SO2ClF‐Promoted Chlorooxidation of Tryptamine Derivatives: Synthesis of 3,3‐Disubstituted Oxindoles

A series of tryptamine derivatives were transformed into their corresponding 3‐chloro‐2‐oxidation products under simple and mild conditions. This protocol is an operationally simple system that utilizes a single reagent SO2ClF plays a dual role as both oxidant and chloride source and enables the construction of various 3,3‐disubstituted oxindoles with good functional group tolerance. The transformations of the product highlight its potential synthetic applications. An operationally simple system that utilizes a single reagent SO2ClF as both oxidant and chloride source for constructing various 3,3‐disubstituted oxindoles from tryptamine derivatives and other 3‐substituted indoles was reported. The method features operationally simple and mild reaction conditions. The gram‐scale reaction and further transformations of the resulting product were also implemented.