Unexpected nickel complex speciation unlocks alternative pathways for the reactions of alkyl halides with dppf-nickel(0)

Greaves, Megan E. and Ronson, Thomas O. and Lloyd-Jones, Guy C. and Maseras, Feliu and Sproules, Stephen and Nelson, David J. (2020) Unexpected nickel complex speciation unlocks alternative pathways for the reactions of alkyl halides with dppf-nickel(0). ACS Catalysis, 10. pp. 10717-10725. ISSN 2155-5435

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    Abstract

    The mechanism of the reactions between dppf-Ni0 complexes and alkyl halides has been investigated using kinetic and mechanistic experiments and DFT calculations. The active species is [Ni(κ2-dppf)(κ1-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-catalysed Kumada cross-coupling reactions of alkyl halides are shown to be significantly improved by the addition of free dppf ligand.