Exploitation of Synthetic Reactions via C-H Bond Activation by Transition Metal Catalysts. Carboxylation and Aminomethylation of Alkanes or Arenes

Unactivated alkanes, including methane, ethane, and propane, can be carboxylated with CO by palladium and/or copper catalysts in TFA at 80 °C with high turnover numbers of the catalysts. The Pd-Cu mixed catalyst (1:1) exhibits extremely high activity for the carboxylation of alkanes other than methane. Methane is best transformed to acetic acid by the Cu catalyst. The reaction of methane with CO₂ also gives acetic acid. The present method also causes a quantitative conversion of arenes such as benzene and chlorobenzene into the corresponding carboxylic acids with 1 atm CO at room temperature. In addition, gaseous alkanes can be aminomethylated with tert-amine N-oxides by Cu catalysts in TFA at 150°C.

C-H bond activation - carboxylation - aminomethylation - palladium - copper