An Expedient Construction of Seven-Membered Rings Adjoining Aromatic Systems

An unusual radical-mediated fusion of a seven-membered ring onto an aromatic system exploits the relatively long lifetime of radicals generated using dithiocarbonates (xanthates). This type of annelation (an example is shown), which was hitherto very difficult to accomplish by more traditional radical methods, was used to construct a variety of complex structures. Y=OAc, CN, (CH2)8OAc, CH2CO2Et, phthaloyl.