Thermal effects in the organocatalytic asymmetric Mannich reaction.
The proline-catalyzed direct asymmetric Mannich reaction between cyclohexanone, formaldehyde, and various anilines is thermally accelerated. With only 0.5 mol % of catalyst, Mannich products with up to 98% ee have been obtained after a short period of time in reactions performed under microwave irradiation. In situ reduction of the resulting ketones affords N-aryl amino alcohols in up to 86% yield.
Rodríguez
Belén
B
Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52056 Aachen, Germany.
Bolm
Carsten
C