title: Structure elucidation of polyene systems with extensive charge delocalization-carbocations from allylic carotenols.
abstract: [structure: see text] The structures of two diastereomeric cations, readily prepared from beta, beta-caroten-4-ol (1) by treatment with trifluoroacetic acid, have been determined by NIR and NMR spectroscopy, resulting in the complete structure elucidation of the most extensively delocalized carbocations so far described. Higher partial charge was observed toward the center of the polyene chain (larger filled red circles). Bond reversion occurs in the central region of the molecule.
authors.affiliation: Department of Chemistry, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway.
authors.forename: Geir
authors.initials: G
authors.lastname: Kildahl-Andersen
authors.forename: Bjart Frode
authors.initials: BF
authors.lastname: Lutnaes
authors.forename: Jostein
authors.initials: J
authors.lastname: Krane
authors.forename: Synnøve
authors.initials: S
authors.lastname: Liaaen-Jensen
mesh_terms: D002338:Carotenoids / Q000737:chemistry*; D002412:Cations; D009682:Magnetic Resonance Spectroscopy; D011090:Polyenes / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods; D013237:Stereoisomerism
chemical_list: D002412:Cations; D011090:Polyenes; D002338:Carotenoids