Question

Given cyclohexane in a chair conformation, substitute two of the H labels with bromine and chlorine to construct the more stable conformation of cis-1-bromo-3-chlorocyclohexane. Use the numbering provided on the ring.

Answer 1

Concepts and reason

Cyclohexane is more stable in its chair conformation. In chair conformation of cyclohexane, two types of groups are present at each carbon atom. They are axial groups and equatorial groups. In order to get the more stable chair conformation, bulky groups should be present at equatorial positions.

Fundamentals

If two substituents are cis to each other then they are in up, up (or) down, down to each other in chair conformation.

Bulky groups present in equatorial positions will make the chair conformation most stable. If the bulky groups present in axial positions, then 1,3-diaxial interactions will make the chair conformation less stable.

The given chair conformation is,

The possible chair conformations for the given cis-1-bromo-3-chlorocyclohexane are,

The more stable chair conformation of cis-1-bromo-3-chlorocyclohexane is I.

Ans:

Thus, the more stable chair conformation of cis-1-bromo-3-chlorocyclohexane is,