The Fries rearrangement uses a Lewis or Brӧnsted acid to synthesize ortho- and/or para substituted phenolic ketones and aldehydes from phenolic esters. First an acylium cation is produced, which facilitates an electrophilic aromatic substitution to afford the ortho- and/or para-product. The ortho product is favored with high temperatures and no solvent, while the para product is favored with low temperatures and increasing solvent polarity.

  • Reagents: Lewis or Brӧnsted Acid (HF, HClO4, PPA) or Solid Acid (e.g. Zeolites) or hv (called Photo-Fries Rearrangement)
  • Reactant: Phenolic Ester (Electron-donating groups on the phenol favored)
  • Product: Ortho and/or Para Substituted Phenolic Ketones or Aldehydes
  • Type of Reaction: Phenol Ester Rearrangement


Top Citations

Related Reactions

  • Electrophilic Aromatic Substitution
  • Friedel-Crafts Acylation

Related Compounds

  • Lewis Acid
  • Acid
By shuhan yang


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