SPECIALTOPIC	Synthesis 2002: 1607-1610 DOI: 10.1055/s-2002-33349
© Georg Thieme Verlag Stuttgart · New York
Transfer Hydrogenation in Ionic Liquids under Microwave Irradiation
Herwig Bertholda,b, Theo Schotten*a, Helmut Hönigb
a Lilly Forschung GmbH, 22419 Hamburg, Germany (a Division of Eli Lilly Research Laboratories) Fax: +49(40)52724614; e-Mail: berthold_herwig@lilly.com ; e-Mail: schotten_theo@lilly.com; b Technical University Graz, Institute for Organic Chemistry, Stremayrgasse 16, 8010 Graz, Austria Fax: +43(316)8738740; e-Mail: berthold@sbox.tu-graz.ac.at; helmut.hoenig@TUGraz.at;
Received 7 June 2002

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.

Key words

microwaves - room temperature ionic liquid - catalytic transfer hydrogenation - unsaturated compounds - formate salts