Cyclization of a 1,8‐Diphenylanthracene by Scholl Reactions to Form Five‐ and Seven‐Membered Ring Embedded Polycyclic Aromatic Hydrocarbons

yielded three cyclized products depending on the equivalent of the oxidant. The singly cyclized product was a benzo[a]fluoranthene derivative, which further cyclized to the doubly cyclized product by formation of a seven-membered ring. Reactions with a large amount of DDQ yielded a deep red product, which was identified as an unexpected triply cyclized product with a rubicene framework formed via the migration of a methyl group in the mesityl group. The molecular structures and aromaticity of these five- and seven-membered ring products were investigated by X-ray analysis and DFT calculations. The optical and electrochemical properties depend on the HOMO-LUMO gap, which decreases as the cyclization proceeds. The rubicene formation is proposed to proceed via an arenium ion intermediate and a 1,2-methyl shift step.