Heterogeneous asymmetric reactions 34.: New data in the enantioselective hydrogenation of ethyl pyruvate catalyzed by cinchona alkaloid-modified Pt/Al2O3 in toluene

被引：23

作者：

Bartók, M

Balázsik, K

Bartók, T

Kele, Z

机构：

[1] Univ Szeged, Organ Catalysis Res Grp, Dept Organ Chem, H-6720 Szeged, Hungary

[2] Cereal Res Inst, Analyt Lab, H-6701 Szeged, Hungary

[3] Univ Szeged, Dept Med Chem, H-6720 Szeged, Hungary

来源：

CATALYSIS LETTERS | 2003年 / 87卷 / 3-4期

基金：

匈牙利科学研究基金会;

关键词：

enantioselective; hydrogenation; Pt/Al2O3; cinchona alkaloids; ethyl pyruvate; solvent effect;

D O I：

10.1023/A:1023463811443

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The enantioselective hydrogenation of ethyl pyruvate (EtPy) on Pt-alumina (E 4759) catalyst modified by dihydrocinchonidine (DHCD) at a hydrogen pressure of 1 bar in toluene was studied. The effects of the modifier concentration (0.001-1 mmol l(-1)) and temperature (-10, 0, 24 degreesC) on the reaction rate and the enantioselectivity have been studied. Under mild experimental conditions (hydrogen pressure: 1 bar, temperature: -10 degreesC, DHCD concentration: 0.1 mmol l(-1)) an optical yield of 88% can be achieved. When EtPy hydrogenation was studied in AcOH under identical conditions, it was established that the DHCD/Pt-surf ratio necessary for achieving maximum enantioselectivity is highly solvent dependent: this ratio is 0.007 in AcOH and 0.12 in toluene. This large difference in DHCD/Pt-surf may be a reflection of a difference in reaction mechanism.

引用

页码：235 / 240

页数：6

共 27 条

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