Reactions of Perylene with Aryne Intermediates

The Diels-Alder reactions of perylene (diene) with 1,2-didehydrobenzene and 4,5-dimethoxy-1,2-didehydrobenzene (dienophiles) generated in situ by two methods were studied. According to the first method, diazonium salts derived from anthranilic acids and stabilized by 4-dodecylbenzenesulfonic acid were treated with potassium fluoride in toluene in the presence of 18-crown-6 on heating. The second method involved generation of arynes directly from substituted anthranilic acids by the action of isoamyl nitrite in toluene on heating. The corresponding Diels-Alder adducts, naphtho[1,2,3,4-ghi]perylene and 10,11-dimethoxynaphtho-[1,2,3,4-ghi]perylene, were isolated in up to 77% yield. The yield was higher when the aryne intermediate was generated from the stabilized diazonium salts. 4,5-Difluoro-1,2-dehydrobenzene and 2,3-dehydronaphthalene generated by both methods failed to react with perylene.