NMR spectroscopic conformational analysis of 4‐methylene‐cyclohexyl pivalate—The effect of sp² hybridization

Abstract

The conformational equilibrium of the axial/equatorial conformers of 4-methylene-cyclohexyl pivalate is studied by dynamic NMR spectroscopy in a methylene chloride/freon mixture. At 153 K, the ring interconversion gets slow on the nuclear magnetic resonance timescale, the conformational equilibrium (-ΔG°) can be examined, and the barrier to ring interconversion (ΔG ) can be determined. The structural influence of sp hybridization on both ΔG° and ΔG of the cyclohexyl moiety can be quantified.