thermal reactions of 4,4‘-disubstituted2,2‘-bis(phenylethynyl)biphenyls with 2,3,4,5-tetraphenylcyclopenta-2,4-dienone were carried out under neat conditions and in diphenyl ether at temperatures between 260 and 270 °C to give rise to 9,10,11,12,13,14-hexaphenylcycloocta[l]phenanthrenes as the adducts in 12−23% yields. We traced these results to the intramolecular [2 + 2] thermal cyclization of 2,2‘-b
From six to seven: 2,2′‐Di(arylethynyl)biphenyls undergo a skeletal rearrangement in the presence of a platinum(II) catalyst to afford polycyclic aromatic compounds containing an azulene unit. The reaction involves CC bond cleavage of a benzene ring, which expands into a seven‐memberedring.