SYNTHESIS, REACTIONS AND THERMAL-PROPERTIES OF ,11-DIETHENO-5,5A,6,11,11A,12-HEXAHYDRONAPHTHACENE

The title compound 6 was synthesized in nine steps, starting from the Diels-Alder adduct 21 of ketomethanoethanonaphthalene 20 and p-benzoqu inone, via 7,8-dimethylidene-diethenoanthracene 10 followed by Diets-A lder reaction with (E)-bis(phenylsulfonyl)ethylene and aromatization. Photocyclization of 6 led to 32 via an intramolecular [2+2] cycloaddit ion. Hydrogenation and epoxidation of 6 gave the corresponding bis-ben zo hydrocarbon 33 and bis-epoxide 34. Bromination of 6 proceeded by tr ansannular reaction to produce N-type exo, endo dibromide 35b and U-ty pe exo, exo dibromide 36b. Compound 6 underwent thermal decomposition at 210 +/- 5 degrees C to form naphthalene and benzobarrelene.