Tandem catalysis, the use of a single catalyst to promote two or more mechanistically distinct cycles in one pot to assemble complex organic molecules, is an attractive target. In this paper, we report a reductant‐triggered tandem palladium catalysis process that rapidly assembles 3,4‐fused tricyclic indoles from three readily available starting materials. This tandem process involves a Pd⁰‐catalyzed in situ coupling/cyclization/Michael addition reaction to install simultaneously two functional groups at the C4 and the C3 positions of indoles. This is followed by a Pd⁰‐catalyzed intramolecular cyclization which builds a seven‐membered C4, C3‐bridge. Sodium formate is used to trigger the necessary switching between the palladium catalysed reactions.

中文翻译：

---

串联钯催化快速构建3,4-熔合三环吲哚

串联催化是一种有吸引力的目标，串联催化是在一个罐中促进两个或多个机械上不同的循环以组装复杂的有机分子。在本文中，我们报告了一种由还原剂触发的串联钯催化方法，该方法可从三种容易获得的起始原料快速组装3,4-稠合的三环吲哚。此串联过程涉及Pd ⁰催化的原位偶联/环化/ Michael加成反应，以在吲哚的C4和C3位置同时安装两个官能团。随后是Pd ⁰催化的分子内环化反应，该反应可构建七元C4，C3桥。甲酸钠用于触发钯催化反应之间的必要转换。