Question

Which conformation is the most stable for cyclohexane, is it the boat conformation or the chair conformation?

Answer 1

The chair conformation is clearly the most stable conformation.

Explanation:

The chair conformation clearly minimizes the number of transannular interactions. Given the chair form, each face of the ring has 3 axial substituents that sterically interact, versus superposition of 2 hydrogens at each end of the boat.

When the ring is substituted with a butyl group or even a methyl group, the conformational preference for equatorial substitution is even more marked.

How do you rationalize this? Make a model, and consider the transannular interactions yourself.