Catalytic asymmetric syntheses II. Hydrogenation of α,β-unsaturated ketones using chiral ruthenium complexes
作者:Viviane Massonneau、Paul Le Maux、Gérard Simonneaux
DOI:10.1016/0022-328x(87)80210-3
日期:1987.6
inthe presence of HRuCl-(TBPC)2 (TBPC = (−)-trans-1,2-bis(diphenylphosphinomethyl)cyclobutane) to give ketones with a maximum optical purity of 62%. Factors affecting the stereoselectivity of the catalytic reaction are discussed.
Identification, Characterization, and Application of Three Enoate Reductases from<i>Pseudomonas putida</i>in In Vitro Enzyme Cascade Reactions
作者:Christin Peters、Regina Kölzsch、Maria Kadow、Lilly Skalden、Florian Rudroff、Marko D. Mihovilovic、Uwe T. Bornscheuer
DOI:10.1002/cctc.201300957
日期:2014.4
Enoatereductases are versatile enzymes for the enantio‐ and regioselective addition of hydrogen to double bonds. We identified three EREDs (XenA, XenB, NemA) from Pseudomonas putida ATCC 17453 through a sequence motif search. In addition to cloning, functional expression, and biochemical characterization of these enzymes, the enoatereductases were also applied in enzymecascadereactions in combination
strains) and biodegradability (OECD 301D) of the CILs at the same time as undertaking the asymmetric catalysis study. The Pd-catalyzed enantioselective hydrogenation of the carbon–carbon double bond of α,β-unsaturatedketones under mild conditions (room temperature, 1 atm of H2) in different solvents with CILs present. The best results were obtained in i-PrOH after 18 hours of reaction with a i-PrOH/IL ratio
of a broad library of new P-chirogenic Xantphos ligands is reported. A special feature is 2,7-di-tert.-butyl substituents in the backbone which requires the modification of the original synthetic approach. In comparison to related ligands reported formerly the substitution has a considerable influence on the results (yield and % e.e.) of metal catalyzed reactions, e.g. asymmetric rhodium catalyzed hydrogenation
Stereodifferentiation in heterogeneous catalytic hydrogenation. Kinetic resolution and asymmetric hydrogenation in the presence of (S)-proline: Catalyst-dependent processes
作者:Nóra Győrffy、Antal Tungler、Mátyás Fodor
DOI:10.1016/j.jcat.2009.10.018
日期:2010.3
5,5-trimethyl cyclohexanone (TMCH) and asymmetrichydrogenation of isophorone (3,5,5-trimethyl cyclohex-2-enone, IP) were investigated on different Pd catalysts in the presence of (S)-proline (Pr). It could be proven that in isophorone hydrogenation the optically active TMCH was formed not only by kinetic resolution but also through asymmetric CC hydrogenation. The activity and stereoselectivity of