Catalytic Hydrogenation of Carboxamides with a Bifunctional Cp*Ru Catalyst Bearing an Imidazol-2-ylidene with a Protic Aminoethyl Side Chain

Synthesis of a Cp* Ru complex bearing an NH2-functionalized N-heterocyclic carbene (C-NH) was achieved by treatment of Cp* RuBr( isoprene) with an equimolar amount of a silver complex, which was generated from Ag2O and 1-(2-aminoethyl)-3-methylimidazolium bromide, in CH3CN at room temperature. The new Cp* RuBr(C-NH) complex showed a higher catalytic performance than the related Cp* RuCl( P-NH) and Cp* RuCl(N-NH) complexes. In the reaction of Narylcarboxamides, the amine products were obtained in satisfactory yields under mild temperature conditions.