Question

Need a detailed drawing of the most stable chair conformation for trans-1-isopropyl-3-methylcyclohexane

Answer 1

Explanation:

2 conformational isomers for trans-1-Isopropyl-3-methyl cyclohexane are possible.

1. Trans-1(a)-Isopropyl-3(e)-methyl cyclohexane. This will be less stable conformer as bulky isopropyl group is axial. Total energy of this conformation is 4.2 kcal/mol.
2. Trans-1(e)-Isopropyl-3(a)-methyl cyclohexane. This conformer will be more stable as the relatively bulky isopropyl group is at equatorial position. Energy of this conformation is 1.8 Kcal/mol.

Hence (2) is more stable conformation than (1) by amount (4.2-1.8=) 2.4 Kcal/mol.