Nucleophilic Addition of Potassium Alkynyltrifluoroborates to <scp>d</scp>-Glucal Mediated by BF₃·OEt₂: Highly Stereoselective Synthesis of α-<i>C</i>-glycosides

Abstract

A convenient, mild and highly stereoselective method for C-glycosidation (alkynylation) of D-glucal with various potassium alkynyltrifluoroborates, mediated by BF3x OEt2 and involving oxonium intermediates, preferentially provides the alpha-acetylene glycoside products with good yields.