851
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Ibrahem I, Casas J, Córdova A. Direct Catalytic Enantioselective α-Aminomethylation of Ketones. Angew Chem Int Ed Engl 2004; 43:6528-31. [PMID: 15578760 DOI: 10.1002/anie.200460678] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ismail Ibrahem
- Department of Organic Chemistry, The Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden
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852
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Ibrahem I, Casas J, Córdova A. Direct Catalytic Enantioselective α-Aminomethylation of Ketones. Angew Chem Int Ed Engl 2004. [DOI: 10.1002/ange.200460678] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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853
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Sundén H, Engqvist M, Casas J, Ibrahem I, Córdova A. Direct Amino Acid Catalyzed Asymmetric α Oxidation of Ketones with Molecular Oxygen. Angew Chem Int Ed Engl 2004. [DOI: 10.1002/ange.200460295] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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854
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Abate A, Brenna E, Fuganti C, Gatti FG, Serra S. Lipase-catalysed preparation of enantiomerically enriched odorants. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.molcatb.2004.09.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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855
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Mediavilla Urbaneja L, Krause N. Synthesis of Novel Bifunctional Michael Acceptors. European J Org Chem 2004. [DOI: 10.1002/ejoc.200400419] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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856
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Proline-catalyzed asymmetric aldol reactions of tetrahydro-4H-thiopyran-4-one with aldehydes. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.09.061] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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857
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Wu YS, Cai J, Hu ZY, Lin GX. A new class of metal-free catalysts for direct diastereo- and regioselective Mannich reactions in aqueous media. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.09.174] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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858
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Branchadell V, Crévisy C, Grée R. From Allylic Alcohols to Aldols by Using Iron Carbonyls as Catalysts: Computational Study on a Novel Tandem Isomerization-Aldolization Reaction. Chemistry 2004; 10:5795-803. [PMID: 15472940 DOI: 10.1002/chem.200400466] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The tandem isomerization-aldolization reaction between allyl alcohol and formaldehyde mediated by [Fe(CO)3] was studied with the density functional B3LYP method. Starting from the key [(enol)Fe(CO)3] complex, several reaction paths for the reaction with formaldehyde were explored. The results show that the most favorable reaction path involves first an enol/allyl alcohol ligand-exchange process followed by direct condensation of formaldehyde with the free enol. During this process, formation of the new C-C bond takes place simultaneously with a proton transfer between the enol and the aldehyde. Therefore, the role of [Fe(CO)3] is to catalyze the allyl alcohol to enol isomerization affording the free enol, which adds to the aldehyde in a carbonyl-ene type reaction. Similar results were obtained for the reaction between allyl alcohol and acetaldehyde.
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Affiliation(s)
- Vicenç Branchadell
- Departament de Química, Universitat Autònoma de Barcelona, Edifici Cn, 08193 Bellaterra, Spain.
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859
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Hayashi Y, Yamaguchi J, Hibino K, Sumiya T, Urushima T, Shoji M, Hashizume D, Koshino H. A Highly Active 4-Siloxyproline Catalyst for Asymmetric Synthesis. Adv Synth Catal 2004. [DOI: 10.1002/adsc.200404166] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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860
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Benzoimidazole–pyrrolidine (BIP), a highly reactive chiral organocatalyst for aldol process. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.08.171] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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861
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Edin M, Bäckvall JE, Córdova A. Tandem enantioselective organo- and biocatalysis: a direct entry for the synthesis of enantiomerically pure aldols. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.08.079] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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862
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Affiliation(s)
- Erik J Sorensen
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
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863
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Abstract
Studies of carbohydrates have been hampered by the lack of chemical strategies for the expeditious construction and coupling of differentially protected monosaccharides. Here, a synthetic route based on aldol coupling of three aldehydes is presented for the de novo production of polyol differentiated hexoses in only two chemical steps. The dimerization of alpha-oxyaldehydes, catalyzed by l-proline, is then followed by a tandem Mukaiyama aldol addition-cyclization step catalyzed by a Lewis acid. Differentially protected glucose, allose, and mannose stereoisomers can each be selected, in high yield and stereochemical purity, simply by changing the solvent and Lewis acid used. The reaction sequence also efficiently produces (13)C-labeled analogs, as well as structural variants such as 2-amino- and 2-thio-substituted derivatives.
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Affiliation(s)
- Alan B Northrup
- Department of Chemistry, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
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864
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Córdova A, Sundén H, Engqvist M, Ibrahem I, Casas J. The direct amino acid-catalyzed asymmetric incorporation of molecular oxygen to organic compounds. J Am Chem Soc 2004; 126:8914-5. [PMID: 15264820 DOI: 10.1021/ja047930t] [Citation(s) in RCA: 192] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have disclosed the direct catalytic incorporation of 1O2 to aldehydes. The unprecedented amino acid-catalyzed asymmetric alpha-oxidation of aldehydes with molecular oxygen or air proceeded with high chemoselectivity and was a direct entry for the synthesis of both enantiomers of terminal diols. The results demonstrated that simple amino acids accomplished catalytic asymmetric oxidations with molecular oxygen or air, which has previously been considered to be in the domain of enzymes and chiral transition-metal complexes. The efficiency of the catalytic process may warrant the existence of an ancient pathway for the synthesis of hydroxylated organic compounds.
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Affiliation(s)
- Armando Córdova
- Department of Organic Chemistry, The Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
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865
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Wang W, Wang J, Li H, Liao L. An amine sulfonamide organocatalyst for promoting direct, highly enantioselective α-aminoxylation reactions of aldehydes and ketones. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.08.029] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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866
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Wang W, Wang J, Li H. Catalysis of highly stereoselective Mannich-type reactions of ketones with α-imino esters by a pyrrolidine-sulfonamide. Synthesis of unnatural α-amino acids. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.08.032] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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867
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Posner PG, Motherwell PW. Tetrahedron reports on organic chemistry. Tetrahedron 2004. [DOI: 10.1016/s0040-4020(04)01396-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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868
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Abstract
[reaction: see text] The total synthesis of (+)-cocaine is described. An extension of the recently reported proline catalyzed intramolecular enol-exo-aldol reaction to a meso-dialdehyde provided the tropane ring skeleton directly with good enantiomeric excess. The meso-dialdehyde was prepared using a 2-azaallyllithium [3 + 2] cycloaddition to generate a cis-2,5-disubstituted pyrrolidine. Overall, the synthesis proceeded in 6.5% yield and 86% ee over 14 linear steps starting from commercially available 3-benzyloxy-1-propanol.
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Affiliation(s)
- Douglas M Mans
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
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869
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Kan JTW, Toy P. Poly(ethylene glycol)-supported α,α,α-trifluoroacetophenone in dioxirane mediated alkene epoxidation reactions. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.06.085] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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870
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Saito S, Yamamoto H. Design of acid-base catalysis for the asymmetric direct Aldol reaction. Acc Chem Res 2004; 37:570-9. [PMID: 15311956 DOI: 10.1021/ar030064p] [Citation(s) in RCA: 353] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Proper design of acid-base catalysis has been shown to be effective for achieving high reactivity and selectivity in the asymmetric direct aldol reaction during the development of diamine-Brønsted acid types of catalyst. In this study, two principal approaches have been implemented to create a new type of catalysis and high catalytic efficiency: one is the creation of a highly viable acidic function within acid-base catalysts; the other is the creation of rather complicated but more cooperatively arranged hydrogen-bond networks that would be expected to stabilize a transition state, thereby promoting new reactivity and selectivity.
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Affiliation(s)
- Susumu Saito
- Institute for Advanced Research & Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602, Japan
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871
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Ian Storer R, MacMillan DW. Enantioselective organocatalytic aldehyde–aldehyde cross-aldol couplings. The broad utility of α-thioacetal aldehydes. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.04.089] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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872
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Abstract
The discovery of short peptide sequences that function as asymmetric catalysts for a variety of reactions is documented. The evolution of the project from an exercise in rational design to an endeavor that combines combinatorial screening with various mechanism-based experiments is presented. The specific development of catalysts for enantioselective acylation, phosphorylation, conjugate addition, and Morita-Baylis-Hillman reactions is described.
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Affiliation(s)
- Scott J Miller
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA.
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873
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Casas J, Sundén H, Córdova A. Direct organocatalytic asymmetric α-hydroxymethylation of ketones and aldehydes. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.06.062] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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874
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Ohshima T, Shibuguchi T, Fukuta Y, Shibasaki M. Catalytic asymmetric phase-transfer reactions using tartrate-derived asymmetric two-center organocatalysts. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.05.120] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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875
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Ooi T, Kameda M, Taniguchi M, Maruoka K. Development of Highly Diastereo- and Enantioselective Direct Asymmetric Aldol Reaction of a Glycinate Schiff Base with Aldehydes Catalyzed by Chiral Quaternary Ammonium Salts. J Am Chem Soc 2004; 126:9685-94. [PMID: 15291572 DOI: 10.1021/ja048865q] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A highly efficient direct asymmetric aldol reaction of a glycinate Schiff base with aldehydes has been achieved under mild organic/aqueous biphasic conditions with excellent stereochemical control, using chiral quaternary ammonium salt 1b as a phase-transfer catalyst. The initially developed reaction conditions, using 2 equiv of aqueous base (1% NaOH (aq)), exhibited inexplicably limited general applicability in terms of aldehyde acceptors. The mechanistic investigation revealed the intervention of an unfavorable yet inevitable retro aldol process involving the chiral catalyst. On the basis of this information, a reliable procedure has been established by use of a catalytic amount of 1% NaOH (aq) and ammonium chloride, which tolerates a wide range of aldehydes to afford the corresponding anti-beta-hydroxy-alpha-amino esters almost exclusively in an essentially optically pure form.
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Affiliation(s)
- Takashi Ooi
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
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876
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Wang W, Wang J, Li H. A Simple and Efficient l-Prolinamide-Catalyzed α-Selenenylation Reaction of Aldehydes. Org Lett 2004; 6:2817-20. [PMID: 15281777 DOI: 10.1021/ol0488946] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An efficient and simple l-prolinamide-catalyzed alpha-selenenylation reaction of aldehydes with N-(phenylseleno)phthalimide has been developed for the efficient preparation of alpha-phenylselenoaldehydes. Such compounds are versatile building blocks for the synthesis of alpha,beta-unsaturated aldehydes, allylic alcohols, and amines. [reaction: see text]
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Affiliation(s)
- Wei Wang
- Department of Chemistry, University of New Mexico, Albuquerque, NM 87131-0001, USA.
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877
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Geller T, Gerlach A, Krüger CM, Militzer HC. Novel conditions for the Juliá–Colonna epoxidation reaction providing efficient access to chiral, nonracemic epoxides. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.04.188] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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878
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879
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Hartikka A, Arvidsson PI. Rational design of asymmetric organocatalysts––increased reactivity and solvent scope with a tetrazolic acid. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.tetasy.2004.04.029] [Citation(s) in RCA: 183] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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880
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Chan V, Kim JG, Jimeno C, Carroll PJ, Walsh PJ. Dynamic Kinetic Resolution of Atropisomeric Amides. Org Lett 2004; 6:2051-3. [PMID: 15176816 DOI: 10.1021/ol0492952] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Using L-proline as catalyst in the asymmetric aldol reaction and a series of benzamides and naphthamides, we have accomplished a dynamic kinetic resolution that simultaneously establishes the stereochemistry of the atropisomeric amide's chiral axis and a stereogenic center. The enantioselectivities ranged from 82% to 95% and the diastereoselectivities from 2.1:1 to 7.0:1.
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Affiliation(s)
- Vincent Chan
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, USA
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881
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Fierman MB, O'Leary DJ, Steinmetz WE, Miller SJ. Structure-Selectivity Relationships and Structure for a Peptide-Based Enantioselective Acylation Catalyst. J Am Chem Soc 2004; 126:6967-71. [PMID: 15174866 DOI: 10.1021/ja049661c] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Studies of analogues of a recently discovered enantioselective peptide-based catalyst for enantioselective acylation reactions have led to mechanistic insight and improved catalysts. Systematic replacement of each residue within the parent peptide with alanine of the appropriate stereochemistry allows for an unambiguous evaluation of the kinetic role of each amino acid side chain in the catalyst. The results of the alanine scan support a bifunctional catalysis mechanism at the heart of the origin of enantioselectivity. In addition, an experimentally derived solution structure of the peptide-based catalyst is presented that supports a key role for each residue within the peptide chain.
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Affiliation(s)
- Matthew B Fierman
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467-3860, USA
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882
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Hayashi Y, Tsuboi W, Shoji M, Suzuki N. Application of high pressure, induced by water freezing, to the direct asymmetric aldol reaction. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.03.190] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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883
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884
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885
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Chandrasekhar S, Narsihmulu C, Reddy N, Sultana S. Asymmetric aldol reactions in poly(ethylene glycol) catalyzed by l-proline. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.03.116] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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886
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Reetz MT. Controlling the enantioselectivity of enzymes by directed evolution: practical and theoretical ramifications. Proc Natl Acad Sci U S A 2004; 101:5716-22. [PMID: 15079053 PMCID: PMC395973 DOI: 10.1073/pnas.0306866101] [Citation(s) in RCA: 240] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2003] [Indexed: 11/18/2022] Open
Abstract
A fundamentally new approach to asymmetric catalysis in organic chemistry is described based on the in vitro evolution of enantioselective enzymes. It comprises the appropriate combination of gene mutagenesis and expression coupled with an efficient high-throughput screening system for evaluating enantioselectivity (enantiomeric excess assay). Several such cycles lead to a "Darwinistic" process, which is independent of any knowledge concerning the structure or the mechanism of the enzyme being evolved. The challenge is to choose the optimal mutagenesis methods to navigate efficiently in protein sequence space. As a first example, the combination of error-prone mutagenesis, saturation mutagenesis, and DNA-shuffling led to a dramatic enhancement of enantioselectivity of a lipase acting as a catalyst in the kinetic resolution of a chiral ester. Mutations at positions remote from the catalytically active center were identified, a surprising finding, which was explained on the basis of a novel relay mechanism. The scope and limitations of the method are discussed, including the prospect of directed evolution of stereoselective hybrid catalysts composed of robust protein hosts in which transition metal centers have been implanted.
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Affiliation(s)
- Manfred T Reetz
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim/Ruhr, Germany.
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887
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Momiyama N, Torii H, Saito S, Yamamoto H. O-nitroso aldol synthesis: Catalytic enantioselective route to alpha-aminooxy carbonyl compounds via enamine intermediate. Proc Natl Acad Sci U S A 2004; 101:5374-8. [PMID: 15067138 PMCID: PMC397388 DOI: 10.1073/pnas.0307785101] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Indexed: 11/18/2022] Open
Abstract
The approach using pyrrolidine enamine as substrate has been studied for this synthesis, and an important catalyst structural feature has been developed. After survey of pyrrolidine-based Brønsted acid catalyst, tetrazole catalyst (3f) was found to be optimal in synthesis of aminooxy carbonyl compounds in high yields, with complete enantioselectivity not only for aldehydes but also for ketones.
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Affiliation(s)
- Norie Momiyama
- Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, Chicago, IL 60637, USA
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888
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Abstract
Chirality of organic molecules plays an enormous role in areas ranging from medicine to material science, yet the synthesis of such entities in one enantiomeric form is one of the most difficult challenges. The advances being made stem from the convergence of a broader understanding of theory and how structure begets function, the developments in the interface between organic and inorganic chemistry and, most notably, the organic chemistry of the transition metals, and the continuing advancements in the tools to help define structure, especially in solution. General themes for designing catalysts to effect asymmetric induction are helping to make this strategy more useful, in general, with the resultant effect of a marked enhancement of synthetic efficiency.
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Affiliation(s)
- Barry M Trost
- Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA.
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889
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Denmark SE, Bui T. Chiral phosphoramide-catalyzed, enantioselective, directed cross-aldol reactions of aldehydes. Proc Natl Acad Sci U S A 2004; 101:5439-44. [PMID: 15067133 PMCID: PMC397401 DOI: 10.1073/pnas.0307212101] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2003] [Indexed: 11/18/2022] Open
Abstract
Catalytic, enantioselective, directed cross-aldol reactions of aldehydes are described. The addition of isobutyraldehyde trichlorosilyl enolate 2 to various aldehydes in the presence of 10 mol % bisphosphoramide 4 provides aldol products in high yields with moderate to good enantioselectivities. The reaction works well with a wide range of aromatic, olefinic, and aliphatic aldehydes. Enantioselectivities are highly dependent on the electronic nature of the aldehyde substituent. Hammett studies reveal that enantioselectivity increases as aldehydes become either more electron rich or more electron poor.
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Affiliation(s)
- Scott E Denmark
- Department of Chemistry, Roger Adams Laboratory, University of Illinois, Urbana, IL 61801, USA.
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890
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Kobayashi S, Ueno M, Saito S, Mizuki Y, Ishitani H, Yamashita Y. Air-stable, storable, and highly efficient chiral zirconium catalysts for enantioselective Mannich-type, aza Diels-Alder, aldol, and hetero Diels-Alder reactions. Proc Natl Acad Sci U S A 2004; 101:5476-81. [PMID: 15067139 PMCID: PMC397408 DOI: 10.1073/pnas.0307870101] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2003] [Indexed: 11/18/2022] Open
Abstract
For the synthesis of optically active compounds, chiral catalysts have attracted much attention because large quantities of optically active molecules can be prepared from a small amount of a chiral source. However, many chiral catalysts are often unstable in air (oxygen) and/or in the presence of water. This is especially the case in chiral Lewis acid catalysis, because most Lewis acids are air- and moisture-sensitive. Therefore, many catalysts are prepared in situ in an appropriate solvent just before use, and they cannot be stored for extended periods. We have developed air-stable, storable, and highly efficient chiral zirconium Lewis acids. The catalysts promoted asymmetric Mannich-type, aza Diels-Alder, aldol, and hetero Diels-Alder reactions efficiently with high enantioselectivities. A key to stabilizing the catalysts is an appropriate combination of chiral zirconium Lewis acids with molecular sieves, and the zirconium-molecular sieves-combined catalysts can be stored for extended periods in air at room temperature without loss of activity. Moreover, it has been demonstrated that the catalysts can be recovered and reused.
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Affiliation(s)
- Shu Kobayashi
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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891
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Tang Z, Jiang F, Cui X, Gong LZ, Mi AQ, Jiang YZ, Wu YD. Enantioselective direct aldol reactions catalyzed by L-prolinamide derivatives. Proc Natl Acad Sci U S A 2004; 101:5755-60. [PMID: 15079057 PMCID: PMC395980 DOI: 10.1073/pnas.0307176101] [Citation(s) in RCA: 250] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
l-Prolinamides 2, prepared from l-proline and simple aliphatic and aromatic amines, have been found to be active catalysts for the direct aldol reaction of 4-nitrobenzaldehyde with neat acetone at room temperature. They give moderate enantioselectivities of up to 46% enantiomeric excess (ee). The enantioselectivity increases as the amide N-H becomes a better hydrogen bond donor. l-Prolinamides 3, derived from the reaction of l-proline with alpha,beta-hydroxyamines such that there is a terminal hydroxyl group, show more efficient catalysis and higher enantioselectivities. In particular, catalyst 3h, prepared from l-proline and (1S,2S)-diphenyl-2-aminoethanol, exhibits high enantioselectivities of up to 93% ee for aromatic aldehydes and up to >99% ee for aliphatic aldehydes under -25 degrees C. Model reactions of benzaldehyde with three enamines derived from the condensation of prolinamides with acetone have been studied by quantum mechanics calculations. The calculations reveal that the amide N-H and the terminal hydroxyl groups form hydrogen bonds with the benzaldehyde substrate. These hydrogen bonds reduce the activation energy and cause high enantioselectivity. Our results suggest a new strategy in the design of new organic catalysts for direct asymmetric aldol reactions and related transformations.
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Affiliation(s)
- Zhuo Tang
- Key Laboratory for Asymmetric Synthesis and Chirotechnology of Sichuan Province, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China
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892
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Halland N, Braunton A, Bachmann S, Marigo M, Jørgensen KA. Direct Organocatalytic Asymmetric α-Chlorination of Aldehydes. J Am Chem Soc 2004; 126:4790-1. [PMID: 15080678 DOI: 10.1021/ja049231m] [Citation(s) in RCA: 272] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The direct organocatalytic enantioselective alpha-chlorination of aldehydes has been developed. The reaction proceeds for a series of different aldehydes with NCS as the chlorine source using easily available catalysts such as l-proline amide and (2R,5R)-diphenylpyrrolidine. The alpha-chloro aldehydes are obtained in up to 99% yield and up to 95% ee. The synthetic utility of the enantioselective alpha-chlorination of aldehydes is demonstrated by transformation of the alpha-chloro aldehydes to the corresponding alpha-chloro alcohols (>90% yield) by standard reduction and further transformation to both a terminal epoxide and amino alcohol, both obtained without loss of optical purity. Oxidation of the alpha-chloro aldehydes followed by esterification gave optically active alpha-chloro esters without loss of optical purity. It is demonstrated that these optically active alpha-chloro esters can be converted into nonproteinogenic amino acids in overall high yields, maintaining the enantiomeric excess obtained in the catalytic enantioselective alpha-chlorination step.
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Affiliation(s)
- Nis Halland
- Danish National Research Foundation, Center for Catalysis, Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark
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893
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Tetrahedron reports on organic chemistry. Tetrahedron 2004. [DOI: 10.1016/s0040-4020(04)00315-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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894
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Boc-l-proline as a new chiral ligand for enantioselective phenylacetylene addition to aromatic aldehydes. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.tetasy.2004.01.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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895
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Abstract
The direct catalytic asymmetric addition of unmodified carbonyl compounds to preformed or in situ-generated imines has emerged as a promising new route to optically enriched alpha- and beta-amino acid derivatives, beta-lactams, and 1,2- and gamma-amino alcohols. The direct catalytic asymmetric Mannich reactions are mediated by small organometallic and organic amine catalysts that can achieve levels of selectivity similar to those possible with natural enzymes. The different small-molecule catalysts described here are complementary in their applications. They also complement each other in syn or anti selectivity of the direct asymmetric Mannich reaction. In this Account, we highlight the recent developments in and contributions to this research.
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Affiliation(s)
- Armando Córdova
- Arrhenius Laboratory, Department of Organic Chemistry, Stockholm University, SE-10691 Stockholm, Sweden
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896
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Cochard F, Laronze M, Sigaut P, Sapi J, Laronze JY. Synthesis of carbazoles by a balanced four component condensation. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2003.12.099] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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897
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Ohshima T. Enantioselective Total Syntheses of Several Bioactive Natural Products Based on the Development of Practical Asymmetric Catalysis. Chem Pharm Bull (Tokyo) 2004; 52:1031-52. [PMID: 15340187 DOI: 10.1248/cpb.52.1031] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
I present herewith enantioselective total syntheses of several bioactive natural products, such as (-)-strychnine, (+)-decursin, (-)-cryptocaryolone diacetate, (-)-fluoxetine, and aeruginosin 298-A, based on practical asymmetric catalyses (Michael reaction, epoxidation, and phase-transfer reaction) that I developed with co-workers in Prof. Shibasaki's group over the past 5 years. In the first part of this review, I discuss the great improvement of catalyst efficiency in an ALB-catalyzed asymmetric Michael reaction of malonate and application to the pre-manufacturing scale (greater than kilogram scale) and enantioselective total synthesis of (-)-strychnine with the development of novel domino cyclization. To broaden the substrate generality of the Michael reaction, we developed a highly stable, storable, and reusable La-O-linked-BINOL complex. Further extension of the reaction using beta-keto ester as a Michael donor was achieved with the development of a La-NR-linked-BINOL complex, thereby improving indole alkaloid syntheses. In the second section, I discuss enantioselective total synthesis of (+)-decursin using catalytic asymmetric epoxidation. To achieve the synthesis, we developed a new La-BINOL-Ph(3)As = O (1:1:1) complex catalyst system, which has much higher reactivity and broader substrate generality than the previously developed catalyst systems. This allowed us to achieve catalytic asymmetric epoxidation of alpha,beta-unsaturated carboxylic acid derivatives with high enantioselectivity and broad substrate generality for the first time by changing the lanthanide metal and reaction conditions. Among them, catalytic asymmetric epoxidation of alpha,beta-unsaturated morpholinyl amides is quite useful in terms of synthetic utility of the corresponding alpha,beta-epoxy morpholinyl amides. Highly catalyst-controlled enantio- or diastereoselective epoxidation of the alpha,beta-unsaturated morpholinyl amides, coupled with diastereoselective reduction of beta-hydroxy ketones, enabled the synthesis of all possible stereoisomers of 1,3-polyol arrays with successful enantioselective total synthesis of several 1,3-polyol natural products, such as (-)-cryptocaryolone diacetate. In addition, the development of a new regioselective epoxide-opening reaction of alpha,beta-epoxy amides to the corresponding alpha- and beta-hydroxy amides enhanced the usefulness of the present epoxidation and was applied to the enantioselective total synthesis of (-)-fluoxetine. In the final section, I report the development of a new asymmetric two-center organocatalyst (TaDiAS) and its application to the enantioselective synthesis of aeruginosin 298-A and its analogues. Because of the remarkable structural diversity of TaDiAS, a practical asymmetric phase-transfer reaction with broad substrate generality was achieved. As a result, we succeeded in developing a highly versatile synthetic method for aeruginosin 298-A and its analogues. Inhibitory activity studies of the compounds against the serine protease trypsin provided preliminary information about their structure-activity relations.
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Affiliation(s)
- Takashi Ohshima
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan. .-tokyo.ac.jp
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898
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Mhadgut SC, Bucsi I, Török M, Török B. Sonochemical asymmetric hydrogenation of isophorone on proline modified Pd/Al2O3catalysts. Chem Commun (Camb) 2004:984-5. [PMID: 15069506 DOI: 10.1039/b315244h] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The sonochemical asymmetric hydrogenation of isophorone (3,3,5-trimethyl-2-cyclohexenone) by proline-modified Pd/Al2O3 catalysts is described; presonication of a commercial Pd/Al2O3-proline catalytic system resulted in highly enhanced enantioselectivities (up to 85% ee).
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Affiliation(s)
- Shilpa C Mhadgut
- Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
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899
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Maggiotti V, Bahmanyar S, Reiter M, Resmini M, Houk K, Gouverneur V. Unusual reversal of regioselectivity in antibody-mediated aldol additions with unsymmetrical methyl ketones. Tetrahedron 2004. [DOI: 10.1016/j.tet.2003.10.115] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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900
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Posner PG, Motherwell PW. Tetrahedron reports on organic chemistry. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(03)01884-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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