Biotransformations

Abstract

This report reviews significant developments in applications of biological catalysis in synthetic organic chemistry for the year 2010. Hydrolases have been applied in kinetic resolution and quantitative DKR processes and have been evolved in vitro to give enzymes displaying improved enantioselectivity and solvent stability. Applications of reductases have included an unusual instance of the generation of optically active atropisomers and also the identification of stereoselective imine reductases in Streptomyces spp. Other biotransformations leading to optically active amines have focused on transaminases, and a wide-ranging genomics analysis has revealed nineteen new and previously rare (R)-selective transaminases. A further (R)-selective transaminase was extensively engineered for process suitability for application in the industrial synthesis of sitagliptin. Improved carbon–carbon bond formation by aldolases is being addressed through the identification and improvement of enzymes accepting non-phosphorylated dihydroxyacetone as a substrate donor for the synthesis of sugars. In addition, new enzymatic activities, including natural enzymes that catalyse the Stetter reaction, and also the Michael-type addition of water to cyclohexenone have been reported. Finally, advances in the in silico design of enzymes are proceeding rapidly, with the report of the design of the first enzyme known to catalyse an bimolecular Diels-Alder reaction.