A novel synthetic route to 3-sulfenyl- and 3-selenylindoles by n-Bu4NI-induced electrophilic cyclization

3-Sulfenyl- and 3-selenylindoles are prepared in excellent yields by the palladium/copper-catalyzed crossing coupling of N,N-dialkyl-o-iodoanilines and terminal alkynes, followed by electrophilic cyclization with arylsulfenyl chlorides and arylselenyl chlorides in the presence of a stoichiometric amount of n-Bu(4)NI.