Thermodynamically Controlled Regioselective Glycosylation of Fully Unprotected Sugars through Bis(boronate) Intermediates

Abstract

Abstract Fully unprotected D ‐glucose, D ‐mannose, and D ‐fructose were regioselectively glycosylated with several phenylthioglycosides to afford glycosyl‐β(1→6)‐α/β‐ D ‐glucopyranose, glycosyl‐β(1→1)‐α‐ D ‐mannofuranoside, and glycosyl‐β(1→1)‐β‐ D ‐fructopyranose in good yields. The regioselectivity might have arisen from a thermodynamically controlled bis(phenylboronate) intermediate, which leaves only one free hydroxy group to be glycosylated in complete regioselectivity.