Ag-Catalyzed Oxidative Cyclization Reaction of 1,6-Enynes and Sodium Sulfinate: Access to Sulfonylated Benzofurans.

A convenient protocol for the synthesis of sulfonylated benzofurans via Ag-catalyzed oxidative cyclization has been established. Chemically stable and easily available sodium sulfinates were used as the sulfonylation reagents and building block for the heterocycle construction. With this novel strategy, various benzofurans bearing dual functional groups could be obtained in good yields with high chemo- and regioselectivities under mild conditions.