Cyclopropane is the smallest alicyclic compound.

An alicyclic compound is an organic compound that is both aliphatic and cyclic. They contain one or more all-carbon rings which may be either saturated or unsaturated, but do not have aromatic character.^[1] Alicyclic compounds may or may not have aliphatic side chains attached.

Simple alicyclic compounds are the cycloalkanes - cyclopropane, cyclobutane, and cyclohexane. A polycyclic cycloalkane is decalin. Bicyclic alkanes are norbornene and norbornadiene. Spiro compounds have bicyclic connected through one carbon atom.

The mode of ring-closing in the formation of many alicyclic compounds can be predicted by Baldwin's rules.

An exocyclic group is always placed outside the ring structure, take for instance the exocyclic double bond on the left:

See for an example isotoluene.

[edit] Cycloalkenes

Cyclohexene is an alicyclic compound with a double bond.

Monocyclic cycloalkenes are cyclobutene, cyclopropene and cyclohexene.

The placement of double bonds in many alicyclic compounds can be predicted with Bredt's rule.

[edit] References

1. ^ International Union of Pure and Applied Chemistry (1995). "Alicyclic compounds". Compendium of Chemical Terminology Internet edition.