Epoxides are ethers, also called oxiranes, in which the oxygen atom is contained in a three membered ring. This highly strained molecule is very reactive. The most commonly encountered reactions of epoxides are those in which the ring is opened by a nucleophile. Such reactions are advantageously performed in DMSO because DMSO is inert to the epoxides and it also provides maximum reactivity for the nucleophile. When the relatively unreactive 1-phenylcyclohexene oxide is heated with potassium hydroxide in aqueous DMSO, the corresponding trans-glycol is obtained in good yield [Berti, G.; Macchia, B.; Macchia, F.,Tetrahedron Lett. 38, 3421-3427 (1965)].
Epoxides are important chiral building blocks in organic synthesis.