Chapter 3: Conformations of Alkanes and Cycloalkanes

Summary

The different spatial arrangments that a molecule can adopt due to rotation about the internal σ bonds are called conformations.
Structures that only differ based on these rotations are conformational isomers orconformers.
The study of the energy changes that occur during these rotations is called conformational analysis.

An understanding of the forces at work and the energy associated with these processes is important because the structure of a molecule can have a significant influence on the molecular properties, including dictating the outcome of a reaction. Although the ideas are developed for the simplest functional groups, the alkanes, the same principles can be expanded and applied to other functional groups.

Conformational Language

• Key terms
• Important diagrams (Lewis, line, wedge-dash, sawhorse, Newman, Fischer, Cyclohexane)
  

Basics

• Energetics
• What are conformational isomers ?

• Simple alkanes: Methane, Ethane and Propane
• Higher alkanes: Butane and beyond
• Cycloalkanes : C3 to C5
• C6H12, Cyclohexane
• Substituted cyclohexanes
• Polycyclics
• Heterocycles
• Interesting Molecules
• Sample questions

© Dr. Ian Hunt, Department of Chemistry