1451
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Ito K, Nishida K, Gotanda T. Highly enantioselective aza-Morita–Baylis–Hillman reaction with a bisphenol-based bifunctional organocatalyst. Tetrahedron Lett 2007. [DOI: 10.1016/j.tetlet.2007.06.158] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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1452
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Hamilton GL, Kang EJ, Mba M, Toste FD. A Powerful Chiral Counterion Strategy for Asymmetric Transition Metal Catalysis. Science 2007; 317:496-9. [PMID: 17656720 DOI: 10.1126/science.1145229] [Citation(s) in RCA: 733] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Traditionally, transition metal-catalyzed enantioselective transformations rely on chiral ligands tightly bound to the metal to induce asymmetric product distributions. Here we report high enantioselectivities conferred by a chiral counterion in a metal-catalyzed reaction. Two different transformations catalyzed by cationic gold(I) complexes generated products in 90 to 99% enantiomeric excess with the use of chiral binaphthol-derived phosphate anions. Furthermore, we show that the chiral counterion can be combined additively with chiral ligands to enable an asymmetric transformation that cannot be achieved by either method alone. This concept of relaying chiral information via an ion pair should be applicable to a vast number of metal-mediated processes.
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Affiliation(s)
- Gregory L Hamilton
- Department of Chemistry, University of California at Berkeley, Berkeley, CA 94720, USA
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1453
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Alemán J, Richter B, Jørgensen K. Organocatalytic Highly Enantioselective α-Arylation of β-Ketoesters. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200701009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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1454
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Alemán J, Richter B, Jørgensen KA. Organocatalytic Highly Enantioselective α-Arylation of β-Ketoesters. Angew Chem Int Ed Engl 2007; 46:5515-9. [PMID: 17523204 DOI: 10.1002/anie.200701009] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- José Alemán
- Danish National Research Foundation, Center for Catalysis Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark
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1455
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Gu LQ, Zhao G. 4,4′-Disubstituted-L-proline Catalyzes the Direct Asymmetric Michael Addition of Aldehydes to Nitrostyrenes. Adv Synth Catal 2007. [DOI: 10.1002/adsc.200600640] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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1456
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You SL. Recent Developments in Asymmetric Transfer Hydrogenation with Hantzsch Esters: A Biomimetic Approach. Chem Asian J 2007; 2:820-7. [PMID: 17551915 DOI: 10.1002/asia.200700081] [Citation(s) in RCA: 265] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
By utilizing Hantzsch esters as the hydrogen source, asymmetric transfer hydrogenation of C=C, C=N, and C=O is realized in the presence of an organocatalyst or a metal-ligand complex, thus affording versatile chiral building blocks in high yields with excellent enantioselectivities under mild conditions. A detailed discussion of recent findings and an assessment of this biomimetic approach are presented in this review.
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Affiliation(s)
- Shu-Li You
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China.
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1457
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Roussel C, Roman M, Andreoli F, Del Rio A, Faure R, Vanthuyne N. Non-racemic atropisomeric (thio)ureas as neutral enantioselective anion receptors for amino-acid derivatives: origin of smaller Kass with thiourea than urea derivatives. Chirality 2007; 18:762-71. [PMID: 16871519 DOI: 10.1002/chir.20320] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The synthesis of a limited series of non-racemic atropisomeric 1-(2-(4-methyl-2-thioxothiazol-3(2H)-yl)phenyl)-3-(hetero)aryl-(thio)ureas is described. Using NMR titration experiments monitoring the shift of the two NH of the (thio)urea and the C-5 hydrogen of the heterocycle, the binding constants for some optically pure (thio)-ureas with the enantiomers of N-protected amino acid tetrabutylammonium salts were determined in CD3CN. The obtained enantioselectivities were modest. Contrary to what was expected on the basis of the NH acidity in thiourea versus urea group, the association constants were smaller with the thiourea than with the corresponding urea. X-ray data, DFT calculations, and NMR provided the explanation of that unexpected behavior: the urea presents a pre-organized (Z,Z) conformation suitable for a double hydrogen bond with the carboxylate anion, the thiourea presents a (Z,E) conformation, which must be reorganized in a constrained (Z,Z) conformation in the complex. An intramolecular hydrogen bond between one NH and the thiocarbonyl group of the heterocycle, which is present in the thiourea and absent in the urea, might also contribute to the smaller K(ass) for the thiourea. The possible implication of these observations in the field of bifunctional organocatalysis is briefly discussed.
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Affiliation(s)
- Christian Roussel
- Laboratoire Stéréochimie dynamique et Chiralité, UMR 6180, Chirotechnologies, catalyse et biocatalyse, CNRS-Université Paul Cézanne-Aix-Marseille III, Marseille, France.
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1458
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Jensen K, Sigman M. Systematically Probing the Effect of Catalyst Acidity in a Hydrogen-Bond-Catalyzed Enantioselective Reaction. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200700298] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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1459
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Masson G, Housseman C, Zhu J. Enantioselektive Morita-Baylis-Hillman-Reaktionen und ihre Aza-Varianten. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200604366] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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1460
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Jensen KH, Sigman MS. Systematically Probing the Effect of Catalyst Acidity in a Hydrogen-Bond-Catalyzed Enantioselective Reaction. Angew Chem Int Ed Engl 2007; 46:4748-50. [PMID: 17503406 DOI: 10.1002/anie.200700298] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Katrina H Jensen
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, USA
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1461
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Sibi MP, Itoh K. Organocatalysis in Conjugate Amine Additions. Synthesis of β-Amino Acid Derivatives. J Am Chem Soc 2007; 129:8064-5. [PMID: 17552527 DOI: 10.1021/ja071739c] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mukund P Sibi
- Department of Chemistry, North Dakota State University, Fargo, ND 58105, USA.
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1462
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Revell JD, Wennemers H. Peptidic catalysts developed by combinatorial screening methods. Curr Opin Chem Biol 2007; 11:269-78. [PMID: 17548237 DOI: 10.1016/j.cbpa.2007.05.015] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Accepted: 05/17/2007] [Indexed: 11/25/2022]
Abstract
In recent years, oligopeptides have been developed as efficient catalysts for a range of important organic reactions, including acylation, silylation, oxidation, ester hydrolysis and aldol reactions. With many peptidic catalysts, high yields and chiral induction can be achieved under mild reaction conditions. Discovery and optimization of these catalysts typically involves the testing of compound collections and is therefore strongly linked to advances in combinatorial screening methods. This review summarizes recent developments in the field of catalytically active short-chain peptides, highlighting the combinatorial techniques that have facilitated their discovery.
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Affiliation(s)
- Jefferson D Revell
- Department of Chemistry, University of Basel, St Johanns-Ring 19, CH-4056 Basel, Switzerland
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1463
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Jiang L, Zheng HT, Liu TY, Yue L, Chen YC. Asymmetric direct vinylogous carbon–carbon bond formation catalyzed by bifunctional organocatalysts. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.04.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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1464
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Walsh PJ, Li H, de Parrodi CA. A green chemistry approach to asymmetric catalysis: solvent-free and highly concentrated reactions. Chem Rev 2007; 107:2503-45. [PMID: 17530908 PMCID: PMC2525622 DOI: 10.1021/cr0509556] [Citation(s) in RCA: 289] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Patrick J. Walsh
- P. Roy and Diana T. Vagelos Laboratories, University of Pennsylvania, Department of Chemistry, 231 South 34 Street, Philadelphia, Pennsylvania 19104-6323
| | - Hongmei Li
- P. Roy and Diana T. Vagelos Laboratories, University of Pennsylvania, Department of Chemistry, 231 South 34 Street, Philadelphia, Pennsylvania 19104-6323
| | - Cecilia Anaya de Parrodi
- Universidad de las Américas-Puebla, Departamento de Ciencias Químico Biológicas, Santa Catarina Mártir s/n, Cholula Puebla, 72820, México
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1465
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Guillena G, del Carmen Hita M, Nájera C. α-Chloroacetone as a donor in the BINAM-l-prolinamide organocatalyzed aldol reaction: application to the enantioselective synthesis of α,β-epoxy ketones. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.tetasy.2007.05.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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1466
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Zhou J, List B. Organocatalytic Asymmetric Reaction Cascade to Substituted Cyclohexylamines. J Am Chem Soc 2007; 129:7498-9. [PMID: 17530851 DOI: 10.1021/ja072134j] [Citation(s) in RCA: 249] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jian Zhou
- Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim an der Ruhr, Germany
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1467
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Jang HY, Hong JB, MacMillan DWC. Enantioselective Organocatalytic Singly Occupied Molecular Orbital Activation: The Enantioselective α-Enolation of Aldehydes. J Am Chem Soc 2007; 129:7004-5. [PMID: 17497866 DOI: 10.1021/ja0719428] [Citation(s) in RCA: 256] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hye-Young Jang
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, USA
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1468
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Palomo C, Oiarbide M, Laso A. Recent Advances in the Catalytic Asymmetric Nitroaldol (Henry) Reaction. European J Org Chem 2007. [DOI: 10.1002/ejoc.200700021] [Citation(s) in RCA: 437] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Claudio Palomo
- Departamento de Química Orgánica I, Facultad de Química, Universidad del País Vasco, Apdo. 1072, 20080 San Sebastián, Spain, Fax: +34‐943015270
| | - Mikel Oiarbide
- Departamento de Química Orgánica I, Facultad de Química, Universidad del País Vasco, Apdo. 1072, 20080 San Sebastián, Spain, Fax: +34‐943015270
| | - Antonio Laso
- Departamento de Química Orgánica I, Facultad de Química, Universidad del País Vasco, Apdo. 1072, 20080 San Sebastián, Spain, Fax: +34‐943015270
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1469
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Wang J, Heikkinen L, Li H, Zu L, Jiang W, Xie H, Wang W. Quinine-Catalyzed Enantioselective Michael Addition of Diphenyl Phosphite to Nitroolefins: Synthesis of Chiral Precursors of α-Substituted β-Aminophosphonates. Adv Synth Catal 2007. [DOI: 10.1002/adsc.200600429] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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1470
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Cao CL, Sun XL, Zhou JL, Tang Y. Enantioselectively Organocatalytic Michael Addition of Ketones to Alkylidene Malonates. J Org Chem 2007; 72:4073-6. [PMID: 17474778 DOI: 10.1021/jo070070p] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An organocatalytic asymmetric Michael addition of ketones to alkylidene malonates has been developed. In the presence of 20 mol % of urea 1a or N-(pyrrolidin-2-ylmethyl)trifluoromethanesulfonamide 1j, the reactions of ketones with alkylidene malonates afford the desired Michael adducts in moderate to good yields with good to high enantioselectivities under mild conditions.
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Affiliation(s)
- Chun-Li Cao
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, People's Republic of China
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1471
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Wang Y, Li H, Wang YQ, Liu Y, Foxman BM, Deng L. Asymmetric Diels-Alder reactions of 2-pyrones with a bifunctional organic catalyst. J Am Chem Soc 2007; 129:6364-5. [PMID: 17469829 PMCID: PMC3172003 DOI: 10.1021/ja070859h] [Citation(s) in RCA: 195] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yi Wang
- Department of Chemistry, Brandeis University, Waltham, MA 02454-9110, USA
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1472
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Beeson TD, Mastracchio A, Hong JB, Ashton K, Macmillan DWC. Enantioselective Organocatalysis Using SOMO Activation. Science 2007; 316:582-5. [PMID: 17395791 DOI: 10.1126/science.1142696] [Citation(s) in RCA: 525] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The asymmetric α-addition of relatively nonpolar hydrocarbon substrates, such as allyl and aryl groups, to aldehydes and ketones remains a largely unsolved problem in organic synthesis, despite the wide potential utility of direct routes to such products. We reasoned that well-established chiral amine catalysis, which activates aldehydes toward electrophile addition by enamine formation, could be expanded to this important reaction class by applying a single-electron oxidant to create a transient radical species from the enamine. We demonstrated the concept of singly occupied molecular orbital (SOMO) activation with a highly selective α-allylation of aldehydes, and we here present preliminary results for enantioselective heteroarylations and cyclization/halogenation cascades.
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Affiliation(s)
- Teresa D Beeson
- Merck Center for Catalysis, Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
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1473
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Tan KL, Jacobsen EN. Indium-mediated asymmetric allylation of acylhydrazones using a chiral urea catalyst. Angew Chem Int Ed Engl 2007; 46:1315-7. [PMID: 17211916 DOI: 10.1002/anie.200603354] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kian L Tan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
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1474
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Movassaghi M, Chen B. Stereoselective intermolecular formal [3+3] cycloaddition reaction of cyclic enamines and enones. Angew Chem Int Ed Engl 2007; 46:565-8. [PMID: 17146819 PMCID: PMC3510678 DOI: 10.1002/anie.200603302] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Mohammad Movassaghi
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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1475
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Friberg A, Olsson C, Ek F, Berg U, Frejd T. Cleft molecules as organocatalysts in an asymmetric hetero-Diels–Alder reaction. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.tetasy.2007.03.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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1476
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1477
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Sakakura A, Suzuki K, Nakano K, Ishihara K. Chiral 1,1'-binaphthyl-2,2'-diammonium salt catalysts for the enantioselective Diels-Alder reaction with alpha-acyloxyacroleins. Org Lett 2007; 8:2229-32. [PMID: 16706493 DOI: 10.1021/ol060490l] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] A diammonium salt of chiral 1,1'-binaphthyl-2,2'-diamine and trifluoromethanesulfonimide (Tf(2)NH) shows excellent catalytic activity and enantioselectivity for the Diels-Alder reaction of alpha-acyloxyacroleins with cyclic dienes. For example, in the presence of 5 mol % of the ammonium catalyst, the Diels-Alder reaction of alpha-(cyclohexanecarbonyloxy)acrolein with cyclopentadiene proceeded in EtCN at -75 degrees C to give the adducts in 88% yield with 92% exo and 91% ee. This catalyst can be easily prepared in situ by mixing the commercially available chiral diamine and Tf(2)NH.
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Affiliation(s)
- Akira Sakakura
- Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Japan
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1478
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Sibi MP, Hasegawa M. Organocatalysis in radical chemistry. Enantioselective alpha-oxyamination of aldehydes. J Am Chem Soc 2007; 129:4124-5. [PMID: 17362013 PMCID: PMC2632679 DOI: 10.1021/ja069245n] [Citation(s) in RCA: 252] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mukund P Sibi
- Department of Chemistry, North Dakota State University, Fargo, North Dakota 58105, USA.
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1479
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Guo QX, Liu H, Guo C, Luo SW, Gu Y, Gong LZ. Chiral Brønsted Acid-Catalyzed Direct Asymmetric Mannich Reaction. J Am Chem Soc 2007; 129:3790-1. [PMID: 17358062 DOI: 10.1021/ja068236b] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Qi-Xiang Guo
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, 230026 China
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1480
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Rueping M, Ieawsuwan W, Antonchick AP, Nachtsheim BJ. Chiral Brønsted Acids in the Catalytic Asymmetric Nazarov Cyclization—The First Enantioselective Organocatalytic Electrocyclic Reaction. Angew Chem Int Ed Engl 2007; 46:2097-100. [PMID: 17278163 DOI: 10.1002/anie.200604809] [Citation(s) in RCA: 269] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Magnus Rueping
- Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt am Main, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany.
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1481
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Rueping M, Ieawsuwan W, Antonchick A, Nachtsheim B. Chirale Brønsted-Säuren in der katalytischen asymmetrischen Nazarov-Reaktion – die erste enantioselektive organokatalytische elektrocyclische Reaktion. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200604809] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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1482
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Rueping M, Sugiono E, Moreth S. Metal-Free, Enantioselective Strecker Reactions Catalyzed by Chiral BINOL and TADDOL Catalysts. Adv Synth Catal 2007. [DOI: 10.1002/adsc.200600405] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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1483
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Gu CL, Liu L, Sui Y, Zhao JL, Wang D, Chen YJ. Highly enantioselective Michael additions of α-cyanoacetate with chalcones catalyzed by bifunctional cinchona-derived thiourea organocatalyst. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.tetasy.2007.02.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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1484
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Linton BR, Reutershan MH, Aderman CM, Richardson EA, Brownell KR, Ashley CW, Evans CA, Miller SJ. Asymmetric Michael addition of α-nitro-ketones using catalytic peptides. Tetrahedron Lett 2007. [DOI: 10.1016/j.tetlet.2007.01.073] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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1485
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1486
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Mikata Y, Fujimoto T, Sugai Y, Yano S. Control of Intramolecular Ether-Oxygen Coordination in the Crystal Structure of Copper(II) Complexes With Dipicolylamine-Based Ligands. Eur J Inorg Chem 2007. [DOI: 10.1002/ejic.200600801] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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1487
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1488
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Abstract
The current status of organic synthesis is hampered by costly protecting-group strategies and lengthy purification procedures after each synthetic step. To circumvent these problems, the synthetic potential of multicomponent domino reactions has been utilized for the efficient and stereoselective construction of complex molecules from simple precursors in a single process. In particular, domino reactions mediated by organocatalysts are in a way biomimetic, as this principle is used very efficiently in the biosynthesis of complex natural products starting from simple precursors. In this Minireview, we discuss the current development of this fast-growing field.
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Affiliation(s)
- Dieter Enders
- Institut für Organische Chemie, RWTH Aachen, Landoltweg 1, 52074 Aachen, Germany.
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1489
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Tan K, Jacobsen E. Indium-Mediated Asymmetric Allylation of Acylhydrazones Using a Chiral Urea Catalyst. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200603354] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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1490
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Becker C, Hoben C, Kunz H. Enantioselective Organocatalysis of Strecker and Mannich Reactions Based on Carbohydrates. Adv Synth Catal 2007. [DOI: 10.1002/adsc.200600370] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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1491
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1492
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Pliego JR, Piló-Veloso D. Chemoselective Nucleophilic Fluorination Induced by Selective Solvation of the SN2 Transition State. J Phys Chem B 2007; 111:1752-8. [PMID: 17266358 DOI: 10.1021/jp066580p] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reaction of the fluoride ion with secondary alkyl halides leads to 90% of elimination reaction and only 10% of nucleophilic substitution in dipolar aprotic solvents. Adding water to the organic phase, the SN2 yield increases in the cost of decreased reactivity. Using ab initio calculations, we have shown that it is possible to increase the reaction rate and the selectivity toward the SN2 process through supramolecular organocatalysis. The catalytic concept is based on selective solvation of the transition state through two hydrogen bonds provided by the 1,4-benzenedimethanol. The two hydrogen bonds between the catalyst and the SN2 transition state favor this pathway while just one strong hydrogen bond between the catalyst and the fluoride ion leads to a lower stabilization of the nucleophile, resulting in a higher reaction rate. Our calculations predict that the substitution product increases to 40% yield because of the selective catalysis provided by the 1,4-benzenedimethanol.
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Affiliation(s)
- Josefredo R Pliego
- Departamento de Química, Universidade Federal de Minas Gerais 31270-901, Belo Horizonte, MG, Brazil.
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1493
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Procuranti B, Connon SJ. A reductase-mimicking thiourea organocatalyst incorporating a covalently bound NADH analogue: efficient 1,2-diketone reduction with in situ prosthetic group generation and recycling. Chem Commun (Camb) 2007:1421-3. [PMID: 17389979 DOI: 10.1039/b618792g] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new class of bifunctional organocatalyst promotes the chemoselective reduction of diketone electrophiles at catalytic loadings in the presence of an inorganic co-reductant.
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Affiliation(s)
- Barbara Procuranti
- Centre for Synthesis and Chemical Biology, School of Chemistry, University of Dublin, Trinity College, Dublin 2, Ireland
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1494
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Marcelli T, van Maarseveen JH, Hiemstra H. Cupreines and cupreidines: an emerging class of bifunctional cinchona organocatalysts. Angew Chem Int Ed Engl 2007; 45:7496-504. [PMID: 17051626 DOI: 10.1002/anie.200602318] [Citation(s) in RCA: 308] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the steadily expanding field of organocatalysis, cinchona alkaloids play a prominent role. Until the late 1990s, bifunctional catalysts based on this scaffold relied exclusively on the C9-hydroxy group as the hydrogen-bond donor. Recently, new cinchona catalysts have been developed that feature a phenolic OH group in the C6' position-a structural feature that allows a diverse set of reactions to be catalyzed in a highly stereoselective fashion. This Minireview describes the scope and modes of action of this new class of asymmetric bifunctional organocatalysts.
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Affiliation(s)
- Tommaso Marcelli
- Van't Hoff Institute for Molecular Sciences (HIMS), Universiteit van Amsterdam, Nieuwe Achtergracht 129, 1018WS Amsterdam, The Netherlands
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1495
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Niehaus TA. Mechanism of hydrogen bond assisted cis-trans isomerization in the excited state of 2-naphthol. J Chem Phys 2007; 126:034303. [PMID: 17249867 DOI: 10.1063/1.2428289] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Stationary points on the ground and first two excited state potential energy surfaces of 2-naphthol and the hydrogen bonded complex 2-naphtholNH(3) have been located using an approximate method (time dependent density functional based tight-binding) based on time dependent density functional theory (TDDFT). For the obtained extrema, single point calculations at the full TDDFT level (PW916-311+G(**)) were performed for validation purposes. The energetical ordering of the cis and trans forms of 2-naphthol in the different electronic states is found to be in good agreement with available experimental data. Interestingly, also the optical spectrum is correctly predicted by TDDFT in contrast to calculations on unsubstituted acenes in the literature. Besides the stationary points, also the minimum energy paths connecting them are calculated using an adaptive nudged elastic band approach in order to estimate isomerization barriers. While the increase of barrier height going from the ground to the first excited state is already documented, the authors find as a new result a significant barrier reduction upon hydrogen bond formation in the S(2). The observed effect can contribute to the explanation of recent experiments on infrared laser induced cis-trans isomerization in 2-naphthol.
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Affiliation(s)
- Thomas A Niehaus
- Bremen Center for Computational Material Science, University of Bremen, D-28359 Bremen, Germany
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1496
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Movassaghi M, Chen B. Stereoselective Intermolecular Formal [3+3] Cycloaddition Reaction of Cyclic Enamines and Enones. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200603302] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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1497
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1498
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Affiliation(s)
- Subhas Chandra Pan
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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1499
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Zeng W, Chen GY, Zhou YG, Li YX. Hydrogen-Bonding Directed Reversal of Enantioselectivity. J Am Chem Soc 2007; 129:750-1. [PMID: 17243797 DOI: 10.1021/ja067346f] [Citation(s) in RCA: 215] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Wei Zeng
- Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Lu, Dalian 116023, China
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1500
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Tillman AL, Dixon DJ. An enantioselective Brønsted acid catalyzed enamine Mannich reaction. Org Biomol Chem 2007; 5:606-9. [PMID: 17285167 DOI: 10.1039/b616143j] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An enantioselective Brønsted acid catalyzed Mannich reaction between acetophenone derived enamines and N-Boc imines has been developed. Simple diol (S)-H(8)-BINOL has been identified as the optimal catalyst, to afford versatile beta-amino aryl ketones in good yield and enantiomeric excess.
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Affiliation(s)
- A Louise Tillman
- University Chemical Laboratory, University of Cambridge, Lensfield Road, Cambridge, UKCB2 1EW
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