A Facile H₂SO₄-SiO₂–Catalyzed Ferrier Rearrangement of 3,4,6-Tri-<i>O</i>-benzyl-d-glucal

Abstract

Sulfuric acid immobilized on silica gel (H2SO4-SiO2) was used as an efficient and convenient promoter for Ferrier-type rearrangement of 3,4,6-tri-O-benzyl-d-glucal in CH2Cl2, which is a difficult donor for this type of reaction. The acceptors include primary alcohols, secondary alcohols, pentanol, halogenated alcohol, sterols, thiol, and 2-naphthol. Thus, 2,3-unsaturated glycosides were obtained rapidly (<2 h) and efficiently (>62%) in good α-selectivity (α/β>4.2:1) under mild conditions.