The photochemical rearrangement of aromatic ethers

The Photo-Claisen reaction is one of the classical photochemical rearrangements of aromatic molecules and is mechanistically related to the Photo-Fries reaction. It consists in the formation of ortho- and para-substituted phenols from phenyl ethers after irradiation. The reaction mechanism involves a singlet radical pair within a solvent cage and because of its simplicity constitutes a suitable model for the study of analogous reactions.