Cross-coupling transformations are a powerful tool in organic synthesis. It is known that this kind of transformation undergoes 2-electron redox processes, and, for this reason, silver has been nearly forgotten as catalyst for cross-couplings because silver is mainly considered as a 1-electron redox metal. Herein, we disclose effective Ag(I)-catalyzed cross-coupling transformations using bidentate aminoquinoline as a directing group toward different nucleophiles to form C–C, C–N, and C–O bonds. DFT calculations indicate the feasible oxidative addition of L₁-I substrate via the Ag(I)/Ag(III) catalytic cycle. Furthermore, ion spectroscopy experiments suggest a highly reactive aryl-Ag(III) that in the absence of nucleophiles reacts to form an intermolecular cyclic product [5d-Ag(I)-CH₃CN], which in solution forms 5a. This work proves that silver can undergo 2-electron redox processes in cross-coupling reactions like Pd and Cu.

中文翻译：

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银（I）催化的CX，CC，CN和C-O交叉偶联，使用氨基喹啉直接基团通过难以捉摸的芳基-Ag（III）物种进行

交叉耦合转换是有机合成中的强大工具。众所周知，这种转变经历了2-电子氧化还原过程，并且由于这个原因，因为银主要被认为是1-电子氧化还原金属，所以几乎已经忘记了银作为交叉偶联的催化剂。在这里，我们公开了有效的Ag（I）催化的交叉偶联转化，使用双齿氨基喹啉作为指向不同亲核试剂的直链基团，形成C–C，C–N和C–O键。DFT计算表明通过Ag（I）/ Ag（III）催化循环可实现L ₁ -I底物的氧化加成。此外，离子光谱实验表明，在没有亲核试剂的情况下，高反应性的芳基-Ag（III）会反应形成分子间环状产物[5d-Ag（I）-CH ₃ CN]，其在溶液中形成5a。这项工作证明银可以在Pd和Cu等交叉偶联反应中经历2-电子氧化还原过程。