Mechanistic Study of a Switch in the Regioselectivity of Hydroheteroarylation of Styrene Catalyzed by Bimetallic Ni-Al through CH Activation

We previously reported a highly efficient protocol for bimetallic Ni–Al‐catalyzed hydroheteroarylation of styrene with benzimidazole based on CH bond activation. We have now delineated the mechanism of this process, providing a rationale for an observed switch in regioselectivity in the presence of the Lewis acid, AlMe3. The present mechanistic study gives insights for the rational development of catalysts that exhibit required linear/branched selectivity. Lewis acid switches regioselectivity: The mechanism underpinning a highly efficient protocol for bimetallic Ni–Al‐catalyzed hydroheteroarylation of styrene with benzimidazole based on CH bond activation has been unraveled (see scheme). The study gives insights that can be used for the rational development of catalysts that give the required linear/branched selectivity.