A facile H 2SO 4-SiO 2-catalyzed ferrier rearrangement of 3,4,6-Tri- O -benzyl-d-glucal

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 (<2h) and efficiently (>62%) in good -selectivity (/>4.2:1) under mild conditions.