Research on Synthesis and Properties of Macrocyclic Cross-Conjugated and Tricyclic Compounds

Syntheses and properties of the tricyclic conjugated [14]annuleno[16]annuleno-[14]annulene (1) and the cross-conjugated [13][15]fulvalene (2) have been studied. In the case of (1), the improved synthetic method for 5, 14-dimethyl-1, 3-bisdehyrdo[14]annuleno[c]furan which is the useful material for the preparation of key compound 5, 14-dimethyl-9, 10-bis[2'-(1'-formyl-1'-ethenyl)]-1, 3-bisdehydro-[14]annulene (25), was developed. However, the McMurry reductive coupling of (25) or Witting reaction with the phosphonium salt derived from (25) were unsuccessful. Multi-step synthesis of (2) from the [13]annulenone utilizing repeated Wittig reactions was attempted and afforded the title compound (2). From the examination of ^1H NMR spectra, [13][15]fulvalene (2) proved to show no ring current effect but have polyolefinic character. <<figure>>