Nitrile biotransformations for the synthesis of enantiomerically enriched Baylis–Hillman adducts

Abstract

Catalysed by the nitrile hydratase/amidase-containing Rhodococcus sp. AJ270 cells, a number of β-aryl- and β-alkyl- β-hydroxy-α-methylenepropiononitriles (the Baylis–Hillman nitriles) 1 underwent hydrolysis under mild conditions to produce the corresponding enantiomerically enriched Baylis–Hillman amides 2 and acids 3. The enantioselectivity of the biotransformations was strongly determined by the steric effect of the substituents at the β-position of the substrates. The protection of the free hydroxy of β-phenyl-β-hydroxy-α-methylenepropiononitrile 1a by methylation led to the enhancement of enantiocontrol of the biohydrolysis.