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Search for "asymmetric hydrogenation" in Full Text gives 30 result(s) in Beilstein Journal of Organic Chemistry.
A practical two-step procedure for the preparation of enantiopure pyridines: Multicomponent reactions of alkoxyallenes, nitriles and carboxylic acids followed by a cyclocondensation reaction
Beilstein J. Org. Chem. 2011, 7, 962–975, doi:10.3762/bjoc.7.108
- metal-catalyzed processes and for the construction of supramolecular architectures [13]. Pyridines with chiral side chains are widely employed as ligands in asymmetric transformations, for instance, in the asymmetric hydrogenation of olefins, in enantioselective additions of metal organyls to aldehydes
A two step synthesis of a key unit B precursor of cryptophycins by asymmetric hydrogenation
Beilstein J. Org. Chem. 2011, 7, 243–245, doi:10.3762/bjoc.7.32
- yields from commercially available starting materials has been developed. The key step is an asymmetric hydrogenation using the commercially available [(COD)Rh-(R,R)-Et-DuPhos]BF4 catalyst. The synthetic route provides the advantage of less synthetic steps, proceeds with high yields and
- enantioselectivity, and avoids hazardous reaction conditions. Keywords: amino acid; asymmetric hydrogenation; cryptophycin; DuPhos; Introduction Cryptophycins are macrocyclic depsipeptides, which show very high cytotoxicity even against multidrug-resistant cell lines. They inhibit mitosis of eukaryotic cells by
- unit B precursor 4 (Scheme 1) from commercially available non-toxic starting materials based on an asymmetric hydrogenation approach to make the unit B precursor synthesis shorter and safer. In general, there is also a whole variety of possible stereoselective synthetic methods available to synthesize
Can we measure catalyst efficiency in asymmetric chemical reactions? A theoretical approach
Beilstein J. Org. Chem. 2009, 5, No. 67, doi:10.3762/bjoc.5.67
- asymmetric hydrogenation, which gives a product of 79% ee, is employed in the industrial multi-tonne synthesis of (S)-metolachlor [3]. An instructive comparison may be made between an antibody capable of catalysing an intramolecular, asymmetric aldol reaction and proline, capable of catalysing the same
- extraordinary efficiency of ligated transition metal catalysts in asymmetric hydrogenation. An analysis of the unit cost of each catalyst reveals these to span a very wide range, with only the amino acid proline comparing favourably with the hydrogenation systems. The ACE formula permits a comparison between
Asymmetric reactions in continuous flow
Beilstein J. Org. Chem. 2009, 5, No. 19, doi:10.3762/bjoc.5.19
- observed to be higher in the microreactor. A single-channel, falling film microreactor designed specifically for efficient gas-liquid phase contact was used to screen the asymmetric hydrogenation of (Z)-methyl acetamidocinnamate 4 and related substrates (Scheme 2) [13][14]. Seventeen chiral phosphines were
- alternative reaction medium to traditional organic solvents is attractive not only for environmental reasons, but also because of its high miscibility with gases, and its ease of removal from the product (simply by depressurization) [46]. In an early example of asymmetric hydrogenation in flow, ethyl pyruvate
- was reduced using a cinchonidine-modified Pt/Al2O3 catalyst in a fixed bed reactor in both supercritical carbon dioxide and ethane [47]. Poliakoff and co-workers have investigated the continuous asymmetric hydrogenation of dimethyl itaconate in scCO2 [48][49]. By using the catalyst [Rh(COD)2(nbd
Large- scale ruthenium- and enzyme- catalyzed dynamic kinetic resolution of (rac)-1-phenylethanol
Beilstein J. Org. Chem. 2007, 3, No. 50, doi:10.1186/1860-5397-3-50
- natural products. [1][2][3][4] A few methods have been developed for the enantioselective synthesis of chiral alcohols including catalytic asymmetric hydrogenation [5][6][7][8][9][10][11][12][13][14] and enantioselective hydride addition [15][16] of prochiral ketones, asymmetric dialkylzinc addition to
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