What is the energy difference between the two chair conformations of the following compound that is due to steric strain? cis-1-bromo-4-isopropylcyclohexane
Assume the following 1,3-diaxial strains.
Br: 1.0 kJ/mol
CH(CH₃) ₂: 4.6 kJ/mol

Question

Quizplus · Accepted Answer

The energy difference between the two chair conformations of cis-1-bromo-4-isopropylcyclohexane is due to steric strain between the bromine and isopropyl groups. The bromine group is larger than the hydrogen atom it replaces, and the isopropyl group is larger than the methyl group it replaces. This causes the bromine and isopropyl groups to be closer together in the cis conformation than in the trans conformation, resulting in more steric strain. The energy difference between the two conformations is 7.2 kJ/mol, which is the sum of the 1,3-diaxial strains between the bromine and isopropyl groups.

What Is the Energy Difference Between the Two Chair Conformations