Cyclopropanes


Cyclopropanes are a family of organic compounds containing the cyclopropyl group. The parent is cyclopropane.

Synthesis and reactions

Most cyclopropanes are not prepared from the parent cyclopropane, which is somewhat inert. Instead, cyclopropyl groups are often prepared by cyclization of 1,3-difunctional alkanes. An example of the former, cyclopropyl cyanide is prepared by the reaction of 4-chlorobutyronitrile with a strong base. Phenylcyclopropane is produced analogously from the 1,3-dibromide.
A second major route to cyclopropanes entails addition of methylene to an alkene, a process called cyclopropanation.
Substituted cyclopropanes undergo the reactions associated with the cyclopropyl ring or the substituents. Vinylcyclopropanes are a special case as they undergo vinylcyclopropane rearrangement.

Simple substituted cyclopropanes

  • Chlorocyclopropane
  • Cyclopropane carboxylic acid
  • Cyclopropyl amine
  • Cyclopropyl cyanide
  • Cyclopropanol
  • Methylenecyclopropane

    Applications and occurrence

Cyclopropane derivatives are numerous. Many biomolecules and pharmaceutical drugs feature the cyclopropane ring. Famous example is aminocyclopropane carboxylic acid, which is the precursor to ethylene, a plant hormone.
The pyrethroids are the basis of many insecticides. Several cyclopropane fatty acids are known.