Sulfuric acid immobilized on silica: an excellent catalyst for Fischer type glycosylation

Fischer glycosylation, a widely used technique for the preparation of simple alkyl or aryl glycosides, has a few drawbacks including the use of strong mineral acids, excess alcohols, high temperature and long reaction times. This manuscript highlights a modification using sulfuric acid immobilized on silica as catalyst for the preparation of glycosides from free sugars such as D-glucose, D-galactose, D-mannose, L-rhamnose, L-fucose, N-acetyl-D-glucosamine and D-maltose with a diverse range of alcohols to afford a series of useful sugar derivatives in good to excellent yields. (C) 2007 Elsevier Ltd. All rights reserved.