A-Level Mechanisms – Reaction of carbonyl compounds with HCN

Nucleophilic Addition

Reaction of carbonyl compounds with HCN to make hydroxynitriles

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


The cyanide functional group will add to a carbonyl as a nucleophile giving a hydroxynitrile (product). HCN is highly toxic, so the reactant is formed by adding dilute acid to sodium cyanide. This MUST be done in a fume cupboard. In the second step the oxyanion (intermediate) accepts a proton.

The product is optically inactive as cyanide can attack from either side (in equal probability).

This reaction is synthetically useful as addition of acid can result in formation of a carboxylic acid. Catalytic hydrogenation reduced that cyanide group to an amine group. The reaction scheme for this is as follows:


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