Dinuclear Systems in the Efficient Nickel-Catalyzed Kumada–Tamao–Corriu Cross-Coupling of Aryl Halides

Highly
active dinuclear nickel­(I) complexes bearing bulky N-heterocyclic
carbene ligands have been shown to be involved in the catalytic cycle
of the Kumada–Tamao–Corriu cross-coupling reaction of
aryl halides. The results of several stoichiometric reactions and
kinetics experiments have revealed that monovalent and divalent dinickel
species are the active species in the highly efficient, nickel-catalyzed,
Kumada coupling reactions of aryl halides.