Migration of redundant ethynyl substituents along polycyclic aromatic hydrocarbon peripheries. Consequences for polycyclic aromatic hydrocarbon build up

Article abstract of DOI:10.1016/S0040-4039(97)01685-7

The formation of cyclopenta[cd]pyrene (5) and benzo[ghi]fluoranthene (6) upon FVT of 3,9-bisethynylphenanthrene (1) and 8-ethynylfluoranthene (2), respectively, suggests that redundant ethynyl substituents, which cannot give five- and/or six-membered ring formation via ethynyl ethylidene carbene equilibration followed by carbene C-H insertion, can migrate along the PAH periphery at high temperatures.