Synthesis and properties of a bridged phenalenone incorported into bicyclo[3.2.2]nonane skeleton. 6,9-dihydro-6,9-ethenocyclohepta[gh]phenalen-1-one

6,9-Dihydro-6,9-ethenocycloheptagh]phenalen-1-one ($\text{1}$) has been synthesised starting from the Diels-Alder adduct ($\text{6}$) of acepleiadiene ($\text{5}$) and maleic anhydride through 10 steps with reasonable yields. Spectroscopic properties of $\text{1}$ suggestged the intramolecular electron supply from the remote ethylenes to the phenalenone π-systems in the ground-state of this molecule.