Transfer Hydrogenation in Ionic Liquids under Microwave Irradiation

Abstract

Catalytic transfer hydrogenation (CTH) of different homo- or heteronuclear organic compounds was performed in a room temperature ionic liquid (RTIL) N-butyl-N′-methylimidazolium hexafluorophosphate, ([BMIM]+ [PF6]-) (1) as solvent heated by microwave irridiation. Formate salts such as ammonium formate and triethylammonium formate were used as a hydrogen source in the reaction catalyzed by palladium on carbon. Essentially pure products could be isolated in moderate to excellent yields by simple liquid-liquid extraction with methyl tert-butyl ether (MTBE). Recycling of the catalyst/solvent system was possible.