A Synthetic Route to 2-Alkyl Indoles via Thiophenol-Mediated Ring-Opening of N-Tosylaziridines Followed by Copper Powder-Mediated C-N Cyclization/Aromatization

A simple strategy for the syntheses of 2-alkyl indoles via regioselective ring-opening of 2-(2-haloaryl)-3-alkyl-N-tosylaziridines with thiophenol, followed by copper powder-mediated intramolecular C-N cyclization and subsequent aromatization by the elimination of thiophenol, with good yields is described. Utilizing this protocol, 2-carboxyindole has been synthesized easily.