Dakin oxidation [SEP] named after
Dakin oxidation
The Dakin oxidation (or Dakin reaction) is an organic redox reaction in which an "ortho"- or "para"-hydroxylated phenyl aldehyde (2-hydroxybenzaldehyde or 4-hydroxybenzaldehyde) or ketone reacts with hydrogen peroxide in base to form a benzenediol and a carboxylate. Overall, the carbonyl group is oxidized, and the hydrogen peroxide is reduced.
The Dakin oxidation, which is closely related to the Baeyer-Villiger oxidation, is not to be confused with the Dakin-West reaction, though both are named after Henry Drysdale Dakin.
pH range that favors deprotonated over protonated hydroxyl group.
Variants.
Variants Acid-catalyzed Dakin oxidation.
The Dakin oxidation can occur in mild acidic conditions as well, with a mechanism analogous to the base-catalyzed mechanism. In methanol, hydrogen peroxide, and catalytic sulfuric acid, the carbonyl oxygen is protonated (14), after which hydrogen peroxide adds as a nucleophile to the carbonyl carbon, forming a tetrahedral intermediate (15). Following an intramolecular proton transfer (16,17), the tetrahedral intermediate collapses, [