The title complex (3) is readily generated from 5,6-dibromoacenaphthene with butyllithium and the diamine in ether at −10–0 °C. The reaction of 3 with biacetyl gave cis-1,2,5,6-tetrahydro-1,2-dimethylcyclopent[fg]acenaphthylene-1,2-diol but no trans-isomer, whereas the reaction of pyracenequinone (PYQ) with methylmagne-sium bromide gave both the cis- and trans-dioh. The reactions of 3 with acenaphthenequinone and PYQ also gave cis-diols. On treatment with phenylboronic acid, these cis-diols quantitatively yielded the corresponding cyclic esters. The diols and their derivatives tend to form crystalline molecular compounds with solvent molecules. The stereoselectivity of the cyclic addition between 3 and the acyclic α-diketone can be best explained in terms of five-membered chelate-ring formation in a transition state.

The reaction of the title complex (3) with benzil did not give the 1 : 1 cyclic addition product expected, but gave 5,6-dibenzoylacenaphthene, 5-(1-hydroxy-2-oxo-1,2-diphenylethyl)-6-(2-oxo-1,2-diphenylethoxy)acenaphthene (5), 5-benzoyl-6-(1-hydroxy-2-oxo-1,2-diphenylethyl)acenaphthene, benzoin, and benzilic acid. Compound 5 suggests a new type of oxophilic addition accompanied by a carbophilic addition. The reaction of 3 with 9,10-phenanthrenequinone in a 1 : 1 molar ratio gave both the oxidative homo-coupling product of 3, 1,2,7,8-tetrahydrodicyclopenta[cd : lm]perylene, and the hydroquinone dianion, which was converted into 9,10-diacetoxyphenanthrene on acetolysis. The differences in the reaction modes between 3 and α-diketones can basically be understood in terms of the redox potentials and the steric factors of the α-diketones.

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Tetracyclic compounds with a thiazolidinone or thiazinone ring fused to 1H-naphth[2,3-d]imidazole-4,9-dione were synthesized. Dimethyl 2-(4,9-dioxo-4,9-dihydronaphth[2,3-d]imidazol-2-ylthio)fumarate (3) was obtained by a reaction of 2,3-dihydro-2-thioxo-1H-naphth[2,3-d]imidazole-4,9-dione with dimethyl acetylenedicarboxylate in methanol. A ring-closure reaction of 3 in acetic anhydride was found to give selectively methyl (3,5,10-trioxo-2,3,5,10-tetrahydronaphth[2′,3′ : 4,5]imidazo[2,1-b]thiazol-2-ylidene)acetate, while, the cyclization of 3 in polyphosphoric acid afforded methyl 4,6,11-trioxo-6,11-dihydro-4H-naphth[2′,3′ : 4,5]imidazo[2,1-b]thiazine-2-carboxylate.