Conformational analysis of cis-3, 5-dioxa-bicyclo[5.4.0]undecane and its 4-substituted derivatives by DNMR, molecular modeling, and GIAO/DFT methods

Magn Reson Chem. 2010 Sep;48(9):712-7. doi: 10.1002/mrc.2657.

Abstract

Temperature-dependent (1)H and (13)C-NMR spectra of the title compounds are presented. Coalescence effects are discussed and assigned to dynamic process--the interconversion of bicyclic system. The free energies of activation covered the range 39-52 kJ/mol. The dioxepane ring adopts twist-chair (TC) conformation. GIAO/DFT calculation of isotropic shieldings for the set of low-energy conformations showed that only one conformer is present at 298 K in solution that matched well with experimental data.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bridged Bicyclo Compounds, Heterocyclic / chemistry*
  • Carbon Isotopes
  • Magnetic Resonance Spectroscopy / standards
  • Models, Molecular
  • Molecular Conformation
  • Molecular Dynamics Simulation*
  • Protons
  • Reference Standards
  • Temperature

Substances

  • Bridged Bicyclo Compounds, Heterocyclic
  • Carbon Isotopes
  • Protons