N-Iodosuccinimide-Promoted Rapid Access to Indeno[1,2-c]pyrroles via [3+2] Annulation of Enamine-alkynes

We have developed a metal-free, N-iodosuccinimide (NIS)-promoted, cascade strategy for the efficient synthesis of biologically important indeno[1,2-c]pyrroles via a [3+2] annulation process of enamine-alkynes. This methodology had shown a very broad scope for diversely functionalized enamines and alkynes. We have also developed a one-pot, multicomponent strategy for the direct synthesis of indeno-pyrroles from diynones via enamine-alkynes. Control experiments supported the involvement of NIS as an electrophilic activator via an ionic mechanism rather than a radical pathway. (Figure presented.).