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Synfacts 2009(2): 0230-0230  
DOI: 10.1055/s-0028-1087627
Polymer-Supported Synthesis
© Georg Thieme Verlag Stuttgart ˙ New York

Asymmetric Hydrogenation of Ketones Using Ir/SiO2/Ph3P/Diamine Catalysts

Contributor(s): Yasuhiro Uozumi, Toshimasa Suzuka
H.-y. Jiang, C.-f. Yang, C. Li, H.-y. Fu, H. Chen*, R.-x. Li, X.-j. Li
Sichuan University, Chengdu, P. R. of China
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Publikationsverlauf

Publikationsdatum:
22. Januar 2009 (online)

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Significance

Silica gel-supported iridium/phosphine/diamine complexes were prepared and found to catalyze the asymmetric hydrogenation of aromatic ketones. Thus, Ph3P-stabilized Ir/SiO2 was obtained in two steps (silica gel, H2IrCl6, Ph3P; formaldehyde, 110 ˚C, i-PrOH). The resulting SiO2/Ir/Ph3P composite was complexed with cinchona alkaloid based diamines a and b to give solid-supported catalysts 1a and 1b, respectively. Enantioselective hydrogenation of 2-chloroaceto­phenone under H2 (6.0 MPa) was carried out with 3 mol% Ir of the catalyst 1a in MeOH to afford (S)-1-(2-chlorophenyl)ethanol in 80% yield with 96% ee.