Rapid Synthesis of Polycyclic Aromatic Compounds by Iodocyclization of Ynamides

Ynamides are recognized as electron‐rich π‐components and show high reactivity toward electrophiles such as iodonium salts. Here we report the iodocyclization of ene‐ynamides and arene‐ynamides leading to naphthalenes and phenanthrenes. We found these reactions were completed within 3 seconds by using I(coll)2PF6 as an iodonium reagent, and cyclized products were obtained in good to high yields. To the best of our knowledge, this method is the most rapid synthesis known to date of polycyclic aromatic compounds. A three‐second synthesis of naphthalenes and phenanthrenes, small units of polycyclic aromatic compounds, has been achieved by iodocyclization of ynamides. This protocol features mild conditions, an easy‐to‐handle iodonium reagent, a simple operation (mix and stir at room temperature), broad substrate scope, and gram scale preparation.