Total asymmetric synthesis of monosaccharides and analogues

Since the discovery of the 'formose reaction' by Butlerow,[1] total synthesis of carbohydrates has undergone rapid development. The most important methods for the asymmetric synthesis of monosaccharides and analogues of biological importance are presented. Nowadays any natural and non-natural monosaccharide can be prepared pure in both enantiomeric forms starting from inexpensive starting materials. Metal-based asymmetric catalysis and organocatalysis have been successfully applied, alone or in combination with chemoenzymatic methods. Alternative methods rely upon substrate- or reagent- controlled diastereo- and enantioselective reactions. Suitably protected carbohydrates have been prepared by total synthesis, thus allowing their direct use in the preparation of oligosaccharides and analogues.