Stoichiometric and Catalytic Aryl−Cl Activation and Borylation using NHC‐stabilized Nickel(0) Complexes

NHC‐nickel (NHC= N ‐heterocyclic carbene) complexes are efficient catalysts for the C−Cl bond borylation of aryl chlorides using NaOAc as a base and B 2 pin 2 (pin=pinacolato) as the boron source. The catalysts [Ni 2 (ICy) 4 (μ‐(η 2 :η 2 )‐COD)] ( 1 , ICy=1,3‐dicyclohexylimidazolin‐2‐ylidene; COD=1,5‐cyclooctadiene), [Ni(ICy) 2 (η 2 ‐C 2 H 4 )] ( 2 ), and [Ni(ICy) 2 (η 2 ‐COE)] ( 3 , COE=cyclooctene) compare well with other nickel catalysts reported previously for aryl‐chloride borylation with the advantage that no further ligands had to be added to the reaction. Borylation also proceeded with B 2 neop 2 (neop=neopentylglycolato) as the boron source. Stoichiometric oxidative addition of different aryl chlorides to complex 1 was highly selective affording trans ‐[Ni(ICy) 2 (Cl)(Ar)] (Ar=4‐(F 3 C)C 6 H 4 , 11 ; 4‐(MeO)C 6 H 4 , 12 ; C 6 H 5 , 13 ; 3,5‐F 2 C 6 H 3 , 14 ).