Synthesis of Fused Tetracyclic Compounds via Oxidative Annulation: Access to Copper-Catalyzed Indolo[1,2- a ]quinolines and to Ruthenium-Catalyzed Isoquinolin-1[2 H ]-ones.

A facile double oxidative annulation of (en-3-yn-1-yl)phenylbenzamides was developed allowing us to synthetize fused tetracyclic compounds. Under copper catalysis, the reaction proceeds with high efficiency and leads to new indolo[1,2- a ]quinolines via a decarbonylative double oxidative annulation. On the other hand, under ruthenium catalysis, new isoquinolin-1[2 H ]-ones were obtained via a double oxidative annulation.