Domino Aryne Annulation via a Nucleophilic–Ene Process

1,2-Benzdiyne equivalents
possess the unique property that they
can react with two aryno­philes through iteratively generated
1,2- and 2,3-aryne intermediates. Upon rational modification on the
second leaving group of these aryne precursors, a domino aryne annulation
approach was developed through a nucleophilic–ene reaction
sequence. Various benzo-fused N-heterocyclic frameworks were achievable
under transition metal-free conditions with a broad substrate scope.