Do epoxides react with water?

Epoxides react very efficiently in water with several nucleophiles, and several examples in the literature report that the use of water as reaction medium is essential for realizing processes that cannot be performed alternatively in other reaction media.

What are the reactions of epoxides?

Nucleophiles attack the electrophilic C of the C-O bond causing it to break, resulting in ring opening. Opening the ring relieves the ring strain. The products are typically 2-substituted alcohols. Epoxides can react with a large range of nucleophiles.

What is epoxide hydrolysis?

Epoxide hydrolase is an important enzyme found in many mammalian tissues and catalyzes the hydrolysis of arene oxides and aliphatic epoxides to their corresponding trans-1,2-dihydrodiols (Sipes and Gandolfi, 1986). From: Comprehensive Toxicology (Third Edition), 2018.

Are epoxides soluble in water?

Ring opening of the arene oxide by water gives a trans 1,2-diol by an SN2 mechanism. These diols tend to be water-soluble and easily eliminated from the body. In the case of naphthalene, the epoxide forms at the C-1 to C-2 bond rather than the C-2 to C-3 bond.

Which side of epoxide is attacked?

Attack takes place preferentially from the backside (like in an SN2 reaction) because the carbon-oxygen bond is still to some degree in place, and the oxygen blocks attack from the front side.

What does NaH do in a reaction?

The purpose of NaH [a strong base] is to deprotonate the alcohol (forming H2 in the process), making it into a nucleophilic alkoxide ion, which then performs a substitution reaction [ SN2 mechanism]. Remember – the conjugate base is always a better nucleophile.

What is the simplest epoxide?

ethylene oxide
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.

Which is more soluble in water alcohol or ether?

Alcohol is more soluble than ether mainly because if we look at the alcohol group they can act both as a hydrogen bond donor and acceptor. Because of this property alcohol is able to be more soluble in solvents than ether.

Are epoxides good leaving groups?

Protonation makes the epoxide more electrophilic and creates a better leaving group. Examples of nucleophiles requiring this approach : H2O, ROH etc. The leaving group is the protonated oxygen atom of the epoxide in the form of a neutral alcohol. Typically the nucleophile is then deprotonated to give a neutral product.

What does NaH THF do in a reaction?

We’re breaking C-Br and forming C-O. The purpose of NaH [a strong base] is to deprotonate the alcohol (forming H2 in the process), making it into a nucleophilic alkoxide ion, which then performs a substitution reaction [ SN2 mechanism].

What does THF do in a reaction?

In the laboratory, THF is a popular solvent when its water miscibility is not an issue. It is more basic than diethyl ether and forms stronger complexes with Li+, Mg2+, and boranes. It is a popular solvent for hydroboration reactions and for organometallic compounds such as organolithium and Grignard reagents.

What are cyclic ethers called?

Cyclic ethers can be considered (nonaromatic) heterocyclic compounds. The ethers with three atoms in the ring are indicated as oxiranes, with four as oxetanes, five as tetrahydrofurans, and six as tetrahydropyrans. Oxiranes are also known as epoxides.

How are ring opening reactions of epoxides performed?

The nonenzymatic ring-opening reactions of epoxides provide a nice overview of many of the concepts we have seen already in this chapter. Ring-opening reactions can proceed by either S N 2 or S N 1 mechanisms, depending on the nature of the epoxide and on the reaction conditions.

How is the addition of epoxide affected in acidic conditions?

Under acidic conditions, nucleophilic addition is affected by steric effects, as normally seen for S N 2 reactions, as well as the stability of emerging carbocation (as normally seen for S N 1 reactions). Hydrolysis of an epoxide in presence of an acid catalyst generates the glycol . Polymerization of epoxides gives polyethers.

What happens when epoxide reacts with a macromolecule?

If the epoxide reacts with a biological macromolecule, the result is potentially devastating. The epoxides made from aromatic compounds are called arene oxides. These molecules can undergo four kinds of reactions. With one exception, the reactions give products that do not harm the organism.

How does epoxide react with water and glutathione?

It is not easy to predict whether an epoxide will react with water or glutathione and thus be nontoxic, or whether it will react harmfully with macromolecules. However, it appears that relatively stable epoxides tend to undergo ring opening by water or glutathione.