Synthesis of hexabenzotriphenylene and other strained polycyclic aromatic hydrocarbons by palladium-catalyzed cyclotrimerization of arynes

[GRAPHICS] 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.