Molecular-Iodine-Catalyzed Cyclization of 2‑Alkynylanilines via Iodocyclization–Protodeiodination Sequence

Molecular iodine catalyzes a cyclization of N-aryl-2-alkynylanilines, which proceeds through the iodocyclization of 2-alkynylanilines followed by the protodeiodination of the iodocyclized intermediates at room temperature. Furthermore, the molecular iodine catalysis can be applied to the cascade cyclization of 2-(enynyl)­aniline and to the tandem cyclization–addition reaction of 2-alkynylanilines with α,β-enones.