Palladium-Catalyzed Intermolecular Oxyvinylcyclization of Alkenes with Alkynes: An Approach to 3‑Methylene γ‑Lactones and Tetrahydrofurans

A novel chloropalladation-initiated intermolecular oxyvinylcyclization of alkenes with alkynoic acids or alkynols is developed. This protocol provides a series of 3-methylene γ-lactone and tetrahydrofuran derivatives in moderate to excellent yields with high stereoselectivities in the presence of PdCl2 and CuCl2 or CuCl2·2H2O. Besides a broad substrate scope, this method has the advantages of mild reaction conditions and easily accessible starting materials. Furthermore, the construction of C–Cl, C­(sp2)–C­(sp3), and C–O bonds in one step was also achieved in this transformation.