Towards the Discovery of a Novel Radical-Proof, Iridium-Based Photocatalyst for Applications in Synergistic Catalysis

Abstract

Photoredox catalysis enables efficient access to broad reactivity under very mild conditions. Synergistic catalysis couples one catalytic mode, ie. photoredox catalysis, with another such as transition metal catalysis or organocatalysis to access greater reaction space. Metallaphotoredox catalysis has been used to achieve and optimize decarboxylative sp2-sp3 bond formation between alkyl carboxylic acids and aryl halides. Of particular interest are iridium(III)-based photocatalysts, due to their high quantum yield and versatility of emission wavelength. While this reaction has been optimized significantly, a current problem exists in which catalytically generated organic radical intermediates deactivate the photocatalyst via the Minisci reaction. By modifying catalyst scaffolds, a catalyst impervious to radical attack could be accessed. Current efforts to synthesize such a catalyst have not been realized; however, future efforts will build upon the knowledge gained thus far in the manipulation of photocatalyst properties.