Question #de793

1 Answer
May 22, 2015

The hydrogen ion comes from the peroxyacid that is used as the oxidizing agent.

The Baeyer-Villiger reaction is the oxidation of a ketone to a carboxylic acid ester using a peroxyacid as the oxidizing agent. For example,

Commonly used peroxyacids are peroxyacetic acid, MCPBA , and peroxytrifluoroaceticacid with disodium hydrogen phosphate added as a buffer.


The mechanism is complicated and takes place in several steps.

Step 1

The peroxyacid protonates the oxygen of the carbonyl group.

This makes the carbonyl carbon more electrophilic.

Step 2.

The peroxyacid anion attacks the carbonyl carbon to form a so-called Criegee intermediate.

Step 3.

The Criegee intermediate decomposes. As a carboxylate ion leaves, an alkyl group migrates to the adjacent O atom.

Step 4.

Finally, the carboxylate ion deprotonates the cation to produce the ester and a carboxylic acid.