Chapter 3.15, Problem 19P

Interpretation Introduction

Interpretation:

The most stable conformation of the piperidine derivative is to be drawn. In piperidine derivative the hydrogen bonded to nitrogen has been replaced by methyl.

Concept introduction:

The position of axial and equatorial bonds in cyclohexane chair form is

A substituent at an equatorial position is more stable than a substituent at an axial position.

A methyl group has $\text{1-3-diaxial}$ interactions with the substituents present on the same side of the ring (cis substituents)

The van der Waals strain is greater between the axial hydrogen and the hydrogen of axial methyl group at $\text{C-3}$ and $\text{C-5}$ and negligible between the axial hydrogen at $\text{C-1}$, $\text{C-3}$, and $\text{C-5}$.