title: Synthesis and structure of macrocyclic bis(hydroxynaphthoic amide)s connected by an achiral or chiral diamine.
abstract: Macrocyclic bis(hydroxynaphthoic amide)s 6, connected by an achiral or chiral diamine, were synthesized by the tandem Claisen rearrangement. CD spectra, X-ray crystallographic analyses, and variable-temperature NMR measurements of the chiral bis(hydroxynaphthoic amide)s revealed that the two hydroxynaphthalene rings in these macrocycles adopt a twisted conformation both in solution and in the crystalline state because of the steric hindrance between the two hydroxynaphthalene rings and that the chirality of the twisted conformation is generated by that of the chiral linker. Theoretical calculations revealed that the chiral linker works effectively to favor energetically one conformer of the diastereomers, although a flipping process was possible and can be observed to occur on the NMR time scale in variable-temperature experiments.
authors.affiliation: Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Yoshida
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Hiratani
authors.forename: Tamako
authors.initials: T
authors.lastname: Ogihara
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Kazushi
authors.initials: K
authors.lastname: Kinbara
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Saigo