Preparation of Ortho-Substituted Benzoic Acids by the Copper(II)-Catalyzed Reaction of Diphenyliodonium-2-carboxylate with Anilines and Other Nucleophiles

Article abstract of DOI:10.1021/jo01299a020

Diphenyliodonium-2-carboxylate (DPIC) reacts readily in copper ion catalyzed condensations with a variety of nucleophiles to give ortho-substituted benzoic acids.These reactions occur at temperatures (80-100 deg C) below those at which benzyne formation and other side reactions become important.The nature of the Cu(II) catalysis appears to be different from the more common Cu(I) catalysis of diaryliodonium reactions in that high specificity in the displacement reaction is retained.Products obtained directly from DPIC condensations include N-<2,6-dichloro-3-(dimethylsulfamoyl)phenyl>anthranilic acid (5b), N-methyl-N-phenylanthranilic acid (5c), N-mesyl-N-(2,3-dimethylphenyl)anthranilic acid (5d), N-(3-chloro-2-methylphenyl)-N-tosylanthranilic acid (5e), and o-(2,3-dimethylphenoxy)benzoic acid (5f).Compound 5d has been cyclized to N-(2,3-dimethylphenyl)-1H-2,1-benzothiazin-4(3H)-one 2,2-dioxide (6).