Ni(II)-(sigma-aryl) complex: a facile, efficient catalyst for nickel-catalyzed carbon-nitrogen coupling reactions.

trans-Haloarylbis(triphenylphosphine)nickel(II), a type of air- and moisture-stable Ni(II)-(sigma-aryl) complex, was examined as catalyst precursor in the C-N coupling reaction. This type of Ni(II) pre-catalyst, associated with N-heterocyclic carbene ligands, is found to easily produce the catalytically active Ni(0) species in situ without the aid of external reductants and allows for the efficient amination of aryl chlorides with secondary cyclic amines and anilines under mild conditions.