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Enzymes are biodegradable and renewable resources that utilize water as the reaction solvent. Reactions catalyzed by enzymes are among the most effective, selective, and 'green' processes available today. The advantages of using biocatalysts include their high degree of regio- and stereo-specificity, versatility, and high reaction rates under mild reaction conditions. Enzyme catalyzed enantioselective C-C bond formation reactions are rather important aspects of synthetic organic chemistry. Thiamine pyrophosphate (TPP) dependent enzymes, especially, have an important role in the stereo-selective formation of C - C bonds. This review covers the recent advances in enzyme catalyzed asymmetric C-C bond formation using the most pronounced thiamine pyrophosphate dependent enzymes: acetohydroxyacid synthase, benzaldehyde lyase, benzoylformate decarboxylase, pyruvate decarboxylase, and phenylpyruvate decarboxylase. These enzymes are all capable of acyloin-type condensation reactions in water under mild conditions, in turn leading to chiral a-hydroxy ketones, which are versatile building blocks for the pharmaceutical and chemical industries. |
