title: Relative configuration of natural products using NMR chemical shifts.
abstract: We have measured and quantum chemically computed NMR chemical shifts for three monoterpene diastereomers produced by the walkingstick, Anisomorpha buprestoides. By taking into account the Boltzmann distribution of conformers, the combined RMSDs between experimental and calculated (1)H and (13)C NMR shifts were able to determine the correct isomer, especially when only aliphatic nuclei were used. The calculated relative energies and interproton distances were also consistent with chemical isomerization experiments and NOE-based interproton distance calculations. Complementary to the NOE-based method, a comparison between experimental and calculated NMR chemical shifts can provide an efficient method to assign the relative configuration of natural products.
authors.affiliation: Department of Chemistry, Quantum Theory Project, University of Florida, Gainesville, Florida 32611, USA.
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.forename: Aaron T
authors.initials: AT
authors.lastname: Dossey
authors.forename: Spencer S
authors.initials: SS
authors.lastname: Walse
authors.forename: Arthur S
authors.initials: AS
authors.lastname: Edison
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Merz
mesh_terms: D000465:Algorithms; D000818:Animals; D001688:Biological Products / Q000737:chemistry*; D007313:Insecta / Q000737:chemistry*; D007536:Isomerism; D008968:Molecular Conformation; D015394:Molecular Structure; D039821:Monoterpenes / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*
chemical_list: D001688:Biological Products; D039821:Monoterpenes; C540547:anisomorphal; C540548:peruphasmal; C506675:dolichodial