title: An attempt to determine the absolute configuration of two ascolactone stereoisomers with time-dependent density functional theory.
abstract: Two stereoisomers of ascolactone (A, B), natural products with two asymmetric carbon atoms, are isolated from the marine-derived fungus Ascochyta salicorniae. Although these compounds show virtually opposite CD spectra and [alpha]D, 1H- and 13C-NMR data exclude the presence of enantiomers and suggest ascolactone A and B to be epimeric lactones. By comparing the experimental CD spectra with those calculated employing time-dependent density functional theory (TDDFT), we elucidate the configuration at one of the asymmetric carbon atoms.
authors.affiliation: Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany.
authors.forename: Simon F
authors.initials: SF
authors.lastname: Seibert
authors.forename: Gabriele M
authors.initials: GM
authors.lastname: König
authors.forename: Elena
authors.initials: E
authors.lastname: Voloshina
authors.forename: Gerhard
authors.initials: G
authors.lastname: Raabe
authors.forename: Jörg
authors.initials: J
authors.lastname: Fleischhauer
mesh_terms: D002942:Circular Dichroism; D007783:Lactones / Q000737:chemistry*; D008956:Models, Chemical; D008968:Molecular Conformation; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D007783:Lactones