Chapter 16: Ethers, Epoxides and Sulfides

Epoxides

Epoxides are just a sub-class of ethers, in that they contain the C-O-C unit.
However, the term "epoxide" is used to describe the 3 membered heterocyclic system.
They are distinguished from other ethers by some their special reactivity.

Nomenclature:
Functional group suffix =  alkene oxide (review)
Functional group prefix = epoxy-

Physical Properties:

• Similar to analogous ethers

• The epoxide unit of a three membered ring containing 2 x C and 1 x O atoms.
• The atoms are bonded to each other via s bonds.
• Both the C-O bonds are polar due to the high electronegativity of the O atom.
• The three membered ring is highly strained (similar to cyclopropane)

• Epoxides are significantly more reactive than simple ethers.
• The small ring system has high ring strain that can be relieved by opening the ring.
• Nucleophiles attack the C of the C-O bond causing the C-O bond to break, resulting in ring opening.

© Dr. Ian Hunt, Department of Chemistry