The mechanism of photoredox-mediated iridium(III)/nickel(II)/3-acetoxyquinuclidine triple-catalyzed C(sp³)−C(sp²) cross-coupling includes photocatalytic, nickel, and HAT catalytic cycles. Due to more favorable oxidative addition of C−Br to Ni(I) than HAT to avoid the stable Ni(II) species, the α-carbon centered radical is captured by Ni(III) to form an unusual [Ni^III]^⊖C^⊕ species when the electron-withdrawing group is introduced into HAT catalyst.

中文翻译：

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Photoredox 介导的铱(III)/镍(II)/奎宁环三重催化 C(sp3)−C(sp2) 交叉偶联的理论机理研究

光氧化还原介导的铱(III)/镍(II)/3-乙酰氧基奎宁环三重催化C( sp ³ )−C( sp ² )交叉偶联的机制包括光催化、镍和HAT催化循环。由于 C−Br 对 Ni(I) 的氧化加成比 HAT 更利于避免稳定的 Ni(II) 物种，以 α-碳为中心的自由基被 Ni(III) 捕获，形成不寻常的 [Ni ^III ] ^⊖ C ^⊕当吸电子基团被引入 HAT 催化剂时的物种。