Synfacts 2005(2): 0268-0268  
DOI: 10.1055/s-2005-916094
Polymer-Supported Synthesis
© Georg Thieme Verlag Stuttgart · New York

An Efficient Recyclable Silica-Supported Ruthenium Catalyst

Contributor(s): Yasuhiro Uozumi, Tomohiko Beppu
P.-N. Liu, P.-M. Gu, J.-G. Deng, Y.-Q. Tu*, Y.-P. Ma
Lanzhou University, P. R. of China
Further Information

Publication History

Publication Date:
25 October 2005 (online)

Significance

The N-(p-tosylsulfonyl)-1,2-diphenylethylenediamine (TsDPEN) ligands anchored on silica-based solid supports 1-4 were prepared and applied to the ruthenium-catalyzed asymmetric transfer hydrogenation of C=O and C=N double bonds. Of the immobilized ligands, the amorphous silica gel-supported 1 was found to give high catalytic activity and stereoselectivity. The asymmetric hydrogenation of acetophenone took place in HCOOH/Et3N at 40 °C in the presence of a ruthenium complex generated in situ by mixing [RuCl2(p-cymene)]2 and ligand 1 to give 99% yield (conversion) of phenethylalcohol with 97% ee. Nine substrates and seven times recycling were examined.