Copper-Catalyzed Dehalogenative Cyclization/Sulfonylation of Alkynes: Synthesis of Pyrrolidone-Based Vinyl Sulfones

plays a dual role as a sulfur dioxide surrogate and an electron donor, thereby sustaining the copper catalytic cycle without additional reductants. This reaction exhibits broad compatibility with diverse electrophiles, including alkyl iodides, benzyl bromides, and α-carboxyl alkyl bromides. Mechanistic studies indicate that the transformation involves sequential dehalogenation, intramolecular radical cyclization, sulfur dioxide insertion, and electrophilic trapping in a single operation.