Conformational analysis of 14-hydroxymodhephene by NMR, x-ray diffraction and molecular modeling studies

The conformational state of the [3.3.3]propellane framework for 14-hydroxymodhephene was determined by extensive application of one- and two-dimensional H-1 and C-13 NMR spectroscopy combined with x-ray diffraction studies of a synthesized derivative, spectral simulation and molecular modeling. The conformational rigidity of the molecule in solution, established at room temperature, revealed the existence of envelope conformers for both cyclopentane fragments, with C-7 puckered endo and C-10 exo with respect to the mean plane containing the B and C rings. Copyright (C) 2003 John Wiley Sons, Ltd.