Synthesis of 5,6,17,18-Bisdehydrotetrathia[24]annulene[2.2.2.2]. A Strained Planar Annulene Devoid of Peripheral Conjugation
5,6,17,18-Bisdehydrotetrathia[24]annulene[2.2.2.2], synthesized through a sequence of the McMurry coupling of 1,1-dichloro-2,2-di(5-formyl-2-thienyl)ethene and a novel double Fritsch-Buttenberg-Wiechell rearrangement, has a planar X-ray structure with bent triple bonds and short S-S contacts but shows little sign of peripheral conjugation.