Bisphosphine‐Ligated Nickel Pre‐catalysts in C(sp2)–N Cross‐Couplings of Aryl Chlorides: A Comparison of Nickel(I) and Nickel(II)

Abstract The influence of ancillary ligand and nickel oxidation state in the nickel‐catalyzed C(sp2)–N cross‐coupling of aryl chlorides is examined by use of experimental and DFT methods for the first time, focusing on (L)NiCl and (L)Ni(o‐tolyl)Cl pre‐catalysts (PAd‐DalPhos, L1; dppf, L2). Whereas Ni(II) pre‐catalysts generally out‐performed Ni(I) species in our study, the viability and in some cases superiority of Ni(I) pre‐catalysts in challenging aminations is established. Computational analyses support the viability of Ni(0)/Ni(II) cycles featuring rate‐limiting C–N reductive elimination, as well as parallel Ni(I)/Ni(III) mechanisms involving rate‐limiting C–Cl oxidative addition. magnified image