O‐Glycoside Synthesis under Neutral Conditions in Concentrated Solutions of LiClO4 in Organic Solvents Employing O‐Acyl‐Protected Glycosyl Donors

Abstract

AbstractO‐Glycosides of pivaloyl‐protected glucose can be synthesized under neutral conditions in moderate yields by employing the pivaloylated β‐glucosyl fluoride 2d and the respective β‐benzyl phosphate 2e as glycosyl donors and 1 M solutions of LiClO4 in CH2Cl2 or CHCl3 as reaction media. The acetyl‐protected α‐ or β‐configured glucosyl trichloroacetimidates 1a and 1b were converted into the orthoesters 6 which were isolated in moderate to high yields. Under these conditions, acetyl‐protected glycosyl phosphates, acetyl‐ or pivaloyl‐protected glycosyl bromides and O‐pivaloylated glycosyl trichloroacetimidates were not converted to the desired O‐glycosides.