Synthesis of γ , γ ‐Disubstituted γ ‐Butyrolactones via Copper‐Catalyzed Arylation–Lactonization of γ ,δ‐Unsaturated Esters With Diaryliodonium Salts

A Cu‐catalyzed arylation–lactonization process of γ ,δ‐unsaturated esters using diaryliodonium salts as aryl sources is reported. Aryl units having an electron‐donating or electron‐withdrawing group are transferred successfully to the substrates, providing the corresponding γ , γ ‐disubstituted γ ‐butyrolactones under mild conditions with high efficiency. The potential scalability of this method is demonstrated by a successful gram‐scale reaction at a 5.0 mmol scale. This approach offers a practical alternative to existing methods that employ precious metal catalysts or potentially explosive aryl sources.