title: One-step synthesis of [16]helicene.
abstract: A single-strand arylene-vinylene precursor containing four phenylene and three naphthylene units linked together with six vinylene spacers undergoes helical folding via sextuple photocyclization to give a [16]helicene core in a single step. The phenylene and naphthylene units are arranged in the precursor such that unfavorable side reactions (anthracene or benzoperylene formation) are avoided, and this is the key to the success of the one-step synthesis of [16]helicene, which is the longest [n]helicene that has been synthesized to date.
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan).
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Mori
authors.affiliation: Department of Material and Biological Chemistry, Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata-shi, Yamagata 990-8560 (Japan). tmurase@sci.kj.yamagata-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Murase
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan). mfujita@appchem.t.u-tokyo.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Fujita
keywords: helical structures; photocyclization; polycyclic aromatic compounds; regioselectivity; π-π interactions