peri-Diketones with the ring system of cyclo-octa[de]naphthalene

peri-Diketones of naphthalene having an eight-membered ring are obtained by oxidative cleavage of cyclopent[a]acenaphthylenes prepared from acenaphthylene-1, 2-dione. Cyclo-octa [de] naphthalenes with two periβ-keto ester ketone carbonyl groups exist as mono-enols. The parent 9, 10-dihydrocycloocta[de]naphthalene-7, 11 (8H)-dione is a stable though reactive diketone, reduced to a pinacol with exceptional ease and forming stable adducts with water or methanol.