One-pot chemo-enzymatic enantiomerization of racemates

A new one-pot chemo-enzymatic procedure was developed for enantiomerization of racemates based on enzymatic enantiospecific oxidation of a substrate and chemical non-enantiospecific reduction of the product. The principle is shown as follows for the L-proline production. [GRAPHICS] L-Proline and L-pipecolate were produced from racemic proline and pipecolate by means of D-amino acid oxidase and sodium borohydride in high yield in this reaction system [J.W. Huh, K. Yokoigawa, N. Esaki, K. Soda, Biosci., Biotechnol., Biochem. 56 (1992) 2081], DL- and L-Lactate were DL-enantiomerized in a one-pot reaction system containing L-lactate oxidase and sodium borohydride in the similar manner [S. Mukoyama, K. Yamanaka, T. Oikawa, K. Soda, Nippon Nogei Kagaku Kaishi 73 (1999) 62]. Pyruvate was also converted to an equimolar amount of D-lactate in the same system. D-cr-Hydroxybutyrate can be produced from the DL- and L-isomers, and alpha -ketobutyrate in the same manner though slowly. This method is applicable to production of other chiral compounds from the corresponding racemates. (C) 2001 Elsevier Science B.V. All rights reserved.