I₂‐Promoted sp³ C−H Oxidation/Annulation Sequences for the Synthesis of Indoloquinolines from 2‐(1H‐indol‐2‐yl)anilines and Aryl Methyl Ketones

Abstract

An iodine/DMSO‐promoted metal‐free approach has been developed for the synthesis of indoloquinolines via a sequential sp3 C‐H oxidation/intramolecular cyclization using 2‐(1H‐indol‐2‐yl)anilines and aryl methyl ketones. A wide range of aryl methyl ketones, including drugs and complex bioactive molecule‐derived substrates were compatible in the present reaction with yields in the range of 30‐96%. This protocol proceeds through sp3 C‐H oxidation of aryl methyl ketones to phenylglyoxals, subsequent imine formation, and cyclization to furnish the indoloquinolines. Further, the reaction is applicable for gram‐scale synthesis and is operationally simple.