Synthesis of 6-Sulfonatomethyl Thioglycosides by Nucleophilic Substitution: Methods to Prevent 1→6 Anomeric Group Migration of Thioglycoside 6-<i>O</i>-Triflates
position of thioglycosides by nucleophilic displacement of the corresponding 6-O-triflate is described. The 1→6migration of the anomericgroup, which inevitably occurs through a bicyclic sulfonium ion intermediate, from conformationally flexible β-thioglycosides was prevented by using an α-thioglycoside or conformationally locked β-thioglycoside as the starting material. The thioglycoside 6-sulfonic