Enantioselective Synthesis of (R)‐2‐Arylpropanenitriles Catalysed by Ene‐Reductases in Aqueous Media and in Biphasic Ionic Liquid–Water Systems

The enantioselective reduction of α‐methylene nitrile derivatives catalysed by ene‐reductases affords the corresponding ( R )‐2‐arylpropanenitriles with high conversion values. The reaction is investigated either in aqueous medium (with an organic cosolvent or by loading the substrate onto hydrophobic resins) or in a biphasic ionic liquid–water system. The use of ionic liquids, herein with isolated ene‐reductases, is found to improve the work‐up and the substrate recovery method. The synthetic manipulation of the final chiral nitrile derivatives indicates how this biocatalysed method can be exploited for the preparation of a wide range of chiral compounds.