Highly efficient conjugate reduction of (alpha),(beta)-unsaturated nitriles catalyzed by copper/xanthene-type bisphosphine complexes

(alpha),(beta)-Unsaturated nitriles are chemoselectively reduced to the corresponding saturated nitriles in high yields using a copperDPEphos or Xantphos complex as catalyst in the presence of polymethylhydrosiloxane (PMHS) as the stoichiometric reducing agent and t-butanol as additive.