[C6H6]n hydrocarbons. Tetracyclic C12H12 compounds from C18H18 precursors

Photochemical rearrangement of the polycyclic homotropylidene carbonate (4) yieds the heptacyclic carbonates (5), (6), and (8), from which the tetracyclo[4,4,2,02,5,07,10]dodecatrienes (1)–-(3) are synthesized.