Weak Directing Group Steered Formal Oxidative [2+2+2]-Cyclization for Selective Benzannulation of Indoles

A double C–H activation and double insertion process to achieve the synthesis benzo­[e]­indole frameworks has been disclosed. This type of benzannulation is directed by a trifluoromethylketone moiety, which is easy to install on the indole C3-position. Overall the reaction takes places as an oxidative cyclization of two alkynes with the C4–C5 position of indole.本研究报道了一种通过双重C-H活化（double C–H activation）与双重插入（double insertion）过程合成苯并[e]吲哚骨架（benzo[e]indole frameworks）的方法。该类苯环化反应由三氟甲基酮基团（trifluoromethylketone moiety）导向，该基团易于连接至吲哚C3位。整体而言，该反应以两分子炔烃与吲哚C4-C5位发生氧化环化的形式进行。