Engaging Tertiary Benzylic Radicals in Metallaphotoredox Catalysis: A Modular Approach to Access Diaryl Quaternary Centers

Abstract Herein we report the decarboxylative cross‐coupling of tertiary benzylic carboxylic acids and aryl bromides to furnish all‐carbon diaryl quaternary centers. For the first time, tertiary benzylic radicals are introduced as viable participants in metallaphotoredox‐catalyzed cross‐couplings by suppressing undesired benzylic radical dimerization via fast radical trapping with Cu. We demonstrate the functionalization of feedstock carboxylic acids as well as late‐stage functionalization of carboxylic acid‐containing drugs.