The Dakin reaction refers to the transformation of ortho- or para-hydroxy aromatic aldehydes or ketones into corresponding phenols under basic conditions using hydrogen peroxide. This reaction was discovered by Henry Drysdale Dakin in 1909, and is named in his honor. It is an efficient method for synthesizing polyhydroxy aromatic compounds.

• Reagents: Hydrogen peroxide, base

• Reactants: Ortho- or para-hydroxy aromatic aldehydes or ketones

• Products: Phenols

• Reaction Type: Oxidation

Experimental Tips:

• Aromatic aldehydes are more reactive than aromatic ketones due to the higher electrophilicity of the aldehyde carbonyl carbon.

• Common bases used include sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide.

• Aromatic aldehydes or ketones bearing alkoxy or amino groups can also undergo this reaction.

• A urea–hydrogen peroxide complex (UHP) can be used as an alternative oxidant. UHP is stable and easy to handle, making it a convenient reagent for the Dakin reaction.

Reaction Mechanism

Key References:

• Original Publication

  • Dakin, H.D., American Chemical Journal, 1909, 42(6), 477–498.

• Notable Citations

  • Oxidation of aromatic aldehydes and ketones by H₂O₂/CH₃ReO₃ in ionic liquids: a catalytic efficient reaction to achieve dihydric phenols, Tetrahedron, 2005, 61(7), 1821–1825.

  • The Urea–Hydrogen Peroxide Complex: Solid-State Oxidative Protocols for Hydroxylated Aldehydes and Ketones (Dakin Reaction), Nitriles, Sulfides, and Nitrogen Heterocycles, Org. Lett., 1999, 1(2), 189–192.

  • Organocatalytic Dakin Oxidation by Nucleophilic Flavin Catalysts, Org. Lett., 2012, 14(11), 2806–2809.