Divergent Reactivity of a Dinuclear (NHC)Nickel(I) Catalyst versus Nickel(0) Enables Chemoselective Trifluoromethylselenolation

We herein showcase the ability of NHC-coordinated dinuclear Ni-I-Ni-I complexes to override fundamental reactivity limits of mononuclear (NHC)Ni-0 catalysts in cross-couplings. This is demonstrated with the development of a chemoselective trifluoromethylselenolation of aryl iodides catalyzed by a Ni-I dimer. A novel SeCF3-bridged Ni-I dimer was isolated and shown to selectively react with Ar-I bonds. Our computational and experimental reactivity data suggest dinuclear Ni-I catalysis to be operative. The corresponding Ni-0 species, on the other hand, suffers from preferred reaction with the product, ArSeCF3, over productive cross-coupling and is hence inactive.