The title compound 6 has been synthesized by condensation of 1,2-bis(t
rimethylsilylcyclopentadienyl)-ethane (3) with glyoxal sulfate to the
tricyclic system 4 and following reduction as well as desilylation. Tw
ofold deprotonation of 6 yields the dilithium compound 7, which was tr
ansformed into the pentafulvenophanes 8 and 9.