Dy(OTf)(3)-immobilized in ionic liquids: a novel and recyclable reaction media for the synthesis of 2,3-unsaturated glycopyranosides

D-Glycals react smoothly with a variety of alcohols, phenols and hydroxy alpha-amino acids in the presence of 5 mol% dysprosium triflate immobilized in 1-butyl-3-methylimidazolium hexafluorophosphate under mild reaction conditions to afford the corresponding 2,3-unsaturated glycopyranosides in excellent yields with high alpha-selectivity. The catalyst immobilized in ionic liquids was recycled in subsequent reactions without any apparent loss of activity.