45. Transition-Metal-Catalyzed Transformation of Monosaccharides and Polysaccharides

The exploitation of transition metals in carbohydrate chemistry has achieved considerable developments in the last decades. This contribution gives an overview of transition-metal-catalyzed transformations of various mono- and polysaccharides into enantiopure compounds, fine chemicals, and building blocks suitable for industrial application. These recent applications in this area have made this field of chemistry very attractive. The utilization of carbohydrate–transition-metal complexes have become a powerful tool for forming and breaking of the carbon–carbon bonds. Particular attention is given to recent developments and advances in the use of Mo(VI) ions as highly stereospecific catalyst in carbohydrate synthesis, highlighting the representative examples from the last decade. In the second part, the review describes transition-metal catalytic systems that are involved in the of transformation natural polysaccharides (cellulose, starch, xylans) into important organic intermediates (5-hydroxymethylfurfural, furfural). It is shown that particularly the application of Mo(VI)-catalytic system, in combination with microwave irradiation, in transformation of starch and xylans offers interesting alternative for the preparation of valuable of monosaccharides and corresponding alditols (mannose, xylose, lyxose, mannitol, xylitol, lyxitol). The emphasis is primarily placed on high stereoselectivity in catalytic reactions and transformation of renewable carbohydrate biomass as promising source of organic raw materials for production of useful platform chemicals, rare sugars, and fuels.