Dakin-West reaction

The Dakin-West reaction is a chemical reaction that transforms an amino-acid into an amino-ketone using a acid anhydride and a base, typically pyridine. It is named for Henry Drysdale Dakin (1880–1952) and Randolph West (1890–1949). Of special note, the amino-ketone product is always racemic.



With pyridine as a base and solvent, refluxing conditions are required. However, with the addition of 4-dimethylaminopyridine (DMAP) as a catalyst, the reaction can take place at room temperature.

With some acids, this reaction can take place even in the absence of an α-amino group.

This reaction should not be confused with the Dakin reaction.

Reaction mechanism
The reaction mechanism involves the acylation and activation of the acid 1 to the mixed anhydride 3. The amide will serve as a nucleophile for the cyclization forming the azlactone 4. Deprotonation and acylation of the azlactone forms the key carbon-carbon bond. Subsequent ring-opening of 6 and decarboxylation give the final amino-ketone product.