Mechanistic investigation of the C(sp3)–C(sp3) coupling reaction through synergistic activation of C–H/C–Br bonds by Ir/Ni catalysts

Abstract

In the theoretical calculation study on constructing C(sp³)–C(sp³) bonds via Ir/Ni bimetallic synergistic catalysis, we first investigated the activation of the α-C–H bond of terminal alkenes using the hydrogen atom transfer (HAT) mechanism. This process generates an allyl radical intermediate, which subsequently undergoes radical capture to achieve carbon–carbon double bond migration. Secondly, the sp³-C alkyl fragment was obtained through halogenated hydrocarbon C–Br bond activation, facilitated by Ni-catalyzed cross-coupling reactions between two sp³-C fragments to form the C(sp³)–C(sp³) bond. Additionally, the excitation/quenching behavior of the photoredox catalyst was analyzed, confirming the reduction quenching mode of [Ir^III]*. The energy levels of the photoredox catalyst influence the Z/E selectivity of the product. Specifically, the high-energy Ir complex can isomerize the E-configured product into the Z configuration.