Ni-catalyzed cross-electrophile coupling reactions have emerged as appealing methods for constructing organic molecules while avoiding using stoichiometric organometallic reagents. A combination of kinetic, spectroscopic, organometallic, and electroanalytical studies reveals that a Ni-catalyzed reductive 1,2-dicarbofunctionalization of alkenes proceeds via a sequential reduction pathway. The reduction of Ni by Zn is the turnover limiting step, with two Ni(II) species as the catalyst resting state. Zinc is only sufficient to reduce (phen)Ni(II) to a Ni(I) species. (Phen)Ni(I)Br activates aryl bromides via bimolecular oxidation addition, whereas alkyl bromides are activated by (phen)Ni(I)Ar through concerted halogen atom abstraction to form radicals. These results answer some long-standing questions in Ni-catalyzed cross-coupling reactions, and could provide insight into achieving selectivity between different electrophiles in future reaction design.

Mechanistic study of Ni-catalyzed reductive 1,2-dicarbofunctionalization of alkenes

ACS Spring Meeting 2021

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