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[2H]-ones were obtained via a double oxidative annulation.

Total synthesis of marine cyclodepsipeptide calcaripeptide C, isolated from Calcarisporium sp. Strain KF525 is reported. In the present strategy the macrocycle was constructed through ring-closing metathesis reaction which makes the synthesis more convergent.