The mechanism for the photo-Fries rearrangement of phenyl acetate and biphe
nylyl acetates were reinvestigated in phenol (or phenol derivatives) contai
ning media. The results showed that the phenol (or phenol derivatives) whic
h is the most common by-product of Fries reaction reacts with acyl radical
to give Fries-product. These phenol (or phenol derivatives) contributions t
o the Fries-products were suggested as the Trivial mechanism for the photo-
Fries reaction.