Electrochemically controlled dearomative 2,3-difunctionalization of indoles to synthesize oxoindoline derivatives

Abstract

A general and practical protocol for electrochemisty-controlled dearomative 2,3-difunctionalization of indoles via electrochemically anode-selective oxidative cross coupling has been demonstrated. The reaction runs under metal, oxidant and catalyst free condition,...

Recent advances in electrochemical synthesis of diversely functionalized oxindole derivatives

“…In 2022, the Feng group developed an electrochemically controlled difunctionalization of indoles under metal-, oxidant-, and catalyst-free conditions, leading to a wide range of synthetically useful oxindoles (Scheme 35). 39 The reactions were performed in an undivided cell equipped with platinum plates as the anode and cathode under a constant voltage mode, and various 3,3-diaryl-2-oxindoles 94 could be obtained in moderate to excellent yields. Remarkably, the reaction product can be tuned to 3-aryl-3-hydroxyl-2-oxindoles 95 by switching the anode material to a graphite plate under the same conditions.…”

Electrochemical oxidation of 3-substituted indoles

“…Chemical oxidants are a well-established tool for this transformation [14][15][16][17][18][19][20][21][22][23][24][25][26][27] (Scheme 1A), but these reagents present safety and downstream pollution issues. A mild and green alternative to harsh chemical oxidants is electrochemical oxidation; [28][29][30] several anodic transformations of indoles have been reported, [31][32][33][34][35][36][37][38][39] but two recent reports describing the electrochemical oxidative rearrangement of tetrahydroβ-carbolines (Scheme 1B) 40,41 prompts disclosure of our own efforts in this area (Scheme 1C).…”