Cycloalkanes

What are cycloalkanes?

A single ring of single-bonded carbons to which hydrogens are attached. The formula for cycloalkanes is C$_{n}$H$_{2n}$:

Figure 42.3: Examples cycloalkanes: cyclopropane (left) and cyclopentane (right).

Note: Cycloalkanes can fuse to form bicyclic cycloalkanes.

What stress exists in smaller cycloalkanes?

Ring strain. Ring strain occurs by two mechanisms:

1. Angle strain, which is seen when bond angles depart from the ideal, tetrahedral angle ($\sim$109$^{o}$)
2. Torsional strain, which is seen when bonds are not properly staggered

Cyclohexane has the least strain.