N-Heterocyclic Carbene Ligand-Controlled Regioselectivity for Nickel-Catalyzed Hydroarylation of Vinylarenes with Benzothiazoles

A facile regioselective switch for nickel-catalyzed hydroarylation of vinylarenes with benzothiazoles has been developed, which relies on the simple structural variation of novel Ni(II) complexes of the type Ni(NHC)[P(OR)(3)]Br-2. Using magnesium turnings as the reductant, Ni(IMes)[P(OEt)(3)]Br-2 afforded branched products, while Ni(IPr*(OMe))[P(OEt)(3)]Br-2 created steric demand to afford linear products. This work also provides a rare example of the rational design of heteroleptic Ni(II) complexes that display the required air stability, reactivity, and regioselectivity via synergism between NHC and phosphite ligands.