Nitrile and Amide Biotransformations for Efficient Synthesis of Enantiopure gem‐Dihalocyclopropane Derivatives

Catalyzed by Rhodococcus sp. AJ270 microbial cells, trans‐2,2‐dihalo‐3‐phenylcyclopropanecarbonitriles and ‐amides underwent enantioselective hydrolysis under very mild conditions. Both the efficiency and enantioselectivity of the nitrile hydratase and amidase involved in the cells were strongly determined by the nature of the halogen substituent. The synthetic utility of the biocatalytic process was illustrated by an efficient and multi‐gram scale biotransformation and synthesis of enantiopure 2,2‐dichloro‐3‐phenylcyclopropanecarboxylic acid and amide in both enantiomeric forms.