The isopropenyl
dihedrals are similar (differences smaller than 4) to the
dominant conformers calculated by Debie: [27] þ132, 142, and 8
for conformer 1,2 and 3, respectively, which were obtained on the
B3LYP/6-31g(d) level of theory in vacuo. For comparison, the axial
conformer at lowest energy is also shown in Table 1. It is 1.9 kcal/
mol higher in free energy compared to the highest in energy
equatorial conformer (conformer 1) calculated at the mpw1pw91/
cc-pvdz; IEF-PCM: chloroform level of theory.