Which side of the 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 opens an epoxide?

Epoxides can also be opened by other anhydrous acids (HX) to form a trans halohydrin. When both the epoxide carbons are either primary or secondary the halogen anion will attack the less substituted carbon and an SN2 like reaction.

Which side of an epoxide is attacked under acidic conditions?

Under acidic conditions, epoxides open in an “SN1 like” fashion with the nucleophile attacking the more substituted end.

What are ring-opening reactions?

A polymerization in which a cyclic monomer yields a monomeric unit which is acyclic or contains fewer cycles than the monomer. Note: If monomer is polycyclic, the opening of a single ring is sufficient to classify the reaction as ring-opening polymerization.

How do you open a cyclopropane ring?

It is well known that cyclopropane rings, activated toward reaction by the existence of geminal electron-withdrawing groups, can be opened by nucleophiles. One such system is ethoxycarbonylcyclopropyltriphenylphosphonium tetrafluoroborate.

What reagent breaks an epoxide?

For example, aqueous acid [often abbreviated “H3O+”] will open an epoxide under MUCH milder conditions than an “ordinary” ether such as diethyl ether, because epoxides have considerable ring strain [about 13 kcal/mol].

Is epoxide basic or acidic?

There are two ways to open epoxides: under acidic conditions or under basic conditions. And the conditions used will affect the products that you get. Under acidic conditions [e.g. if you see H3O(+) or H(+) ] , you protonate the epoxide oxygen.

What are the methods to initiate ring-opening polymerization?

Ring-opening metathesis polymerization The initiation process involves the coordination of the cycloalkene monomer to the metal alkylidene complex, followed by a [2+2] type cycloaddition to form the metallacyclobutane intermediate that cycloreverts to form a new alkylidene species.