Biphenylenes. Part 33. Synthesis of bisbenzo[3,4]cyclobuta[1,2-b; 1′,2′-h]- and bisbenzo[3,4]cyclobuta[1,2-c; 1′,2′-g]-phenanthrene, and attempts to prepare planar derivatives of cyclo-octatetraene

Abstract

The title compounds have been synthesized but neither the second of them nor 1,1′-bisbiphenylenyl could be dehydrocyclised to give biphenyleno-annelated derivatives of cycle-octatetraene. 2-Styrylbiphenylene undergoes photodimerisation and not cyclisation. Lithiation of 2-hydroxymethyl-biphenylene gives the 1-lithio derivative from which a series of 1,2-disubstituted biphenylenes has been made. The ¹H n.m.r. spectra of 1,1′-bisbiphenylenyl and its 2,2′-diformyl derivative, also of bisbenzo[3,4]cyclobuta[1,2-c; 1′,2-g]phenanthrene are discussed.