How are epoxides formed?

Aside from ethylene oxide, most epoxides are generated by treating alkenes with peroxide-containing reagents, which donate a single oxygen atom. Depending on the mechanism of the reaction and the geometry of the alkene starting material, cis and/or trans epoxide diastereomers may be formed.

Are epoxides stable?

Epoxides are stable because, first and foremost, they are ethers. Ethers are an exceptionally unreactive functional group.

What are the two methods of synthesizing epoxides?

There’s two important ways to make epoxides from alkenes, one “direct” and one “indirect”.

Why are epoxides so reactive?

Epoxides are much more reactive than simple ethers due to ring strain. Nucleophiles attack the electrophilic C of the C-O bond causing it to break, resulting in ring opening. Epoxides can react with a large range of nucleophiles.

How do epoxide reactions work?

The Stereochemistry of Epoxide Reactions Both strong and weak nucleophiles open the epoxide ring by an opposite-side nucleophilic attack. This puts the nucleophile and the alkoxy group of opposite sides and as a result, trans or anti-products are always formed.

What are epoxide reactions used for?

Epoxides can be used to assemble polymers known as epoxies, which are excellent adhesives and useful surface coatings. The most common epoxy resin is formed from the reaction of epichlorohydrin with bisphenol A.

What does epoxide mean?

epoxide in American English (eˈpɑksaid, ɪˈpɑk-) noun. Chemistry. an organic chemical that contains a group consisting of an oxygen atom bound to two already connected atoms, usually carbon (epoxy group)

What is an epoxide group?

epoxide, cyclic ether with a three-membered ring. The basic structure of an epoxide contains an oxygen atom attached to two adjacent carbon atoms of a hydrocarbon. Epoxides are easily opened, under acidic or basic conditions, to give a variety of products with useful functional groups.

Which epoxide is more stable?

The epoxide metabolites of alkenes tend to be more stable than arene oxides. They undergo a ring opening with water to give diols. One example of this type of reaction is the ring opening of the epoxide of the anticonvulsant drug carbamazepine.

Is epoxide a racemic?

The racemic epoxide is designated (2R*,3R*)-3-ethyl-2-methyloxirane. When (Z)-2-pentene undergoes the chlorohydrin reaction, there are likewise two possible racemic chlorohydrins formed, which upon base treatment, lead to a single, racemic epoxide. The formation of epoxides by the halohydrin route is stereospecific.

What are epoxides discuss the methods of preparation with mechanism from Halohydrins?

Epoxides by Cyclization of Halohydrins Another approach for preparing epoxides is the intramolecular SN2 reaction of halohydrins upon treatment with a strong base. This is an intramolecular SN2 reaction, and the OH and Br must be in trans configuration in order to accomplish the proper orbital alignment.

Where is epoxide found?

the liver
Epoxides are produced in cells as oxidation products of alkenes and aromatic compounds. These epoxides are formed in the liver by cytochrome P450, and they undergo ring-opening reactions with different substances.

Why are most epoxides toxic?

Most epoxides are toxic because their high reactivity makes them mutagenic. The 3-membered epoxide ring is highly strained, so it is susceptible to ring opening by nucleophiles. Common nucleophiles are NH2,OH- and S-, and there are many of these groups in biological systems.

What happens when an epoxide reacts with a strong base?

Reaction with a strong base then leads to intra-molecular SN2 reaction that produces the epoxide. Reaction of epoxoides with any strong nucleophile leads to ring opening and formation of an alcohol via an inter-molecular SN2 reaction.

What is the structure of epoxide?

Epoxides (also known as oxiranes) are three-membered ring structures in which one of the vertices is an oxygen and the other two are carbons. The most important and simplest epoxide is ethylene oxide which is prepared on an industrial scale by catalytic oxidation of ethylene by air.

How do you prepare an epoxide from a compound?

Preparation of epoxides require a double bond across which the oxygen will be added across the C-C bond to form the oxirane ring. Formation of an oxirane ring can be accomplished in 3 ways starting with an alkene reactant. The use of the following peroxides is a common way to prepare an epoxide.