The mechanism of the reactions between dppf-Ni 0 complexes and alkyl halides has been investigated using kinetic and mechanistic experiments and DFT calculations. The active species is [Ni(κ 2 -dppf)(κ 1 -dppf)], which undergoes a halide abstraction reaction with alkyl halides and rapidly captures the alkyl radical that is formed. The rates of the reactions of [Ni(COD)(dppf)] with alkyl halides and the yields of prototypical nickel-catalyzed Kumada cross-coupling reactions of alkyl halides are shown to be significantly improved by the addition of free dppf ligand.

The reactions of nickel(0) complexes with phosphine, bipyridine-type, and N-heterocyclic carbene ligands with aryl, vinyl, and alkyl halides is reviewed.