Direct Observation of Non-Innocent Reactivity of ZnBr2 with Alkyl Halide Complexes of Nickel

Nickel-catalyzed cross-coupling reactions of alkylzinc reagents with alkyl halides (Negishi couplings) are powerful tools in synthetic organic chemistry. These reactions typically provide the coupled alkane with ZnBr2 as the final products. We report here that gener- ated ZnBr2 does not always act innocently but can mediate a halogen abstraction from the nickel alkyl halide complex. Such reactivity warrants consideration in developing mechanisms and catalyst design for these versatile reactions.