Neglected Aspects of Anthracenide (Anthracenidyl) Chemistry -Reactions with two N-Benzoylaziridines

Reaction of anthracenide A^- with N-benzoylaziridines 1a,b forms charged radicals 3a,b by single electron transfer and homolytic ring opening. Reactions follow that are known or expected as e.g. coupling with position 9 of A^.- forming dihydroanthracene anions 9a,b that yield amidoethylated dihydroanthracenes 10a,b, or react with 1a,b giving finally 9,10-bis-amidoethylated dihydroanthracenes 11a,b. Results depend on experimental conditions and on the counter ions Na⁺ or Li⁺. Coupling is not regiospecific: contributions by positions 2 and 1 reach 29% or 4%, respectively, of total coupling with the primary radical 3a; much higher contributions are possible with Li. Product 21s (probably 3,3′-disubstituted tetrahydrobianthryl) may arise by hydrogen detachment from the first intermediate (29) of coupling with position 2 and dimerization of the formed 2-substituted A^.- (30). Coupling products may be fully aromatized or may be hydroxylated in one of the benzylic positions. With counter ion Li⁺ a non-SET reaction of 1a with the dimer of A^.- is indicated by the isolation of 9-benzoyl-dihydroanthracene 15 and by 19% yield of 16a (aromatized 10a). Reaction of 3b with anthracene is indicated by 10,10′-disubstituted tetrahydrobianthryl 37.