The Fries rearrangement of 4-biphenylyl benzoate and 4-biphenylyl acetate

When a mixture of 4-biphenylyl benzoate (1) and anhydrous aluminum chloride (AlCl3) was boiled in o-dichlorobenzene, 4-hydroxy-3-biphenylyl phenyl ket one (3) was obtained as a main product together with a small amount of 4'-h ydroxy-4-biphenylyl phenyl ketone (4). A rearrangement product 4-hydroxy-3- biphenylyl methyl ketone (5) was given in the reaction of 4-biphenylyl acet ate (2) with AlCl3 under the same reaction conditions. Corresponding amount s of 4-biphenylol were obtained as a by-product in the Fries rearrangement of 1 and 2 under the reaction conditions. In these reactions, the reaction of 2 seems to proceed faster than 1. Products distributions (rearrangement products, 3 and 5, and 4-biphenylol) in the Fries rearrangement of 1 and 2 were remarkably different depending upon the reaction temperature. On the o ther hand, a small amount of 1 and 3 was detected in the reaction of 4 with AlCl3. Fries rearrangement of 1 and 2 may proceed predominantly via an int ramolecular pathway.