Diverting Established Enone Reactivity through Excited-State Umpolung

α,β-unsaturated ketones demonstrate well-understood reactivity profiles in the ground-and excited-states, which has facilitated their deployment for the synthesis of complex organic architectures.Beyond synthetic chemistry, they are also applied directly as therapeutics, in the design of fluorescent probes, as corrosion inhibitors, and as photo-initiators of radical reactions. Until recently, they had not been deployed as substrates in transposition reactions owing to the challenge of overriding these canonical reactivity patterns and applications. However, using only visible light in combination with a fluorophore and a phosphine catalyst, we achieved the step-and atom-efficient positional exchange of the functional groups adorning the olefin motif with excellent yields and scope. This Synpacts article delves into the discovery and development of this unprecedented transformation as well as the mechanistic insights derived from targeted studies.