Cobalt Carbonyl-Catalyzed Tandem [2+2+1]/[4+2] Cycloaddition of Dienediyne to New Tetracycles

A tandem reaction of dienediynes catalyzed by dicobalt octacarbonyl gives teracyclic compounds in a poor to high yield depending upon the substrate. The structural frame of the synthesized polycyclic compounds is disclosed for the first time in this study.