Synthesis of Hexabenzotriphenylene and Other Strained Polycyclic Aromatic Hydrocarbons by Palladium-Catalyzed Cyclotrimerization of Arynes

To evaluate the potential of the recently developed palladium-catalyzed trimerization of arynes for the synthesis of strained polycyclic hydrocarbons, the trimerizations of 1,2-didehydronaphthalene ( 1 ) and 9,10-didehydrophenanthrene ( 2 ), generated from the corresponding o -trimethylsilylaryl triflates 5 and 11, respectively, were studied. The synthesis of tribenzo[ a, g, o ]triphenylene ( 6 ), tribenzo[ a, g, m ]triphenylene ( 7 ), and hexabenzo[ a, c, g, i, m, o ]triphenylene ( 12 ) is described.