Configurational and conformational analysis Axial-axial and axial-equatorial coupling constants in six-membered ring compounds

Axial-axial and axial-equatorial coupling constants (J_aa and J_ae) have been obtained directly from the NMR spectra of simple AB systems in a number of cis- and trans-l-(substituted)-2-arylcyclohexanes-3,3,6,6-d₄ measured in several solvents. Variations in J_aa and J_ae have been observed with various substituents. No simple correlation is found between electronegativity of substituents and substituent effects on coupling constants. A review of J_aa and J_ae in six-membered ring compounds is given.