Heterocycles by Cycloaddition. III. Dihydroisoindolequinone, the Correct Structure of the Proposed Azatetracyclononanedione

Abstract

Abstract Pyrolysis of a cyclopentadienequinone–oxazolone adduct (3) gives a 5,6-dihydro-4,7-isoindolequinone (7) and not an azatetracyclic cage compound (4). The dihydroquinone (7) was dehydrogenated to the corresponding isoindolequinone (9), which was synthesized via alternative routes.