Dakin reaction

Dakin reaction
Named after	Henry Drysdale Dakin
Reaction type	Organic redox reaction
Identifiers
Organic Chemistry Portal	dakin-reaction
RSC ontology ID	RXNO:0000169

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.

The Dakin oxidation starts with nucleophilic addition of a hydroperoxide anion to the carbonyl carbon, forming a tetrahedral intermediate (2). The intermediate collapses, causing [1,2]-aryl migration, hydroxide elimination, and formation of a phenyl ester (3). The phenyl ester is subsequently hydrolyzed: nucleophilic addition of hydroxide from solution to the ester carbonyl carbon forms a second tetrahedral intermediate (4), which collapses, eliminating a phenoxide and forming a carboxylic acid (5). Finally, the phenoxide extracts the acidic hydrogen from the carboxylic acid, yielding the collected products (6).

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