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Dakin oxidation : ウィキペディア英語版 | 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. ==Reaction mechanism== The Dakin oxidation starts with nucleophilic addition of a hydroperoxide anion to the carbonyl carbon, forming a tetrahedral intermediate (2). The intermediate collapses, causing ()-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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