Baeyer-Villiger oxidation is the oxidation of ketones to carboxylic acid esters using a peroxyacid as the oxidizing agent.

eg. 1:

eg. 2:

Mechanism:

When the two ligands on the carbonyl carbon in the ketone are different, Baeyer-Villiger oxidation is regioselective.  Of the two alpha carbons in the ketone, the one that can stabilize a positive charge more effectively, which is the more highly substituted one, migrates from carbon to oxygen preferentially.

eg. 1:

eg. 2: