Arenes to Arenecarboxylic Acids

The condensation of aromatic compounds with tellurium tetrachloride produces aryl tellurium trichlorides that can be converted to diaryl ditelluriums, which, in turn, can be reduced to arenetellurols. These tellurols condense with alkyl halides to give aryl alkyl telluriums. When these aryl alkyl telluriums are carbonylated with carbon monoxide in the presence of palladium(II) chloride or acetate, arenecarboxylic acids are formed 

The yields of benzoic acid in these reactions may reach 98% . In many cases the yields of alkanoic acids are very low. 

Bis[4-methoxyphenyl] tellurium, obtained from 4-methoxybenzene and tellurium tetrachloride and reduction of the resultant bis[4-methoxyphenyl] tellurium dichloride, was converted to methyl 4-methoxybenzoate in 99% yieldh Methyl benzoate was similarly obtained from diphenyl tellurium in yields higher than 90%. These reactions can be carried out with catalytic amounts of palladium(II) chloride when copper(II) chloride is used as an oxidant f 

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