Total asymmetric synthesis of monosaccharides and analogues

Since the discovery of the 'formose reaction' by Butlerow, 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.