Ruthenium N-heterocyclic carbene catalysts for selective reduction of nitriles to primary amines

Easily accessible in situ catalysts composed of [Ru(cod)(2-methylallyl)2] and N-heterocyclic carbene ligands have been developed for the environmentally benign hydrogenation of various nitriles to give primary amines. Applying optimized conditions in the presence of SIMesBF4 as ligand high catalyst activity of up to 392 h−1 is achieved in the hydrogenation of benzonitrile. The general applicability and functional group tolerance of this novel catalyst system are shown in the reduction of ten different nitriles.