Ionic Liquids in Methyltrioxorhenium Catalyzed Epoxidation-Methanolysis of Glycals under Homogeneous and Heterogeneous Conditions

The efficient and high yielding domino epoxidation–methanolysis of glycals has been achieved under environment friendly conditions by oxidation with urea hydrogen peroxide adduct (UHP) andH2O2 in ionic liquids (ILs) catalyzed by methyltrioxorhenium and different heterogeneous methyltrioxorhenium derivatives. The facial diastereoselectivity of the oxidation ranged from satisfactory to excellent ones depending on the substrate and could be optimized by ample screening of catalysts. The oxidations performed with UHP proceeded with a higher degree of diastereoselectivity than those performed with H2O2. High yields of products and conversions of substrates were obtained under mild experimental conditions and by the use of simple work-up procedures.