Photoredox/Copper Dual‐Catalyzed Formal α‐Nucleophilic Addition to α,β‐Unsaturated Enones for the Synthesis of Chiral γ‐Lactones

Comprehensive Summary The inherent polarity mismatch suggests that direct α‐nucleophilic addition is disfavored both thermodynamically and kinetically under conventional conditions. However, indirect α‐nucleophilic addition reactions of α,β‐unsaturated carbonyl compounds via copper‐catalyzed radical pathways have been well established. Herein, we reported a formal asymmetric α‐nucleophilic addition reaction of α,β‐unsaturated carbonyl compounds through merging photoredox catalysis with copper catalysis. This transformation proceeds via radical addition to an α,β‐unsaturated carbonyl compound, followed by a C–O bond cross‐coupling reaction to afford the corresponding chiral γ‐lactones. With this strategy, a diverse range of chiral γ‐lactones bearing a quaternary stereocenter could be afforded.