7.24 Enantioselective Hybrid Catalysts

Hybrid catalysts, based on the incorporation of a catalytically active synthetic fragment within a host protein, lie at the interface between homogeneous and enzymatic catalysis. In terms of the activity, reaction repertoire, substrate range, and operating conditions, they take advantage of the versatility of chemical catalysis. In contrast, the enantioselectivity is determined by the biomolecular scaffold, which confers the catalytic moiety with a well-defined second coordination sphere, reminiscent of enzymes. The attractive feature of such systems is their optimization potential, which combines chemical and genetic methods (i.e., chemo-genetic) to screen diversity space. In this chapter, the various methods that have been used for the design of hybrid catalysts will be described, with a focus on the creation of artificial metalloenzymes, based on the incorporation of transition metal complexes into a biomolecular scaffold. An overview of the synthetic applications of hybrid catalysts in asymmetric catalysis will be provided.