Iron-Facilitated Iodine-Mediated Electrophilic Annulation of N,N-Dimethyl-2-alkynylanilines with Disulfides or Diselenides

An efficient synthesis of N-methyl-3-chalcogeno-indoles has been developed via iodine-mediated electrophilic annulation reactions of 2-alkynylaniline derivatives with disulfides or diselenides. In the presence of iodine and iron, a variety of 2-alkynylanilines selectively underwent the electrophilic annulation with numerous disulfides or diselenides leading to the corresponding 3-sulfenylindoles and 3-selenenylindoles in moderate to excellent yields. It is noteworthy that iron can promote the reaction.