Nickel-catalyzed regioselective C–H bond alkenylation of indoles and related heteroarenes with alkenyl bromides is accomplished under relatively mild conditions. This method allows the straightforward synthesis of C-2 alkenylated indoles employing an air-stable and well-defined nickel catalyst, (bpy)NiBr₂, providing a solution to the limitations associated with hydroindolation and oxidative alkenylation. The reaction conceded the coupling of indole derivatives with various alkenyl bromides, such as aromatic and heteroaromatics, α- and β-substituted as well as exo- and endo-cyclic alkenyl compounds. An extensive mechanistic investigation, including controlled study, reactivity experiments, kinetics and labeling studies, and EPR and XPS analyses, highlights that the alkenylation proceeds through a single-electron transfer process comprising an odd-electron oxidative addition of alkenyl bromide. Furthermore, the alkenylation operates via a probable Ni(I)/Ni(III) pathway involving the rate-limiting C–H nickelation of indole.

中文翻译：

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镍催化的吲哚与烯丙基溴的直通式和区域选择性CH H烯基化：范围和机理

吲哚和相关杂芳烃与烯基溴的镍催化区域选择性C–H键烯基化反应是在相对温和的条件下完成的。该方法允许使用空气稳定且定义明确的镍催化剂（bpy）NiBr _2来直接合成C-2烯基化的吲哚，从而解决了与氢化吲哚化和氧化烯基化有关的局限性。该反应使吲哚衍生物与各种烯基溴化物（如芳族和杂芳族化合物，α-和β-取代的以及exo-和endo）偶联。-环烯基化合物。广泛的机械研究，包括对照研究，反应性实验，动力学和标记研究，以及EPR和XPS分析，突出表明烯基化过程是通过单电子转移过程进行的，该过程包括烯基溴的奇数电子氧化加成。此外，烯基化反应是通过可能的Ni（I）/ Ni（III）途径进行的，该途径涉及吲哚的限速C-H镍化反应。