11.9: Structure and Nomenclature of Epoxides
Cyclic ethers are heterocyclic compounds with an oxygen atom in the ring along with carbon atoms. They are named depending on the number of carbon atoms present in their ring system. Cyclic ethers with a three-membered ring system are called “oxirane”, four-membered ring systems as “oxetane”, five-membered ring systems as “oxolane”, and six-membered ring systems as “oxane”. The cyclic structure of these rings imposes angle strain, and this strain is more in the ring having a smaller number of carbon atoms. For instance, a three-membered ring system is more strained than other ring systems with a higher number of carbon atoms.
Epoxides, or oxiranes, are cyclic ethers consisting of a three-membered ring system with two carbon atoms and one oxygen atom. Due to the highly strained structure, oxiranes are more reactive than other ethers.
Generally, the common names of epoxides are derived by adding the suffix “oxide” following the name of the parent alkene. In contrast, the IUPAC names of epoxides mainly designate them as oxirane derivatives where the oxirane ring is the parent structure. However, if the epoxide is considered as a part of any other hydrocarbon system, the prefix “epoxy” is added before the parent alkane name.