Pyridin- and quinolinylidene nickel carbene complexes as effective catalysts for the Grignard cross-coupling reaction

A series of complex compounds that contain N-heterocyclic carbene (NHC) and N-heterocyclic carbene ligands with a remote heteroatom (rNHC) have been prepared in good yields and characterized. [Cl(NHC)(PPh3)2Ni]BF4 and [Cl(rNHC)(PPh3)2Ni]BF4 also combine the stability of carbene complexes with the activity of phosphine complexes and some are active and effective precatalysts for aryl-coupling in the Kumada–Corriu reaction. Aryl chlorides can be used as substrates. Their performance in catalysis as well as their easy preparation make the new compounds superior to other comparable mixed carbene–phosphine compounds known thus far.

Graphical abstractA series of nickel(II) compounds that contain N-heterocyclic carbene (NHC) and N-heterocyclic carbene ligands with a remote heteroatom (±NHC) have been prepared in good yields and characterized. They provide active pre-catalysts for the Kumada–Corriu reaction; arylchlorides can be used as substrates. Figure optionsDownload full-size imageDownload as PowerPoint slide