Epoxidation of alkenes to form epoxides

Click the structures and reaction arrows in sequence to view the 3D models and animations respectively

epoxidation mechanism

Peroxy-acids are commonly used epoxidizing agents. They have an extra oxygen atom between the carbonyl group and their acidic hydrogen, and are electrophilic at oxygen. Attack at this position by a nucleophile displaces carboxylate, which is a good leaving group. An example of one such epoxidation reaction is shown below involving ethylene and performic acid. The mechanism is essentially an electrophilic attack, with a proton being transferred from the epoxide oxygen to the carboxylic acid by-product.

Firstly the nucleophilic π bond donates its electrons to the oxygen, breaking the O-O bond to form the new carbonyl bond. The electrons from the old O-H bond make up the second new C-O bond, and the original carbonyl group uses its electrons to pick up the proton. The transition state for the reaction makes the bond-forming and bond-breaking processes much clearer.

V. G. Dryuk, Tetrahedron, 1976, 32, 2855–2866.

A. S. Rao, S. K. Paknikar and J. G. Kirtane, Tetrahedron, 1983, 39, 2323–2367.


How useful was this page?

Click on a star to rate it!

Average rating / 5. Vote count:

No votes so far! Be the first to rate this page.

As you found this page useful...

Follow us on social media!

We are sorry that this page was not useful for you!

Let us improve this page!

Tell us how we can improve this page (in your own language if you prefer)? If you would like a response, please include your email address e.g. [email protected]

Provided by the