| Abstract: | Conformational analysis of (2-hydroxypentyl)diphenylphosphine oxide 1 and its acetate 2 is described. The NMR, X-ray, IR, and molecular mechanics (MM) modeling studies indicated that phosphine oxide 1 favors different conformers in the solid state and in solution and that conformational preferences are strongly influenced by the nature of the hydrogen bonding. Vicinal proton-proton coupling constants and MM modeling solvation studies indicated that there are deviations from perfectly staggered conformers. Conformational analysis based on the twisted staggered conformers for phosphine oxide 1 made marked changes to the estimated conformational populations. For the acetate 2 , NMR spectroscopy established that the position of the conformational equilibrium is strongly dependent on the polarity of the medium. © 1996 John Wiley & Sons, Inc. |
