Copper-Catalyzed Triyne Cyclization via Vinyl Cations

Herein, we describe an efficient copper-catalyzed cyclization of triynes via vinyl cation intermediates. The reaction leads to the practical and atom-economical synthesis of valuable polycyclic pyrroles by constructing three new rings in one step under mild reaction conditions. The proposed reaction mechanism shows the ordered and regioselective reaction of alkynes. Moreover, the possibility of such an asymmetric triyne cyclization also emerges.