کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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67216 | 48471 | 2009 | 5 صفحه PDF | دانلود رایگان |
A series of silica (SiO2) supported iridium catalysts stabilized by cinchona alkaloids was prepared and applied in the heterogeneous asymmetric hydrogenation of acetophenone. Cinchona alkaloids exhibited a marked ability to stabilize and disperse the Ir particles. In the presence of (1S,2S)-diphenylethylenediamine ((1S,2S)-DPEN)) as chiral modifier, the cinchonidine (CD) stabilized catalyst 5%Ir/2CD-SiO2 exhibited excellent catalytic performance in the asymmetric hydrogenation of acetophenone in MeOH. Under the optimum conditions, the ee value of (R)-phenylethanol achieved 79.8% and no other product was produced, a higher enantioselectivity than that reported up to now for acetophenone hydrogenation catalyzed by the supported metal catalysts modified by chiral reagents. In particular, a synergistic effect between (1S,2S)-DPEN and CD was observed, which significantly accelerated the reaction rate and enhanced the enantioselectivity. The catalyst can be reused several times without a significant loss of activity and enantioselectivity.
A series of silica (SiO2) supported iridium catalysts stabilized by cinchona alkaloids was prepared and firstly applied in the heterogeneous asymmetric hydrogenation of acetophenone. In the presence of (1S,2S)-diphenylethylenediamine ((1S,2S)-DPEN)) as chiral modifier, the cinchonidine (CD) stabilized catalyst 5%Ir/2CD-SiO2 exhibits excellent catalytic performance, the ee value of (R)-phenylethanol achieving 79.8%.Figure optionsDownload as PowerPoint slide
Journal: Journal of Molecular Catalysis A: Chemical - Volume 300, Issues 1–2, 2 March 2009, Pages 98–102