Draw the more stable chair conformation of cis-1-tert-butyl-4-chlorocyclohexane. By how much is it favored?

Question

TestHub · Accepted Answer

Draw the two possible chair conformations and calculate the strain energy in each :

structure

Conformer I (t-Bu equatorial, Cl axial) : strain = 2 × 1.0 = 2.0 kJ/mol (two 1,3-diaxial Cl↔H interactions).

Conformer II (t-Bu axial, Cl equatorial) : strain = 2 × 11.4 = 22.8 kJ/mol (two 1,3-diaxial t-Bu↔H interactions).

Conformer I, with the large tert-butyl group equatorial, is the more stable conformation; it is favored by 22.8 - 2.0 = 20.8 kJ/mol.

Chemistry - STEREO ISOMERISM Question with Solution | TestHub