PdCl2-Promoted Electrophilic Annulation of 2-Alkynylphenol Derivatives with Disulfides or Diselenides in the Presence of Iodine

An efficient synthesis of 3-chalcogen-benzo[b]furans via palladium-promoted annulation reactions of 2-alkynylphenol derivatives with disulfides or diselenides and iodide has been developed. In the presence of I-2 and PdCl2, both 3-sulfenylbenzofurans and 3-selenenylbenzofurans were selectively prepared from the cyclization of 2-alkynyanisoles with disulfides or diselenides in moderate to excellent yields.