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
Mechanism
Top Citations
Related Reactions
- Electrophilic Aromatic Substitution
- Friedel-Crafts Acylation
Related Compounds
- Lewis Acid
- Acid