O-glucoside derivatives through a click reaction.