The conformation free energy difference (ΔG°(1E → 1A)) for -4methoxycyclohexanone (1) has been determined in 34 solvents, ranging in polarity from tetramethylsilile to trifluoracetic acid, using weighted average vicinal coupling constants and two pairs of anancomeric model compounds (2–5). The free energy difference in the gas phase has been estimated from the equilibrium in silicone oil (DC 550),