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-Bu4NI.