Efficient heterogeneous asymmetric transfer hydrogenation catalyzed by recyclable silica-supported ruthenium complexes

Abstract

Easily accessible N-(p-tolylsulfonyl)-1,2-diphenylethylenediamine-(TsDPEN-) derived organic-inorganic hybrid ligands were prepared and applied to the heterogeneous asymmetric transfer hydrogenation in traditional HCO 2H/NEt3 and in water with HCO2Na as the hydrogen source and sodium dodecyl sulfate (SDS) as the phase-transfer catalyst. The reactions demonstrated high catalytic activities and excellent enantioselectivities for most aromatic ketones and the imine tested, with results similar to those in homogeneous catalysis. In particular, this heterogeneous catalyst can be readily recovered and used in multiple consecutive catalytic runs with the high enantioselectivity maintained both in HCO 2H/NEt3 and in water. © Wiley-VCH Verlag GmbH & Co. KGaA, 2005.