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

Abstract

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.