NHC‐Free Ketone Synthesis via Radical Coupling Mechanisms

Abstract Ketone synthesis via radical coupling mechanisms has recently gained significant attention. Traditionally, these methods have relied on N‐heterocyclic carbenes (NHCs) to generate the key ketyl radical intermediate, either through single‐electron reduction of acyl azolium or single‐electron oxidation involving the Breslow intermediate. In this report, we introduce a novel photoredox protocol that directly generates ketyl radicals from stable acyl imidazoles without the need for NHCs. This approach not only simplifies the process, but also demonstrates broad tolerance for various alkyl radical substrates. Additionally, it can be extended to facilitate relay‐radical coupling reactions.