Photoredox‐Catalyzed Tandem Demethylation of N,N‐Dimethyl Anilines Followed by Amidation with α‐Keto or Alkynyl Carboxylic Acids

Abstract

AbstractWe report herein, a biomimetic approach for highly selective monodemethylation of N,N‐dimethyl anilines to generate secondary amines and subsequent coupling with α‐ketocarboxylic acids or alkynyl carboxylic acids to form α‐ketoamides or alkynamides respectively under visible light photoredox catalyst in a single operation. From the deuterium‐labeling experiment, it was probed that demethylation is the slowest step in this tandem process. Whereas, control experiments and spectroscopic studies revealed that photoredox catalyst is also involved in the subsequent amidation step. The reaction proceeds smoothly at room temperature providing moderate to excellent yield of the coupling products. The amides have also been converted to a series of biologically active spiro compounds.magnified image