A wide range of biological and physical functions are generated through precise molecular recognition that requires strict matching of chirality. Therefore, discovery of truly efficient methods of obtaining chiral substances is a substantial challenge for synthetic chemists.
Asymmetric catalysis is an ideal way for synthesizing optically active compounds.
In 1966 Noyori presented for the first time a general principle for chemical multiplication of chirality as illustrated in Figure 1 . The chemical approach, which uses a very small amount of an asymmetric molecular catalyst, produces natural and unnatural compounds in large quantities. Since chirality is a crucial issue in bioactive molecules, this homogeneous asymmetric catalysis is very powerful in pharmaceutical, agrochemical, flavor, and fragrance industries. The efficiency of the chemical method using man-made molecular catalysts rivals or, in certain cases, even exceeds that of natural enzymatic reactions. Thanks to the diverse catalytic activities of metallic species, coupled with the virtually unlimited permutability of the chiral organic ancillaries, the possibilities and the opportunities that asymmetric catalysis affords are enormous.