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 PdCl(2), both 3-sulfenylbenzofurans and 3-selenenylbenzofurans were selectively prepared from the cyclization of 2-alkynyanisoles with disulfides or diselenides in moderate to excellent yields.