Enantioselective biotransformations of racemic alpha-substituted phenylacetonitriles and phenylacetamides using Rhodococcus sp AJ270

Rhodococcus sp. AJ270 is an efficient whole-cell system able to catalyze th e stereoselective conversions of racemic alpha-substituted phenylacetonitri les and amides under very mild conditions into enantiopure carboxylic acids and derivatives. The nitrile hydratase involved generally has a broad subs trate spectrum against phenylacetonitriles irrespective of the electronic n ature of the alpha-substituent while the amidase is very sensitive to both the electronic and steric factors of the substituent of amides. The overall enantioselectivity of nitrile hydrolysis is mainly determined by the combi nation of selectivities of nitrile hydratase and of amidase, with the latte r being a major contributor. The amidase has high S-enantiocontrol against amides while the nitrile hydratase exhibits low R-selectivity against nitri les. The scope and limitations of this enantioselective biotransformation p rocess are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.