Synthesis of chromeno[2,3-d]imidazol-9(1H)-ones via tandem reactions of 3-iodochromones with amidines involving copper-catalyzed C-H functionalization and C-O bond formation.

A novel six-membered heterocyclic skeleton of imidazochromone was prepared via an efficient one-pot reaction including a key step of copper-catalyzed aerobic C-H intramolecular cycloetherification. Notably, this process does not require the presence of strong para electron-withdrawing groups on the phenol component. Also, the results of this effort show that acyl phenols containing electron-rich heterocycles participate in an efficient C-H activation/C-O formation process.