Concise synthesis of halogenated chrysenes ([4]phenacenes) that favor pi-stack packing in single crystals.

A concise synthesis of halogenated chrysene derivatives from 2,2,2-trifluoroethyl tosylate and halostyrene was established. Friedel-Crafts type cyclization of a 1,1-difluoro-1-alkene bearing halogenated phenyl moieties involved skeletal rearrangement and dehydrogenation to afford the title compound in good to moderate yield. X-ray analysis revealed that the halogen substituents induce pi-stack packing of the molecules in the crystals.