Issue 4, 2012

Asymmetric hydrogenation of C[double bond, length as m-dash]C double bonds using Rh-complex under homogeneous, heterogeneous and continuous mode conditions

Abstract

A green process for enantioselective hydrogenation of dehydroamino acid derivatives and dimethyl itaconate with a rhodium catalyst modified by a new phosphine–phosphoramidite has been developed providing 97.7–99.8% enantioselectivity in green solvents such as ethylene carbonate and propylene carbonate. The L-DOPA precursor was obtained by simple filtration in 71% yield with 99.5% ee. Dimethyl itaconate was hydrogenated under solvent-free condition at 50 °C with 98.7% ee. The new rhodium complex was heterogenized on a mesoporous Al2O3 support using phosphotungstic acid (PTA) as an anchoring agent and tested in heterogeneous batch and flow reaction modes. The supported catalyst was reused eight times in the batch mode with over 97% ee and used over 12 hours in the flow reaction mode with an average of 97% ee in the asymmetric hydrogenation reaction of (Z)-α-acetamidocinnamic acid methyl ester.

Graphical abstract: Asymmetric hydrogenation of C [[double bond, length as m-dash]] C double bonds using Rh-complex under homogeneous, heterogeneous and continuous mode conditions

Supplementary files

Article information

Article type
Paper
Submitted
12 Nov 2011
Accepted
23 Jan 2012
First published
01 Mar 2012

Green Chem., 2012,14, 1146-1151

Asymmetric hydrogenation of C[double bond, length as m-dash]C double bonds using Rh-complex under homogeneous, heterogeneous and continuous mode conditions

S. Balogh, G. Farkas, J. Madarász, Á. Szöllősy, J. Kovács, F. Darvas, L. Ürge and J. Bakos, Green Chem., 2012, 14, 1146 DOI: 10.1039/C2GC16447G

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