Force field calculations on some t‐butyl substituted cyclohexane compounds

The results are reported of empirical force field calculations on conformers of t‐butylcyclohexane, cis‐ and trans‐1,4‐di‐t‐butylcyclohexane and trans‐1,2‐di‐t‐butylcyclohexane using the force fields of Allinger et al. (AFF) and of Schleyer et al. (SFF). Comparisons of energy differences and geometric data with experimental values show that both force fields yield useful results; SFF gives the better correlation. The A value of the t‐butyl group is calculated to be 4.7 kcal mol−1 (19.7 kJ mol−1). Cis‐1,4‐di‐t‐butylcyclohexane and trans‐1,2‐di‐t‐butylcyclohexane are predicted to exist as conformational mixtures. The concept of additivity in the prediction of strain energies is discussed.