Copper‐Catalyzed Highly Selective Semihydrogenation of Non‐Polar Carbon‐Carbon Multiple Bonds using a Silane and an Alcohol

Abstract A copper catalyst bearing a suitable Xantphos derivative or NHC ligand was found to be highly efficient for the selective semihydrogenation of non‐polar unsaturated compounds using a mixture of a silane and an alcohol as reducing agent. The catalytic system was useful for the selective semihydrogenation of internal alkynes to ( Z )‐alkenes with suppression of overreduction to the corresponding alkanes. Furthermore, semihydrogenations of terminal alkyne, 1,2‐diene, 1,3‐diene, 1,3‐enyne and 1,3‐diyne systems were also achieved selectively.