Chemoselectivity of cobalt-catalysed carbonylation—A reliable platform for the synthesis of fluorinated benzoic acids

The cobalt-catalysed methoxycarbonylation of polysubstituted bromo,fluoro- and chloro,fluorobenzenes and 1,2,4-trichlorobenzene with emphasis on the chemo- and regio-selectivity of the reaction is described. The structures of isolated products of 1,4-dichloro-2-fluorobenzene carbonylation were determined by single-crystal X-ray diffraction. The fact that the fluorine substituents in the studied compounds remain intact indicates in favor of the anion-radical activation of aryl halides by a cobalt catalyst. For the first time, a universal method of preparation of the various fluorobenzoic acid derivatives from available raw materials with a good yield has been elaborated.