MOLECULAR MODELING AND NMR SPECTROSCOPIC EXAMINATION OF (E)-CYCLODEC-5-ENONE AND ITS 2- AND 10-METHYL ANALOGS

The H-1 and C-13 NMR spectra of (E)-cyclodec-5-enone and its 2- and 10-methyl analogs were determined. The H-1 NMR spectrum of the former was determined over the temperature range -60 to 20-degrees-C. Information from the 2-D INADEQUATE spectrum of the parent compound was combined with that derived from the homonuclear and heteronuclear correlation spectra to assign the olefinic proton at C-6. In all three proton spectra, this was the only set of resonances sufficiently well defined to allow conformational information to be deduced. Molecular modeling by molecular mechanics, semi-empirical and ab initio molecular orbital methods were used to predict conformational preferences. These results were then compared with the NMR data.