POLYARYLENES AND POLY(ARYLENEVINYLENE)S .5. SYNTHESIS OF TETRAALKYL-SUBSTITUTED OLIGO(1,4-NAPHTHYLENE)S AND CYCLIZATION TO SOLUBLE OLIGO(PERI-NAPHTHYLENE)S

A homologous series of oligo(1,4-naphthylene)s from the binaphthyl 6 to the sexinaphthylene derivative 10 were synthesized successively. The Pd(0)-catalyzed reaction between aryl bromides and arylboronic acids was used as a coupling method. By appropriate choice of the stoichiometry, the method allowed isolation of the intermediates 20 and 21. Under the influence of potassium in 1,2-dimethoxyethane the 1,4-bridged naphthylenes 6 - 10 were partially cyclized to perylene and terrylene units. This anionic cyclization displayed a high regioselectivity. Complete cyclization to the oligorylenes 3b, 4b and 5b was achieved under the influence of AlCl3 and CuCl2 on the bichromophoric systems 24, 25 and 28. The synthetic sequence allowed substitution by tert-butyl groups, so that the oligorylenes 2b, 3b, 4b and 5b were amenable to spectroscopic investigations. The trends in absorption maxima and fluorescence are discussed.