title: Inducing axial chirality in a "Geländer" oligomer by length mismatch of the oligomer strands.
abstract: Helical molecules are not only esthetically appealing due to their structural beauty, they also display unique physical properties as a result of their chirality. We describe herein a new approach to "Geländer" oligomers by interlinking two oligomer strands of different length. To compensate for the dimensional mismatch, the longer oligo(benzyl ether) oligomer wraps around the oligophenyl backbone. The new "Geländer" oligomer 1 was assembled in a sequence of functional-group transformations and cross-coupling steps followed by final cyclizations based on nucleophilic substitution reactions, and was fully characterized, including X-ray diffraction analysis. The isolation of pure enantiomers enabled the racemization process to be studied by circular dichroism spectroscopy.
authors.affiliation: Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel (Switzerland).
authors.forename: Michel
authors.initials: M
authors.lastname: Rickhaus
authors.forename: Linda Maria
authors.initials: LM
authors.lastname: Bannwart
authors.forename: Markus
authors.initials: M
authors.lastname: Neuburger
authors.forename: Heiko
authors.initials: H
authors.lastname: Gsellinger
authors.forename: Kaspar
authors.initials: K
authors.lastname: Zimmermann
authors.forename: Daniel
authors.initials: D
authors.lastname: Häussinger
authors.forename: Marcel
authors.initials: M
authors.lastname: Mayor
mesh_terms: D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D008968:Molecular Conformation; D009841:Oligonucleotides / Q000737:chemistry; D011083:Polycyclic Compounds / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D009841:Oligonucleotides; D011083:Polycyclic Compounds; D011108:Polymers; C031660:helicenes
keywords: Geländer oligomers; atropisomerism; helical structures; hexaphenyls; racemization