KOtBu-Mediated Aerobic Transition-Metal-Free Regioselective kβ-Arylation of Indoles: Synthesis of β-(2/4-Nitroaryl)-indoles

A (KOBu)-Bu-t-mediated intermolecular oxidative C-C coupling of nitroarenes with indoles is presented in DMSO at room temperature in an open flask. By using this mild and economical methodology, syntheses of beta-(2/4-nitroaryl)-indoles with sensitive functionalities such as bromo, iodo, cyano, and nitro were achieved chemo- and regioselectively. Synthesized beta-(2/4-nitroaryl) indoles were transformed into densely functionalized biindoles, indoloindoles, and (4-aminoaryl)-indoles which demonstrate post-transformation utility of the developed methodology.