title: Thiophene-fused ladder boroles with high antiaromaticity.
abstract: A series of polycyclic thiophene-fused boroles were synthesized on the basis of stepwise substitution reactions from thienylboronic ester precursors. In these ladder-type π-conjugated systems, the thiophene-fused structure enhances the antiaromaticity of the borole ring. This trend is opposite to the conventional understanding that the arene-fused structure decreases the antiaromaticity of the 4π-electron ring skeletons. The ladder boroles exhibited characteristic properties such as long-wavelength absorptions and low reduction potentials.
authors.affiliation: Department of Chemistry, Graduate School of Science, Nagoya University and JST-CREST, Furo, Chikusa, Nagoya 464-8602, Japan.
authors.forename: Azusa
authors.initials: A
authors.lastname: Iida
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Yamaguchi