Heterogeneous Enantioselective Hydrogenation of Ethyl Pyruvate Catalyzed by Cinchona-Modified Pt Catalysts: Effect of Modifier Structure

Autor:	M. Studer, and W. Lottenbach, H. P. Jalett, H. U. Blaser
Rok vydání:	2000
Předmět:	biology Quinoline Substituent Enantioselective synthesis Cinchona General Chemistry Cinchonine Cinchona Alkaloids biology.organism_classification Biochemistry Catalysis chemistry.chemical_compound Colloid and Surface Chemistry chemistry Organic chemistry Cinchonidine Quinuclidine
Zdroj:	Journal of the American Chemical Society. 122:12675-12682
ISSN:	1520-5126 0002-7863
DOI:	10.1021/ja003259q
Popis:	The effect of the structure of chiral modifiers derived from natural cinchona alkaloids on the enantioselectivity and rate of the Pt/Al2O3-catalyzed hydrogenation of ethyl pyruvate was investigated. The influence of the following structural elements was studied: the cinchonidine versus the cinchonine backbone; effect of the nature and the size of substituents attached to C9; effect of partial hydrogenation of the quinoline ring; effects of changes of the substituent at the quinuclidine moiety. The strongest effects on ee and somewhat less on rate were observed for changes in the O−C9−C8−N part of the cinchona alkaloid and for partial or total hydrogenation of the quinoline rings. The nature of the substituents in the quinuclidine part had a comparably minor influence. The solvent was found to have a significant effect on enantioselectivity and rate. In acetic acid, the best results were obtained with O-methyl-10,11-diydrocinchonidine (ee's up to 93%), whereas dihydrocinchonidine was the most effective mo...
Databáze:	OpenAIRE
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