Inorganic asymmetric reduction

Catalytic asymmetric reduction of unsaturated compounds is one of the most reliable methods used to synthsize the corresponding chiral saturated products. Chiral transition metal complexes repeatedly activate an organic or inorganic hydride source, and transfer the hydride to olefins, ketones, or imines from one... 

Table 2.1 Examples of heterogeneous asymmetric reduction using inorganic supports. 

Metal alkoxides have a well-established role in catalytic reactions. In Chapter 7, a brief review on the history, characteristics and synthetic routes for preparing metal alkoxides are illustrated. The catalytic processes performed by these catalysts include polymerization of different olefin oxides and cyclic esters, asymmetric reduction of aldehydes and ketones, oxidation of sulfides and olefins, and a variety of asymmetric reactions. The remainder of the chapter discusses characteristics of these catalytic systems. Other challenges separate from the metal alkoxide catalysis involve development of catalytic protocols in solvent-free or in green solvent conditions, viz., H O or liquid CO. The second challenge is recovery of catalyst without loss of its activity. Supporting metal alkoxide onto inorganic solids, especially magnetic ones, may effectively solve the later problem. 

Since tlie first successful report on heterogeneous asymmetric hydrogenation using inorganic materials by Kinting et al. in 1985 [22], numerous advances have been made in this area of research. Some representative examples of chiral reduction catalysts immobilized on inorganic support are summarized in Table 2.1. As... 

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