Iodine-Catalyzed Intramolecular Oxidative Thiolation of Vinylic Carbon-Hydrogen Bonds via Tandem Iodocyclization and Dehydroiodination: Construction of 2-Methylene-3-thiophenones

A metal‐free vinylic carbon‐hydrogen bond thiolation has been developed. Under the catalysis of iodine (10 mol%), the cyclization of α‐alkenoyl ketene dithioacetals afforded a broad range of polyfunctionalized 2‐methylene‐3‐thiophenones in good selectivity with moderate to excellent yields via tandem iodocyclization and dehydroiodination. The synthetic strategy can also be extended to the cyclization of ortho‐methylthiophenyl vinyl ketones leading to 2‐methylene‐3‐benzothiophenones.