Synthesis of Naphthalenoferrocenophanes

Several naphthalenoferrocenophanes, in which the two cyclopentadienyl rings are linked by two naphthalene rings, were synthesized via intramolecular reductive coupling of the corresponding formyl compounds with a low valent titanium reagent. Their structures are deduced from IR, NMR, and UV spectra. Transannular π-electronic interaction between the two naphthalene rings is discussed on the basis of electronic spectra.