Perfectly Regioselective and Sequential Protection of Glucopyranosides

A perfectly regioselective and sequential method for the preparation of orthogonally protected glucopyranosides has been developed. An acyl group was introduced at C(4)-OH by organocatalysis with >99 % regioselectivity. TBDPS, Boc, and BOM groups were sequentially introduced into the 4-O-acyl-glucopyranoside at C(6)-OH, C(2)-OH, and C(3)-OH, respectively, with ca. 100 % regioselectivity in each step.