101
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Yukawa T, Seelig B, Xu Y, Morimoto H, Matsunaga S, Berkessel A, Shibasaki M. Catalytic Asymmetric Aza-Morita−Baylis−Hillman Reaction of Methyl Acrylate: Role of a Bifunctional La(O-iPr)3/Linked-BINOL Complex. J Am Chem Soc 2010; 132:11988-92. [DOI: 10.1021/ja103294a] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Takafumi Yukawa
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan, Department of Chemistry, University of Cologne, Greinstr. 4, 50939 Cologne, Germany, and Institute of Microbial Chemistry, Tokyo, Kamiosaki 3-14-23, Shinagawa-ku, Tokyo 141-0021, Japan
| | - Bianca Seelig
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan, Department of Chemistry, University of Cologne, Greinstr. 4, 50939 Cologne, Germany, and Institute of Microbial Chemistry, Tokyo, Kamiosaki 3-14-23, Shinagawa-ku, Tokyo 141-0021, Japan
| | - Yingjie Xu
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan, Department of Chemistry, University of Cologne, Greinstr. 4, 50939 Cologne, Germany, and Institute of Microbial Chemistry, Tokyo, Kamiosaki 3-14-23, Shinagawa-ku, Tokyo 141-0021, Japan
| | - Hiroyuki Morimoto
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan, Department of Chemistry, University of Cologne, Greinstr. 4, 50939 Cologne, Germany, and Institute of Microbial Chemistry, Tokyo, Kamiosaki 3-14-23, Shinagawa-ku, Tokyo 141-0021, Japan
| | - Shigeki Matsunaga
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan, Department of Chemistry, University of Cologne, Greinstr. 4, 50939 Cologne, Germany, and Institute of Microbial Chemistry, Tokyo, Kamiosaki 3-14-23, Shinagawa-ku, Tokyo 141-0021, Japan
| | - Albrecht Berkessel
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan, Department of Chemistry, University of Cologne, Greinstr. 4, 50939 Cologne, Germany, and Institute of Microbial Chemistry, Tokyo, Kamiosaki 3-14-23, Shinagawa-ku, Tokyo 141-0021, Japan
| | - Masakatsu Shibasaki
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan, Department of Chemistry, University of Cologne, Greinstr. 4, 50939 Cologne, Germany, and Institute of Microbial Chemistry, Tokyo, Kamiosaki 3-14-23, Shinagawa-ku, Tokyo 141-0021, Japan
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102
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Berkessel A, Ong MC, Nachi M, Neudörfl JM. Enantiopure Monoprotected cis-1,2-Diaminocyclohexane: One-Step Preparation and Application in Asymmetric Organocatalysis. ChemCatChem 2010. [DOI: 10.1002/cctc.201000104] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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103
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Berkessel A, Seelig B, Schwengberg S, Hescheler J, Sachinidis A. Chemically Induced Cardiomyogenesis of Mouse Embryonic Stem Cells. Chembiochem 2009; 11:208-17. [DOI: 10.1002/cbic.200900345] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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104
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Baer K, KrauÃer M, Burda E, Hummel W, Berkessel A, Gröger H. Sequenzielle und modulare Synthese von chiralen 1,3-Diolen mit zwei Stereozentren: Zugang zu allen vier Stereoisomeren durch Kombination von Organo- und Biokatalyse. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200900582] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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105
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Baer K, KrauÃer M, Burda E, Hummel W, Berkessel A, Gröger H. Sequential and Modular Synthesis of Chiral 1,3-Diols with Two Stereogenic Centers: Access to All Four Stereoisomers by Combination of Organo- and Biocatalysis. Angew Chem Int Ed Engl 2009; 48:9355-8. [DOI: 10.1002/anie.200900582] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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106
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107
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Doroshyenko O, Fuhr U, Kunz D, Frank D, Kinzig M, Jetter A, Reith Y, Lazar A, Taubert D, Kirchheiner J, Baum M, Eisenbrand G, Berger FI, Bertow D, Berkessel A, Sörgel F, Schömig E, Tomalik-Scharte D. In vivo Role of Cytochrome P450 2E1 and Glutathione-S-Transferase Activity for Acrylamide Toxicokinetics in Humans. Cancer Epidemiol Biomarkers Prev 2009; 18:433-43. [DOI: 10.1158/1055-9965.epi-08-0832] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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108
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Berkessel A, Brandenburg M, Schäfer M. Mass-Spectrometric and Kinetic Studies on the Mechanism and Degradation Pathways of Titanium Salalen Catalysts for Asymmetric Epoxidation with Aqueous Hydrogen Peroxide. Adv Synth Catal 2008. [DOI: 10.1002/adsc.200700601] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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109
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Berkessel A. Asymmetric Epoxidation of Olefins with Hydrogen Peroxide—Catalysis by an Aspartate-Containing Tripeptide. Angew Chem Int Ed Engl 2008; 47:3677-9. [DOI: 10.1002/anie.200705326] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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110
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Berkessel A. Asymmetrische Epoxidierung von Olefinen mit Wasserstoffperoxid – Katalyse durch ein Aspartat enthaltendes Tripeptid. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200705326] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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111
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Sachinidis A, Sotiriadou I, Seelig B, Berkessel A, Hescheler J. A chemical genetics approach for specific differentiation of stem cells to somatic cells: a new promising therapeutical approach. Comb Chem High Throughput Screen 2008; 11:70-82. [PMID: 18220544 DOI: 10.2174/138620708783398322] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cell replacement therapy of severe degenerative diseases such as diabetes, myocardial infarction and Parkinson's disease through transplantation of somatic cells generated from embryonic stem (ES) cells is currently receiving considerable attention for the therapeutic applications. ES cells harvested from the inner cell mass (ICM) of the early embryo, can proliferate indefinitely in vitro while retaining the ability to differentiate into all somatic cells thereby providing an unlimited renewable source of somatic cells. In this context, identifying soluble factors, in particular chemically synthesized small molecules, and signal cascades involved in specific differentiation processes toward a defined tissue specific cell type are crucial for optimizing the generation of somatic cells in vitro for therapeutic approaches. However, experimental models are required allowing rapid and "easy-to-handle" parallel screening of chemical libraries to achieve this goal. Recently, the forward chemical genetic screening strategy has been postulated to screen small molecules in cellular systems for a specific desired phenotypic effect. The current review is focused on the progress of ES cell research in the context of the chemical genetics to identify small molecules promoting specific differentiation of ES cells to desired cell phenotype. Chemical genetics in the context of the cell ES-based cell replacement therapy remains a challenge for the near future for several scientific fields including chemistry, molecular biology, medicinal physics and robotic technologies.
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Affiliation(s)
- Agapios Sachinidis
- Centre of Physiology and Pathophysiology, Institute of Neurophysiology, Cologne, Germany.
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112
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Berkessel A, Rollmann C, Chamouleau F, Labs S, May O, Gröger H. Practical Two-Step Synthesis of an Enantiopure Aliphatic Terminal (S)-Epoxide Based on Reduction of Haloalkanones with “Designer Cells”. Adv Synth Catal 2007. [DOI: 10.1002/adsc.200700244] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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113
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Berkessel A, Brandenburg M, Leitterstorf E, Frey J, Lex J, Schäfer M. A Practical and Versatile Access to Dihydrosalen (Salalen) Ligands: Highly Enantioselective TitaniumIn Situ Catalysts for Asymmetric Epoxidation with Aqueous Hydrogen Peroxide. Adv Synth Catal 2007. [DOI: 10.1002/adsc.200700221] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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114
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Slagt VF, Kaiser P, Berkessel A, Kuil M, Kluwer AM, van Leeuwen PWNM, Reek JNH. Fine-Tuning Ligands for Catalysis Using Supramolecular Strategies. Eur J Inorg Chem 2007. [DOI: 10.1002/ejic.200700550] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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115
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Berkessel A, Adrio JA, Hüttenhain D, Neudörfl JM. Unveiling the "booster effect" of fluorinated alcohol solvents: aggregation-induced conformational changes and cooperatively enhanced H-bonding. J Am Chem Soc 2007; 128:8421-6. [PMID: 16802806 DOI: 10.1021/ja0545463] [Citation(s) in RCA: 252] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The influence of conformation and aggregation on the hydrogen bond donor ability of fluorinated alcohol solvents [1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and 1-phenyl-2,2,2-trifluoroethanol (PhTFE)] was explored theoretically (DFT) and experimentally (NMR, kinetics, crystal structure analyses). The detailed DFT analysis revealed a pronounced dependence of the H-bond donor ability on the conformation along the CO-bond of the monomeric alcohols. The donor orbital energy (sigma*(OH)) decreases and the molecular dipole moment (mu) increases drastically from the antiperiplanar (ap) to the synperiplanar (sp) H(C)COH conformation. The kinetics of olefin epoxidation with H(2)O(2) in HFIP indicate higher order solvent aggregates (2-3 monomers) to be responsible for the activation of the oxidant. Single-crystal X-ray analyses of HFIP and PhTFE confirmed the existence of H-bonded aggregates (infinite helices, ribbons, and cyclic oligomers) and the predominance of sc to sp conformations of the fluoroalcohol monomers. These aggregate structures served as the basis for a DFT analysis of the H-bond donor ability at the terminal hydroxyl group of HFIP mono- to pentamers. Both the LUMO energy and the natural charge of the terminal hydroxyl proton indicated a substantial cooperative influence of dimerization and trimerization on the H-bond donor ability. We therefore conclude that dimers and trimers, with the individual monomers in their sc to sp conformation, play a crucial role for the solvolytic and catalytic effects exerted by HFIP, rather than monomers.
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Affiliation(s)
- Albrecht Berkessel
- Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, D-50939 Köln, Germany.
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116
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Abstract
New chiral catalyst systems were developed for the reaction of carbon dioxide with propylene oxide (PO) at atmospheric pressure to generate enantiomerically enriched propylene carbonate (PC). The best selectivity was achieved with a Co(III)(salen)-trifluoroacetyl complex and bis(triphenylphosphoranylidene)ammonium fluoride (PPN+F-) as catalysts, affording PC in 40% yield and 83% ee (selectivity factor = 19). In addition, PC was prepared for the first time by kinetic resolution of PO with tetrabutylammonium methyl carbonate (TBAMC, nBu4N+ (-)OOCOMe). With TBAMC as "activated CO2", up to 71% ee was obtained.
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Affiliation(s)
- Albrecht Berkessel
- Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, D-50939 Köln, Germany.
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117
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Berkessel A, Guixà M, Schmidt F, Neudörfl JM, Lex J. Highly Enantioselective Epoxidation of 2-Methylnaphthoquinone (Vitamin K3) Mediated by NewCinchona Alkaloid Phase-Transfer Catalysts. Chemistry 2007; 13:4483-98. [PMID: 17348045 DOI: 10.1002/chem.200600993] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In the area of catalytic asymmetric epoxidation, the highly enantioselective transformation of cyclic enones and quinones is an extremely challenging target. With the aim to develop new and highly effective phase-transfer catalysts for this purpose, we conducted a systematic structural variation of PTCs based on quinine and quinidine. In the total of 15 new quaternary ammonium PTCs, modifications included, for example, the exchange of the quinine methoxy group for a free hydroxyl or other alkoxy substituents, and the introduction of additional elements of chirality through alkylation of the alkaloid quinuclidine nitrogen atom by chiral electrophiles. For example, the well-established 9- anthracenylmethyl group was exchanged for a "chiral" anthracene in the form of 9-chloromethyl-[(1,8-S;4,5-R)-1,2,3,4,5,6,7,8-octahydro-1,4:5,8-dimethanoanthracene. The asymmetric epoxidation of vitamin K(3) was used as the test reaction for our novel PTCs. The readily available PTC 10 (derived from quinine in three convenient and high-yielding steps) proved to be the most enantioselective catalyst for this purpose known to date: At a catalyst loading of only 2.50 mol %, the quinone epoxide was obtained in 76 % yield and with 85 % ee (previously: < or =34 % ee), using commercial bleach (aqueous sodium hypochlorite) as the oxidant. To rationalize the sense of induction effected by our novel phase-transfer catalysts, a computational analysis of steric interactions in the intermediate chlorooxy enolate-PTC ion pair was conducted. Based on this analysis, the sense of induction for all 15 novel PTCs could be consistently explained.
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Affiliation(s)
- Albrecht Berkessel
- Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, 50393 Köln, Germany.
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118
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Sachinidis A, Schwengberg S, Hippler-Altenburg R, Mariappan D, Kamisetti N, Seelig B, Berkessel A, Hescheler J. Identification of small signalling molecules promoting cardiac-specific differentiation of mouse embryonic stem cells. Cell Physiol Biochem 2007; 18:303-14. [PMID: 17170517 DOI: 10.1159/000097608] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2006] [Indexed: 12/14/2022] Open
Abstract
Identification of signalling cascades involved in cardiomyogenesis is crucial for optimising the generation of cardiomyocytes from embryonic stem cells (ES cells) (in vitro). We used a transgenic ES cell lineage expressing enhanced green fluorescent protein (EGFP) under the control of the alpha-myosin heavy chain (alpha-MHC) promoter (palphaMHC-EGFP) to investigate the effects of 33 small molecules interfering with several signalling cascades on cardiomyogenesis. Interestingly, the L-Type Ca2+ channel blocker Verapamil as well as Cyclosporin, an inhibitor of the protein phosphatase 2B, exerted the most striking pro-cardiomyogenic effect. Forskolin (adenylate cyclase stimulator) exerted the most striking anti-cardiomyogenic effect. The cardiomyogenic effect of Cyclosporin and Verapamil correlated with an expression of early cardiac markers Nkx2.5 and GATA4. Compared to the effects on late developmental stage embryoid bodies (EBs) stimulation of early developmental stage EBs (1-day old) with Verapamil or Cyclosporin for 48 h resulted in a potent cardiomyogenic effect. Accordingly, enhanced expression of alpha-MHC mRNA and EGFP mRNA was observed after stimulation of the early developmental stage EBs for 48 h. No expression of alpha-smooth muscle actin or platelet endothelial cell adhesion molecule-1 (PECM-1) as well as of neuronal genes (Nestin, Neurofilament H) has been observed demonstrating a preferentially pro-cardiomyogenic effect by both molecules.
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Affiliation(s)
- Agapios Sachinidis
- Centre of Physiology and Pathophysiology, Institute of Neurophysiology, Cologne, Germany.
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119
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Berkessel A. Organocatalysis by hydrogen bonding networks. Ernst Schering Found Symp Proc 2007; 40:281-297. [PMID: 18642529 DOI: 10.1002/chin.200933252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In biological systems, hydrogen bonding is used extensively for molecular recognition, substrate binding, orientation and activation. In organocatalysis, multiple hydrogen bonding by man-made catalysts can effect remarkable accelerations and selectivities as well. The lecture presents four examples of non-enzymatic (but in some cases enzyme-like!) catalysis effected by hydrogen bonding networks: epoxidation of olefins and Baeyer-Villiger oxidation of ketones with H2O2 in fluorinated alcohol solvents; peptide-catalyzed asymmetric epoxidation of enones by H2O2; dynamic kinetic resolution of azlactones, affording enantiomerically pure alpha-amino acids; and kinetic resolution of oxazinones, affording enantiomerically pure beta-amino acids. All four types of transformations are of preparative value, and their mechanisms are discussed.
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Affiliation(s)
- A Berkessel
- Department of Chemistry, University of Cologne, Cologne, Germany.
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120
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Abstract
Tetraarylporphyrin ruthenium complexes [Ru(L)(aryl(4)Por)] (L = CO or PF(3); aryl = mesityl or 10-R'-bis-methano-octahydroanthracene-9-yl with R' = H, CF(3), OCH(3) or CH(3)) show a rich electrochemistry with at least five different stable oxidation states (including the parent state). The overall character of the redox behaviour is porphyrin-centred. However detailed spectroelectrochemical investigations using IR, UV/Vis/NIR and EPR spectroscopy (X- and K band) gave clear indication for ruthenium contributions.
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Affiliation(s)
- Albrecht Berkessel
- Universität zu Köln, Institut für Organische Chemie, Greinstrasse 4, D-50939, Köln, Germany.
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121
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Berkessel A, Ertürk E. Hydrolytic Kinetic Resolution of Epoxides Catalyzed by Chromium(III)-endo,endo-2,5-diaminonorbornane-salen [Cr(III)-DIANANE-salen] Complexes. Improved Activity, Low Catalyst Loading. Adv Synth Catal 2006. [DOI: 10.1002/adsc.200606181] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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122
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Berkessel A, Roland K, Schröder M, Neudörfl JM, Lex J. Enantiomerically Pure Isophorone Diamine [3-(Aminomethyl)-3,5,5-trimethylcyclohexylamine]: A Chiral 1,4-Diamine Building Block Made Available on Large Scale. J Org Chem 2006; 71:9312-8. [PMID: 17137357 DOI: 10.1021/jo0613737] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Isophorone diamine [IPDA, 3-(aminomethyl)-3,5,5-trimethylcyclohexylamine] is a chiral non-C2-symmetric 1,4-diamine which is produced industrially on large scale as the mixture of all four stereoisomers (cis/trans ca. 3:1). Starting from this industrial bulk product, the preparation of the bis-tosyl, bis-Fmoc, bis-Boc and bis-Z derivatives of cis-IPDA, the preparation of the pure cis enantiomers by HPLC on chiral stationary phase, and the assignment of absolute configurations to the isolated enantiomers are described. We furthermore report an efficient method for the optical resolution of IPDA by salt formation with dibenzoyl tartaric acid. The latter method conveniently affords enantiomerically pure cis-IPDA in 100 g quantities. A number of salen ligands have been prepared from this enantiomerically pure 1,4-diamine and fully characterized. The nickel complex of one of the salen ligands was prepared and analyzed by X-ray crystallography. The crystal structure of the Ni4L4 complex illustrates the pronounced preference of cis-IPDA for adopting the chair conformation in which both the amino- and the aminomethyl substituents occupy equatorial positions. As a consequence, the two salicylidene imine moieties of one ligand molecule do not converge on one metal ion, but act as bridging ligands between two nickel ions.
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Affiliation(s)
- Albrecht Berkessel
- Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, D-50939 Köln, Germany.
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123
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Berkessel A, Vogl N. DIANANE-CrIII-salen Complexes as Highly Enantioselective Catalysts for Hetero-Diels–Alder Reactions of Aldehydes with Dienes. European J Org Chem 2006. [DOI: 10.1002/ejoc.200600359] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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124
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Berkessel A, Sebastian-Ibarz ML, Müller TN. Lipase/Aluminium-katalysierte dynamische kinetische Racematspaltung von sekundären Alkoholen. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200600379] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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125
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Affiliation(s)
- Albrecht Berkessel
- Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, 50939 Köln, Germany.
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126
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Abstract
The ability of microemulsions to dissolve polar and non-polar components with a huge internal interface can overcome the reagent incompatibilities frequently encountered in organic reactions. We investigated model epoxidation reactions of alpha,beta-unsaturated enones and alkaline hydrogen peroxide in different nonionic microemulsions, both in the presence and absence of a phase-transfer agent (PTA). The obtained reaction profiles were compared with those for the corresponding surfactant-free two-phase systems. In addition, we defined a time constant tau as a measure for the rate of turnover. The epoxidation of trans-chalcone using an n-alkyl-polyoxyethylene surfactant based microemulsion was fastest in the system with the PTA (tau=66 min) and slightly slower without the PTA (tau=77 min). It was still slower in the two-phase system with a PTA (tau=114 min) and extremely sluggish without a phase-transfer agent. With n-alkyl beta-D-glucopyranoside as the surfactant the conversion was twice as fast than in the former microemulsion systems, but the PTA did not accelerate the reaction further (tau=35 and 33 min). The epoxidation of vitamin K(3), the second model system, was extremely accelerated. It proceeded a factor of approximately 35 faster in the microemulsion (tau=1.44 min) than in the corresponding two-phase system (tau=57 min).
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Affiliation(s)
- Thomas Wielpütz
- Department of Physical Chemistry, University of Cologne Luxemburger Strasse 116, 50939 Köln, Germany
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127
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Wielpütz T, Sottmann T, Strey R, Schmidt F, Berkessel A. Cover Picture: Dramatic Enhancement of Enone Epoxidation Rates in Nonionic Microemulsions (Chem. Eur. J. 29/2006). Chemistry 2006. [DOI: 10.1002/chem.200690092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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128
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Berkessel A, Adrio JA. Dramatic Acceleration of Olefin Epoxidation in Fluorinated Alcohols: Activation of Hydrogen Peroxide by Multiple H-Bond Networks. J Am Chem Soc 2006; 128:13412-20. [PMID: 17031953 DOI: 10.1021/ja0620181] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as solvent, the epoxidation of olefins by hydrogen peroxide is accelerated up to ca. 100 000-fold (relative to that in 1,4-dioxane as solvent). The mechanistic basis of this effect was investigated kinetically and theoretically. The kinetics of the epoxidation of Z-cyclooctene provided evidence that higher-order solvent aggregates (rate order in HFIP ca. 3) are responsible for the rate acceleration. Activation parameters (DeltaS++ = -39 cal/mol.K) indicated a highly ordered transition state in the rate-determining step. In line with these findings, DFT simulations revealed a pronounced decrease of the activation barrier for oxygen transfer from H(2)O(2) to ethene with increasing number of (specifically) coordinated HFIP molecules. The oxygen transfer was unambiguously identified as a polar concerted process. Simulations (combined DFT and MP2) of the epoxidation of Z-butene were in excellent agreement with the experimental data obtained in the epoxidation of Z-cyclooctene (activation enthalpy, entropy, and kinetic rate order in HFIP of 3), supporting the validity of our mechanistic model.
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Affiliation(s)
- Albrecht Berkessel
- Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, D-50939 Köln, Germany.
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129
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Berkessel A, Roland K, Neudörfl JM. Asymmetric Morita−Baylis−Hillman Reaction Catalyzed by Isophoronediamine-Derived Bis(thio)urea Organocatalysts. Org Lett 2006; 8:4195-8. [PMID: 16956185 DOI: 10.1021/ol061298m] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
New and improved bis(thio)urea catalysts were synthesized from isophoronediamine (IPDA) and tested in the Morita-Baylis-Hillman reaction. The best results were achieved in the reaction of 2-cyclohexen-1-one with cyclohexanecarbaldehyde, using the catalyst depicted above, in combination with a novel base (N,N,N',N'-tetramethylisophoronediamine, TMIPDA) in toluene. The desired Morita-Baylis-Hillman product was obtained in 75% yield and 96% ee.
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Affiliation(s)
- Albrecht Berkessel
- Institute for Organic Chemistry, University of Cologne, Greinstrasse 4, 50939 Cologne, Germany.
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130
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Koch B, Toma S, Berkessel A, Meciarova M. Enantioselective Aldol Reactions Catalysed by N-Toluenesulfonyl-L-proline Amide in Ionic Liquids. LETT ORG CHEM 2006. [DOI: 10.2174/157017806777828402] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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131
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Paterson I, Bergmann H, Menche D, Berkessel A. Synthesis of Novel 11-Desmethyl Analogues of Laulimalide by Nozaki−Kishi Coupling. Org Lett 2006. [DOI: 10.1021/ol060252q] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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132
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Fuhr U, Boettcher MI, Kinzig-Schippers M, Weyer A, Jetter A, Lazar A, Taubert D, Tomalik-Scharte D, Pournara P, Jakob V, Harlfinger S, Klaassen T, Berkessel A, Angerer J, Sörgel F, Schömig E. Toxicokinetics of Acrylamide in Humans after Ingestion of a Defined Dose in a Test Meal to Improve Risk Assessment for Acrylamide Carcinogenicity. Cancer Epidemiol Biomarkers Prev 2006; 15:266-71. [PMID: 16492914 DOI: 10.1158/1055-9965.epi-05-0647] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
High amounts of acrylamide in some foods result in an estimated daily mean intake of 50 microg for a western style diet. Animal studies have shown the carcinogenicity of acrylamide upon oral exposure. However, only sparse human toxicokinetic data is available for acrylamide, which is needed for the extrapolation of human cancer risk from animal data. We evaluated the toxicokinetics of acrylamide in six young healthy volunteers after the consumption of a meal containing 0.94 mg of acrylamide. Urine was collected up to 72 hours thereafter. Unchanged acrylamide, its mercapturic acid metabolite N-acetyl-S-(2-carbamoylethyl)cysteine (AAMA), its epoxy derivative glycidamide, and the respective metabolite of glycidamide, N-acetyl-S-(2-hydroxy-2-carbamoylethyl)cysteine (GAMA), were quantified in the urine by liquid chromatography-mass spectrometry. Toxicokinetic variables were obtained by noncompartmental methods. Overall, 60.3 +/- 11.2% of the dose was recovered in the urine. Although no glycidamide was found, unchanged acrylamide, AAMA, and GAMA accounted for urinary excretion of (mean +/- SD) 4.4 +/- 1.5%, 50.0 +/- 9.4%, and 5.9 +/- 1.2% of the dose, respectively. Apparent terminal elimination half-lives for the substances were 2.4 +/- 0.4, 17.4 +/- 3.9, and 25.1 +/- 6.4 hours. The ratio of GAMA/AAMA amounts excreted was 0.12 +/- 0.02. In conclusion, most of the acrylamide ingested with food is absorbed in humans. Conjugation with glutathione exceeds the formation of the reactive metabolite glycidamide. The data suggests an at least 2-fold and 4-fold lower relative internal exposure for glycidamide from dietary acrylamide in humans compared with rats or mice, respectively. This should be considered for quantitative cancer risk assessment.
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Affiliation(s)
- Uwe Fuhr
- Department of Pharmacology, University Hospital, University of Cologne, Gleueler Strasse 24, 50931 Cologne, Germany.
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133
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Affiliation(s)
- Albrecht Berkessel
- Institut für Organische Chemie der Johann‐Wolfgang‐Goethe‐Universität, Niederurseler Hang, D‐6000 Frankfurt/Main 50
| | - Markus Voges
- Institut für Organische Chemie der Johann‐Wolfgang‐Goethe‐Universität, Niederurseler Hang, D‐6000 Frankfurt/Main 50
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134
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Berkessel A, Ertürk E, Laporte C. Chiral Chromium(III) Porphyrins as Highly Enantioselective Catalysts for Hetero-Diels–Alder Reactions Between Aldehydes and Dienes. Adv Synth Catal 2006. [DOI: 10.1002/adsc.200505249] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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135
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Berkessel A, Mukherjee S, Lex J. Reversal of Enantioselectivity by Catalyst Protonation: Asymmetric Hydrocyanation of Imines with Oxazaborolidines. Synlett 2006. [DOI: 10.1055/s-2005-922757] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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136
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137
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Berkessel A, Mukherjee S, Müller TN, Cleemann F, Roland K, Brandenburg M, Neudörfl JM, Lex J. Structural optimization of thiourea-based bifunctional organocatalysts for the highly enantioselective dynamic kinetic resolution of azlactones. Org Biomol Chem 2006; 4:4319-30. [PMID: 17102877 DOI: 10.1039/b607574f] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This article describes the synthesis of a library of structurally diverse bifunctional organocatalysts bearing both a quasi-Lewis acidic (thio)urea moiety and a Brønsted basic tertiary amine group. Sequential modification of the modular catalyst structure and subsequent screening of the compounds in the alcoholytic dynamic kinetic resolution (DKR) of azlactones revealed valuable structure-activity relationships. In particular, a "hit-structure" was identified which provides e.g.N-benzoyl-tert-leucine allyl ester in an excellent enantiomeric excess of 95%.
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Affiliation(s)
- Albrecht Berkessel
- Institut für Organische Chemie der Universität zu Köln, Greinstrasse 4, D-50939 Köln, Germany.
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138
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Berkessel A, Koch B, Toniolo C, Rainaldi M, Broxterman QB, Kaptein B. Asymmetric enone epoxidation by short solid-phase bound peptides: Further evidence for catalyst helicity and catalytic activity of individual peptide strands. Biopolymers 2006; 84:90-6. [PMID: 16283656 DOI: 10.1002/bip.20413] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In the presence of short solid-phase bound peptide catalysts, the Juliá-Colonna epoxidation of enones (such as chalcone) with hydrogen peroxide can be performed with high enantiomeric excess (> or = 95% ee). It was proposed earlier (A. Berkessel, N. Gasch, K. Glaubitz, C. Koch, Organic Letters, 2001, Vol. 3, pp. 3839-3842) that this remarkable catalysis is governed by the N-terminus of individual and helical peptide strands. This mechanistic proposal was scrutinized further. (i) Nonaggregation of the peptide catalysts: five solid-phase bound statistic mixtures (0/100; 30/70; 50/50; 70/30; 100/0) of D-Leu and L-Leu heptamers were generated and assayed as catalysts. A linear dependence of the epoxide ee on the enantiomeric composition of the catalysts resulted. (ii) Catalyst helicity [introduction of the helix-stabilizing C(alpha)-methyl-L-leucine, L-(alphaMe)Leu]: solid-phase bound Leu/(alphaMe)Leu-pentamers of composition TentaGel-NH-[(alphaMe)-L-Leu]n-(L-Leu)m-H (n = 0-4; m = 5-n) were prepared and assayed as catalysts. The introduction of up to two (alphaMe)-L-Leu residues (n = 1, 2) significantly enhanced the catalyst activity relative to the L-Leu homopentamer (n = 0). Higher (alphaMe)-L-Leu contents (n = 3, 4) led to a decrease in both catalyst activity and enantiopurity of the product epoxide. In summary, both the individual catalytic action of the peptide strands and the helical conformation as the catalytically competent state of the peptide catalysts were further supported.
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Affiliation(s)
- Albrecht Berkessel
- Institute of Organic Chemistry, University of Köln, D-50939 Köln, Germany.
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139
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Berkessel A, Cleemann F, Mukherjee S. Kinetic Resolution of Oxazinones: An Organocatalytic Approach to Enantiomerically Pure β-Amino Acids. Angew Chem Int Ed Engl 2005; 44:7466-9. [PMID: 16245379 DOI: 10.1002/anie.200502003] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Albrecht Berkessel
- Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, 50-939 Köln, Germany.
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140
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Berkessel A, Cleemann F, Mukherjee S. Kinetische Racematspaltung von Oxazinonen - ein organokatalytischer Zugang zu enantiomerenreinen β-Aminosäuren. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200502003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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141
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142
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Abstract
As a first entry into structurally simplified analogues of the anticancer agent laulimalide, 11-desmethyl compounds 2 and 3 were selected by molecular modeling. The unfavorable diastereoselectivity in the key synthetic step, a Nozaki-Kishi coupling between macrocyclic aldehyde 4 and vinyl iodide 5, was overcome either by use of catalytic amounts of DIANANE-type ligands or L-Selectride reduction of the derived enone. This methodology should allow modular introduction of other, unnatural, side chains. [reaction: see text]
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Affiliation(s)
- Ian Paterson
- University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, U.K.
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143
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Berkessel A, Cleemann F, Mukherjee S, Müller TN, Lex J. Cover Picture: Highly Efficient Dynamic Kinetic Resolution of Azlactones by Urea-Based Bifunctional Organocatalysts (Angew. Chem. Int. Ed. 5/2005). Angew Chem Int Ed Engl 2005. [DOI: 10.1002/anie.200590014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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144
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Berkessel A, Cleemann F, Mukherjee S, Müller TN, Lex J. Titelbild: Bifunktionale Organokatalysatoren auf Harnstoff-Basis für die effiziente dynamische kinetische Racemattrennung von Azlactonen (Angew. Chem. 5/2005). Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200590014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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145
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Berkessel A, Cleemann F, Mukherjee S, Müller TN, Lex J. Bifunktionale Organokatalysatoren auf Harnstoff-Basis für die effiziente dynamische kinetische Racemattrennung von Azlactonen. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200461442] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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146
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Berkessel A, Cleemann F, Mukherjee S, Müller TN, Lex J. Highly Efficient Dynamic Kinetic Resolution of Azlactones by Urea-Based Bifunctional Organocatalysts. Angew Chem Int Ed Engl 2005; 44:807-11. [PMID: 15657971 DOI: 10.1002/anie.200461442] [Citation(s) in RCA: 236] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Albrecht Berkessel
- Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, 50939 Köln, Germany.
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147
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Berkessel A, Mukherjee S, Cleemann F, Muller TN, Lex J. Second-generation organocatalysts for the highly enantioselective dynamic kinetic resolution of azlactones. Chem Commun (Camb) 2005:1898-900. [PMID: 15795780 DOI: 10.1039/b418666d] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bifunctional organocatalysts of the thiourea-tert-amine type, carrying two "matched" elements of chirality, effect the alcoholytic dynamic kinetic resolution of a variety of azlactones with up to 95% ee.
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Affiliation(s)
- Albrecht Berkessel
- Institut fur Organische Chemie der Universitat zu Koln, Greinstrasse 4, D-50939, Koln, Germany.
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148
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Abstract
The copper enzyme galactose oxidase (GOase, EC 1.1.3.9) catalyses the oxidation of D-galactose and other primary alcohols in air to the corresponding aldehydes and hydrogen peroxide. The current mechanistic hypothesis for this two-electron redox reaction involves a Cu(I)/Cu(II) couple and the reversible oxidation of a ligating phenolate (tyrosine residue of the Tyr272-Cys228 conjugate) to a phenoxyl radical. Our approaches to functional models for galactose oxidase comprise both the use of low-molecular-weight copper complexes of a Schiff-base and sulfonamide ligands, and the synthesis/screening of combinatorial libraries. With regard to the latter, we have synthesized (by the IRORI-directed synthesis approach) peptide libraries carrying either His or the redox-active amino acids Tyr, mod-Cys (a model for the Tyr272-Cys228 conjugate) or TOAC (a TEMPO-derived alpha-amino acid) at four variable positions. After incubation with copper ions, the catalytically active library members were identified by specially designed screening methods.
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Affiliation(s)
- Albrecht Berkessel
- Institut für Organische Chemie der Universität zu Köln, Greinstrasse 4, D-50939 Köln, Germany.
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149
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Berkessel A, Koch B, Lex J. Proline-DerivedN-Sulfonylcarboxamides: Readily Available, Highly Enantioselective and Versatile Catalysts for Direct Aldol Reactions. Adv Synth Catal 2004. [DOI: 10.1002/adsc.200404126] [Citation(s) in RCA: 195] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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150
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Berkessel A, Schröder M, Sklorz CA, Tabanella S, Vogl N, Lex J, Neudörfl JM. Enantioselective Synthesis of DIANANE, a Novel C2-Symmetric Chiral Diamine for Asymmetric Catalysis. J Org Chem 2004; 69:3050-6. [PMID: 15104443 DOI: 10.1021/jo035841d] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
DIANANE (endo,endo-2,5-diaminonorbornane) is a novel chiral C(2)-symmetric diamine, based on the rigid bicyclo[2.2.1]heptane scaffold. Schiff-base ligands derived from DIANANE have already found use in asymmetric catalysis, e.g., in the highly enantioselective Nozaki-Hiyama-Kishi reaction. We herein describe a practical synthesis of enantiomerically pure DIANANE, starting from norbornadiene in four steps: (i) Pd-MOP catalyzed Hayashi-hydrosilylation/Tamao-Fleming oxidation, (ii) oxidation to norbornane-2,5-dione, (iii) endo-selective reductive amination with benzylamine, and (iv) hydrogenolytic debenzylation. None of the steps involves chromatographic purification. For the Tamao-Fleming oxidation, the use of hydrogen peroxide in the form of its urea clathrate instead of aqueous solution proved beneficial. By the above sequence, enantiomerically pure (ee >or=99%) DIANANE was obtained from norbornadiene in 40-50% overall yield. The relative and absolute configuration of DIANANE was confirmed by X-ray crystallography of the DIANANE bis-tosylamide, and of its bis-camphorsulfonamide. Furthermore, the synthesis and X-ray crystal structure of the Schiff-base ligand derived from DIANANE and 3,5-di-tert-butyl salicylic aldehyde are reported.
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Affiliation(s)
- Albrecht Berkessel
- Institut für Organische Chemie, Universität zu Köln, Greinstrasse 4, D-50939 Köln, Germany.
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