Debie [27] reported 95.2% equatorial and 4.8% axial forms (B3LYP/6-
31g(d), in vacuo) with respect to the isopropenyl group. Importantly,
it was argued that the B3LYP functional gives unreliable
energy differences for six-membered rings [36]. We did not find
any axial conformer contributing substantially to the population
mix, i.e. the lowest in energy was 1.9 kcal/mol higher in energy
compared to the highest in energy of the three equatorial
conformers.