Dual‐Catalysed Intermolecular Reductive Coupling of Dienes and Ketones**

Abstract

AbstractWe report a mild, catalytic method for the intermolecular reductive coupling of feedstock dienes and styrenes with ketones. Our conditions allow concomitant formation of a cobalt hydride species and single‐electron reduction of ketones. Subsequent selective hydrogen‐atom transfer from the cobalt hydride generates an allylic radical which can selectively couple with the persistent radical‐anion of the ketone. This radical‐radical coupling negates unfavourable steric interactions of ionic pathways and avoids the unstable alkoxy radical of previous radical olefin‐carbonyl couplings, which were limited, as a result, to aldehydes. Applications of this novel and straightforward approach include the efficient synthesis of drug molecules, key intermediates in drug synthesis and site‐selective late‐stage functionalisation.