Electrochemical Oxidation of Indoles to Access Tryptanthrins at Room Temperature

An electrooxidative reconstruction of the indole core under ambient conditions is reported, resulting in the construction of tryptanthrins. This electrochemical strategy simplifies molecular skeleton-hopping by employing commercially available NH-indole feedstock as the starting materials. Furthermore, the synthetic value of this skeletal reconstruction was demonstrated by divergent further transformations. A preliminary mechanistic investigation involving control experiments and cyclovoltammetric studies showed the indispensability of electricity, as well as the importance of oxygen and TEMPO, thereby revealing a possible reaction pathway. image