A Lewis Acid Catalyzed 1,2 Aryl Shift in α-Haloalkyl Aryl Acetals: A Convenient Route to α-Arylalkanoic Acids

Article abstract of DOI:10.1021/jo00172a041

A new method for the synthesis of α-arylalkanoic acids is given, based on Lewis acid promoted rearrangement of acetals of primary and secondary α-haloalkyl aryl ketones (halo = Br, Cl) in hydrocarbon solvents.The reaction is selective, providing the esters of α-arylalkanoic acids in almost quantitative yields.The ability of "soft and borderline" Lewis acids in activating the carbon-halogen bond is compared with that of silver salts.The reaction mechanism is discussed.The present synthesis has been applied to some α-arylpropionic acids well-known as antiinflammatory drugs.