Palladium-catalyzed formation of aceanthrylenes: a simple method for peri-cyclopentenelation of aromatic compounds.

Many efforts have been directed toward the synthesis of polynuclear aromatic hydrocarbons (PAH) that have peri-fused fiveand six-membered-ring carbon fragments corresponding to portions of the fullerene surface.1 These include polycyclic aromatic systems with potentially interesting fullerene-like photophysical properties such as acenaphthalene (I), pyracylene (II), aceanthrylene (III), and several cyclopentapyrenes (e.g., IV and V). Previously reported syntheses to construct the two carbon etheno bridges highlighted in the examples involve multistep processes2 or flash vacuum pyrolysis (FVP);3 the latter often results in relatively low yields. In this communication, we report a novel transformation that may ultimately lead to the facile synthesis of these PAH’s.