The nitrile compounds are present in a variety of biologically active natural products and pharmaceuticals, and the nitrile groups are versatile synthetic intermediates to other functionalized compounds. Herein, the asymmetric reduction of α,β-unsaturated nitriles with water as a hydrogen source is reported. The reaction is catalyzed by the complex of [Ir(COD)Cl]2 and (Ra, S)-Ph-Bn-SiPhox, and allows the preparation of useful enantioenriched chiral 3,3-disubstituted propionitriles with high optical purities in mild conditions.