The Ir^III/Ni^II-metallaphotoredox-catalyzed enantioselective decarboxylative arylation of α-amino acids has been systematically investigated using density functional theory calculations. The combination of oxidative quenching (Ir^III–*Ir^III–Ir^IV–Ir^III) or reductive quenching (Ir^III–*Ir^III–Ir^II–Ir^III) cycle with the nickel catalytic cycle (Ni^II–Ni^I–Ni^III–Ni^II) is possible. The favorable reaction mechanism consists of three major processes: single-electron transfer, oxidative addition, and stepwise outer-sphere reductive elimination. The rate-determining step is the oxidative addition. Unexpectedly, the enantio-determining C–C bond formation occurs via an ion-pair intermediate involved in the stepwise outer-sphere reductive elimination process, which is unusual in the Ir^III/Ni^II-metallaphotoredox catalysis. Furthermore, computational results reveal that the high enantioselectivity of this reaction is mainly dependent on the steric effect of substituents on substrates. This theoretical study provides useful knowledge for deep insights into the activity and selectivity of visible-light-mediated enantioselective metallaphotoredox dual catalysis at the molecular and atomic levels and benefits the development of asymmetric synthesis.

中文翻译：

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IrIII/NiII-金属光氧化还原催化的 α-氨基酸的对映选择性脱羧芳基化：对映​​决定外球还原消除的理论见解

已经使用密度泛函理论计算系统地研究了Ir ^III /Ni ^II -金属光氧化还原催化的 α-氨基酸的对映选择性脱羧芳基化。氧化猝灭 (Ir ^III –*Ir ^III –Ir ^IV –Ir ^III ) 或还原猝灭 (Ir ^III –*Ir ^III –Ir ^II –Ir ^III ) 循环与镍催化循环 (Ni ^II –Ni ^I –Ni)的组合^III -Ni ^II) 是可能的。有利的反应机理包括三个主要过程：单电子转移、氧化加成和逐步外球还原消除。决定速率的步骤是氧化加成。出乎意料的是，决定对映体的 C-C 键的形成是通过参与逐步外球还原消除过程的离子对中间体发生的，这在 Ir ^III /Ni ^{II中是不常见的}-金属光氧化还原催化。此外，计算结果表明该反应的高对映选择性主要取决于取代基对底物的空间效应。该理论研究为深入了解可见光介导的对映选择性金属光氧化还原双催化在分子和原子水平上的活性和选择性提供了有用的知识，并有利于不对称合成的发展。