Inter- and intramolecular addition/cyclizations of sulfonamide anions with alkynyliodonium triflates. Synthesis of dihydropyrrole, pyrrole, indole, and tosylenamide heterocycles

The synthesis of dihydropyrroles, pyrroles, and indoles through [3-atom $ 2-atom] combination of ethyl or aryl tosylamide anions with phenyl(propynyl)iodonium triflate, and the base-mediated intramolecular bicyclization of alkynyliodonium-bearing tosylamide or tosylimide substrates to furnish bicyclic and tricyclic tosylenamide (-enimide) products, is described. A detailed discussion of the scope, limitations, byproduct formation, and the basis for observed diastereoselectivity is presented.