The Fries Rearrangement of 4-Biphenylyl Benzoate and 4-Biphenyly1 Acetate

Abstract

When a mixture of 4 -biphenyly1b enzoate (1) and anhydrous aluminum chloride ( AlCl₃w) as boiled in o-dichlorobenzene, 4-hydroxy-3-biphenylyl phenyl ketone (3) was obtained as a main product together with a small amount of 4'-hydroxy-4-biphenylyl phenyl ketone (4). A rearrangement product 4-hydroxy-3-biphenylyl methyl ketone (5) was given in the reaction of 4 -biphenylyl acetate (2) with AlCl₃ under the same reaction conditions. Corresponding amounts 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 other hand, a small amount of 1 and 3 was detected in the reaction of 4with AlCl₃F. ries rearrangement of 1 and 2 may proceed predominantly via an intramolecular pathway.