title: Construction of a highly distorted benzene ring in a double helicene.
abstract: A P-fused double helicene consisting of a highly distorted benzene ring, with a bending angle of 23°, has been synthesized by a tandem intramolecular phospha-Friedel-Crafts reaction. Despite the distortion and reduced aromaticity, the double helicene shows thermal and chemical stability. These are important features that make these compounds attractive for applications as a new C2-symmetric bisphosphine ligand. The simple strategy proposed in this work can be used to prepare a diverse range of distorted molecules.
authors.affiliation: International Research Center for Elements Science (IRCELS), Institute for Chemical Research (ICR), Kyoto University, Uji, Kyoto 611-0011 (Japan); Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan).
authors.forename: Sigma
authors.initials: S
authors.lastname: Hashimoto
authors.forename: Soichiro
authors.initials: S
authors.lastname: Nakatsuka
authors.forename: Masaharu
authors.initials: M
authors.lastname: Nakamura
authors.forename: Takuji
authors.initials: T
authors.lastname: Hatakeyama
keywords: aromaticity; density functional calculations; helical structures; ligand design; structure elucidation