KI‐Mediated Chlorine Gas‐Free Synthesis of 3,3‐Dichloro‐2‐oxindole Derivatives

Abstract

An efficient and environmentally friendly methodology for 3,3‐dichlorination and 2‐oxidation of indole derivatives is described. Using KI as promotor, MCl (M=K, Na) as chlorine source, and oxone as oxidant, the reaction proceeds smoothly affording various functionalized 3,3‐dichloro‐2‐oxindoles in moderate to excellent yields. This strategy can also be extended to 3‐substituted indoles. With a broad substrate scope, it is a practical approach to 3,3‐disubstituted‐2‐oxindoles.