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Abstract
Nitroxides, also known as nitroxyl radicals, are long-lived or stable radicals with the general structure R1R2N-O•. The spin distribution over the nitroxide N and O atoms contributes to the thermodynamic stability of these radicals. The presence of bulky N-substituents R1 and R2 prevents nitroxide radical dimerization, ensuring their kinetic stability. Despite their reactivity toward various transient C radicals, some nitroxides can be easily stored under air at room temperature. Furthermore, nitroxides can be oxidized to oxoammonium salts (R1R2N═O+) or reduced to anions (R1R2N-O-), enabling them to act as valuable oxidants or reductants depending on their oxidation state. Therefore, they exhibit interesting reactivity across all three oxidation states. Due to these fascinating properties, nitroxides find extensive applications in diverse fields such as biochemistry, medicinal chemistry, materials science, and organic synthesis. This review focuses on the versatile applications of nitroxides in organic synthesis. For their use in other important fields, we will refer to several review articles. The introductory part provides a brief overview of the history of nitroxide chemistry. Subsequently, the key methods for preparing nitroxides are discussed, followed by an examination of their structural diversity and physical properties. The main portion of this review is dedicated to oxidation reactions, wherein parent nitroxides or their corresponding oxoammonium salts serve as active species. It will be demonstrated that various functional groups (such as alcohols, amines, enolates, and alkanes among others) can be efficiently oxidized. These oxidations can be carried out using nitroxides as catalysts in combination with various stoichiometric terminal oxidants. By reducing nitroxides to their corresponding anions, they become effective reducing reagents with intriguing applications in organic synthesis. Nitroxides possess the ability to selectively react with transient radicals, making them useful for terminating radical cascade reactions by forming alkoxyamines. Depending on their structure, alkoxyamines exhibit weak C-O bonds, allowing for the thermal generation of C radicals through reversible C-O bond cleavage. Such thermally generated C radicals can participate in various radical transformations, as discussed toward the end of this review. Furthermore, the application of this strategy in natural product synthesis will be presented.
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Affiliation(s)
- Dirk Leifert
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
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Qian B, Zhang L, Zhang G, Fu Y, Zhu X, Shen G. Thermodynamic Evaluation on Alkoxyamines of TEMPO Derivatives, Stable Alkoxyamines or Potential Radical Donors? ChemistrySelect 2022. [DOI: 10.1002/slct.202204144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Bao‐Chen Qian
- School of Medical Engineering Jining Medical University Jining Shandong 272000 P. R. China
| | - Lu Zhang
- School of Medical Engineering Jining Medical University Jining Shandong 272000 P. R. China
| | - Gao‐Shuai Zhang
- School of Medical Engineering Jining Medical University Jining Shandong 272000 P. R. China
| | - Yan‐Hua Fu
- College of Chemistry and Environmental Engineering Anyang Institute of Technology Anyang Henan 455000 P. R. China
| | - Xiao‐Qing Zhu
- The State Key Laboratory of Elemento-Organic Chemistry Department of Chemistry Nankai University Tianjin 300071 P. R. China
| | - Guang‐Bin Shen
- School of Medical Engineering Jining Medical University Jining Shandong 272000 P. R. China
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Cha H, Chai JY, Kim HB, Chi DY. Synthesis of aliphatic α-ketoamides from α-substituted methyl ketones via a Cu-catalyzed aerobic oxidative amidation. Org Biomol Chem 2021; 19:4320-4326. [PMID: 33904536 DOI: 10.1039/d1ob00129a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
α-Ketoamides are an important key functional group and have been used as versatile and valuable intermediates and synthons in a variety of functional group transformations. Synthetic methods for making aryl α-ketoamides as drug candidates have been greatly improved through metal-catalyzed aerobic oxidative amidations. However, the preparation of alkyl α-ketoamides through metal-catalyzed aerobic oxidative amidations has not been reported because generating α-ketoamides from aliphatic ketones with two α-carbons theoretically provides two distinct α-ketoamides. Our strategy is to activate the α-carbon by introducing an N-substituent at one of the two α-positions. The key to this strategy is how heterocyclic compounds such as triazoles and imidazoles affect the selectivity of the synthesis of the alkyl α-ketoamides. From this basic concept, and by optimizing the reaction and elucidating the mechanism of the synthesis of aryl α-ketoamides via a copper-catalyzed aerobic oxidative amidation, we prepared fourteen aliphatic α-ketoamides in high yields (48-84%).
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Affiliation(s)
- Hyojin Cha
- Department of Chemistry, Sogang University, 35 Baekbeomro Mapogu, Seoul 04107, Korea.
| | - Jin Young Chai
- Department of Chemistry, Sogang University, 35 Baekbeomro Mapogu, Seoul 04107, Korea.
| | - Hyeong Baik Kim
- Department of Chemistry, Sogang University, 35 Baekbeomro Mapogu, Seoul 04107, Korea.
| | - Dae Yoon Chi
- Department of Chemistry, Sogang University, 35 Baekbeomro Mapogu, Seoul 04107, Korea.
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Metrano AJ, Chinn AJ, Shugrue CR, Stone EA, Kim B, Miller SJ. Asymmetric Catalysis Mediated by Synthetic Peptides, Version 2.0: Expansion of Scope and Mechanisms. Chem Rev 2020; 120:11479-11615. [PMID: 32969640 PMCID: PMC8006536 DOI: 10.1021/acs.chemrev.0c00523] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Low molecular weight synthetic peptides have been demonstrated to be effective catalysts for an increasingly wide array of asymmetric transformations. In many cases, these peptide-based catalysts have enabled novel multifunctional substrate activation modes and unprecedented selectivity manifolds. These features, along with their ease of preparation, modular and tunable structures, and often biomimetic attributes make peptides well-suited as chiral catalysts and of broad interest. Many examples of peptide-catalyzed asymmetric reactions have appeared in the literature since the last survey of this broad field in Chemical Reviews (Chem. Rev. 2007, 107, 5759-5812). The overarching goal of this new Review is to provide a comprehensive account of the numerous advances in the field. As a corollary to this goal, we survey the many different types of catalytic reactions, ranging from acylation to C-C bond formation, in which peptides have been successfully employed. In so doing, we devote significant discussion to the structural and mechanistic aspects of these reactions that are perhaps specific to peptide-based catalysts and their interactions with substrates and/or reagents.
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Affiliation(s)
- Anthony J. Metrano
- AstraZeneca Oncology R&D, 35 Gatehouse Dr., Waltham, MA 02451, United States
| | - Alex J. Chinn
- Department of Chemistry, Princeton University, Princeton, NJ 08544, United States
| | - Christopher R. Shugrue
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Elizabeth A. Stone
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520, United States
| | - Byoungmoo Kim
- Department of Chemistry, Clemson University, Clemson, SC 29634, United States
| | - Scott J. Miller
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520, United States
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Akagawa K, Kudo K. Design of Peptide Catalysts by Combining Secondary Structural Units for Selective Reactions. J SYN ORG CHEM JPN 2019. [DOI: 10.5059/yukigoseikyokaishi.77.1222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Kazuaki Kudo
- Institute of Industrial Science, The University of Tokyo
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Tang L, Yang Z, Yang F, Huang Y, Chen H, Cheng H, Song W, Ren B, Zhou Q. Catalyst‐Free α‐Aminoxylation of 1,3‐Dicarbonyl Compounds with TEMPO Using Selectfluor as an Oxidant. ChemistrySelect 2019. [DOI: 10.1002/slct.201903856] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Lin Tang
- College of Chemistry and Chemical EngineeringXinyang Normal University Xinyang 464000 P. R. China
| | - Zhen Yang
- College of Chemistry and Chemical EngineeringXinyang Normal University Xinyang 464000 P. R. China
| | - Fang Yang
- College of Chemistry and Chemical EngineeringXinyang Normal University Xinyang 464000 P. R. China
| | - Yifan Huang
- College of Chemistry and Chemical EngineeringXinyang Normal University Xinyang 464000 P. R. China
| | - Hanfei Chen
- College of Chemistry and Chemical EngineeringXinyang Normal University Xinyang 464000 P. R. China
| | - Hao Cheng
- College of Chemistry and Chemical EngineeringXinyang Normal University Xinyang 464000 P. R. China
| | - Weiyan Song
- College of Chemistry and Chemical EngineeringXinyang Normal University Xinyang 464000 P. R. China
| | - Bo Ren
- College of Chemistry and Chemical EngineeringXinyang Normal University Xinyang 464000 P. R. China
| | - Qiuju Zhou
- College of Chemistry and Chemical EngineeringXinyang Normal University Xinyang 464000 P. R. China
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Ohshima T, Yazaki R, Taninokuchi S. Mechanistic Insight into Catalytic Aerobic Chemoselective α-Oxidation of Acylpyrazoles. HETEROCYCLES 2019. [DOI: 10.3987/com-18-s(f)58] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Miller SA, Bisset KA, Leadbeater NE, Eddy NA. Catalytic Oxidation of Alcohols Using a 2,2,6,6-Tetramethylpiperidine-N
-hydroxyammonium Cation. European J Org Chem 2018. [DOI: 10.1002/ejoc.201801718] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Shelli A. Miller
- Department of Chemistry; University of Connecticut; 55 North Eagleville Road Storrs Connecticut 06269 USA
| | - Kathryn A. Bisset
- Department of Chemistry; University of Connecticut; 55 North Eagleville Road Storrs Connecticut 06269 USA
| | - Nicholas E. Leadbeater
- Department of Chemistry; University of Connecticut; 55 North Eagleville Road Storrs Connecticut 06269 USA
| | - Nicholas A. Eddy
- Department of Chemistry; University of Connecticut; 55 North Eagleville Road Storrs Connecticut 06269 USA
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Akagawa K, Kudo K. Development of Selective Peptide Catalysts with Secondary Structural Frameworks. Acc Chem Res 2017; 50:2429-2439. [PMID: 28872296 DOI: 10.1021/acs.accounts.7b00211] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Enzymes are biogenic catalysts that enable the vital activity of organisms. Enzymes promote reactions in a selective manner with a high level of substrate recognition ability. The development of such a sophisticated catalyst has been one of the goals for chemists. A synthetic peptide is the prime candidate to realize an enzyme-like catalyst. Considering that the catalytic function of enzymes derives from their molecular structures, the key for the creation of a peptide catalyst might be the introduction of a specific three-dimensional structure. Our motivation was to find a peptide catalyst with a versatile secondary structural framework and apply the peptide to a variety of selective reactions. Although helical-peptide-catalyzed asymmetric epoxidation of enones is popular, no other highly enantioselective reaction with a helical peptide has been reported. It was found that resin-supported α-helical polyleucine promoted asymmetric conjugate addition of a carbon nucleophile to enones via the formation of an iminium intermediate at the N-terminal amino group. By changing the helical chain to a repetitive Leu-Leu-Aib (Aib = α-aminoisobutyric acid) sequence and introducing a few amino acids to the N-terminus, a highly enantioselective peptide catalyst was obtained. The helical peptide catalyst was applicable for a tandem enamine/iminium-mediated reaction and asymmetric epoxidation of enones. Although the extension of the helical peptide to conjugate addition of a nucleophile to an enal was not successful simply by attaching proline to the N-terminus of the helix, the incorporation of a β-turn motif was effective to improve the catalytic performance. In the sequence of such a turn-helix-type peptide, the helical part was seemingly distant from the N-terminal amino group; however, the hydrophobicity, structure, and chirality of the helix largely affected the reaction. The turn-helix-type peptide promoted a wide range of asymmetric reactions: conjugated additions of hydride and carbon nucleophiles to enals via the iminium activation and α-oxyamination of aldehydes via the enamine activation. The peptides with turn-helix and helix frameworks were also employed for several reactions that were difficult to achieve with low-molecular-weight catalysts: enzyme-cocatalyzed asymmetric oxidation in water, diastereo- and enantioselective cyclopropanation, regioselective reduction of dienals, kinetic resolution of planar-chiral compounds, and desymmetrization to induce planar chirality. To explore other types of peptide catalysts, a combinatorial library screening was performed. On the way, it was revealed that a histidyl residue assisted to accelerate a reaction via reversible addition to an iminium intermediate. Through the screening of random peptide libraries, novel peptide sequences for efficient and enantioselective conjugate addition were discovered. Although we have no information about the molecular structure of the newly found peptides, they can be an entry point for establishing a versatile framework of peptide catalysts.
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Affiliation(s)
- Kengo Akagawa
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Kazuaki Kudo
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
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10
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Taninokuchi S, Yazaki R, Ohshima T. Catalytic Aerobic Chemoselective α-Oxidation of Acylpyrazoles en Route to α-Hydroxy Acid Derivatives. Org Lett 2017; 19:3187-3190. [DOI: 10.1021/acs.orglett.7b01293] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Seiya Taninokuchi
- Graduate School of Pharmaceutical
Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Ryo Yazaki
- Graduate School of Pharmaceutical
Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Takashi Ohshima
- Graduate School of Pharmaceutical
Sciences, Kyushu University, Fukuoka 812-8582, Japan
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11
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Organocatalysis and Biocatalysis Hand in Hand: Combining Catalysts in One-Pot Procedures. Adv Synth Catal 2017. [DOI: 10.1002/adsc.201700158] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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12
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Schrittwieser JH, Velikogne S, Hall M, Kroutil W. Artificial Biocatalytic Linear Cascades for Preparation of Organic Molecules. Chem Rev 2017; 118:270-348. [DOI: 10.1021/acs.chemrev.7b00033] [Citation(s) in RCA: 371] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Joerg H. Schrittwieser
- Institute
of Chemistry, Organic and Bioorganic Chemistry, University of Graz, NAWI Graz, BioTechMed Graz, Heinrichstrasse 28, 8010 Graz, Austria
| | - Stefan Velikogne
- ACIB
GmbH, Department of Chemistry, University of Graz, Heinrichstrasse
28, 8010 Graz, Austria
| | - Mélanie Hall
- Institute
of Chemistry, Organic and Bioorganic Chemistry, University of Graz, NAWI Graz, BioTechMed Graz, Heinrichstrasse 28, 8010 Graz, Austria
| | - Wolfgang Kroutil
- Institute
of Chemistry, Organic and Bioorganic Chemistry, University of Graz, NAWI Graz, BioTechMed Graz, Heinrichstrasse 28, 8010 Graz, Austria
- ACIB
GmbH, Department of Chemistry, University of Graz, Heinrichstrasse
28, 8010 Graz, Austria
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Gómez-Palomino A, Pellicena M, Romo JM, Solà R, Romea P, Urpí F, Font-Bardia M. Stereoselective Aminoxylation of Biradical Titanium Enolates with TEMPO. Chemistry 2014; 20:10153-9. [DOI: 10.1002/chem.201402127] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Indexed: 10/25/2022]
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14
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Liang X, Li N, Chen X, Su W. Asymmetric α-oxyamination of aldehydes by synergistic catalysis of imidazolethiones and metal salts. RSC Adv 2014. [DOI: 10.1039/c4ra08556f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The novel and efficient imidazolethione catalysts combined with metal salts were successfully introduced to the asymmetric α-oxyamination of aldehydes.
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Affiliation(s)
- Xianrui Liang
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals
- College of Pharmaceutical Sciences
- Zhejiang University of Technology
- Hangzhou 310014, China
| | - Na Li
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals
- College of Pharmaceutical Sciences
- Zhejiang University of Technology
- Hangzhou 310014, China
| | - Xinlei Chen
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals
- College of Pharmaceutical Sciences
- Zhejiang University of Technology
- Hangzhou 310014, China
| | - Weike Su
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals
- College of Pharmaceutical Sciences
- Zhejiang University of Technology
- Hangzhou 310014, China
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15
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Duschmalé J, Kohrt S, Wennemers H. Peptide catalysis in aqueous emulsions. Chem Commun (Camb) 2014; 50:8109-12. [DOI: 10.1039/c4cc01759e] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Drouet F, Zhu J, Masson G. Iron Chloride‐Catalyzed Three‐Component Domino Sequences: Syntheses of Functionalized α‐Oxy‐N‐acylhemiaminals and α‐Oxyimides. Adv Synth Catal 2013. [DOI: 10.1002/adsc.201300847] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Fleur Drouet
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles, CNRS, 91198 Gif‐sur‐Yvette Cedex, France, homepage: http://www.icsn.cnrs‐gif.fr/spip.php?article225
| | - Jieping Zhu
- Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), EPFL‐SB‐ISIC LSPN, CH‐1015 Lausanne, Switzerland
| | - Géraldine Masson
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles, CNRS, 91198 Gif‐sur‐Yvette Cedex, France, homepage: http://www.icsn.cnrs‐gif.fr/spip.php?article225
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Kano T, Shirozu F, Maruoka K. Metal-Free Enantioselective Hydroxyamination of Aldehydes with Nitrosocarbonyl Compounds Catalyzed by an Axially Chiral Amine. J Am Chem Soc 2013; 135:18036-9. [DOI: 10.1021/ja4099627] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Taichi Kano
- Department
of Chemistry,
Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Fumitaka Shirozu
- Department
of Chemistry,
Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Keiji Maruoka
- Department
of Chemistry,
Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
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18
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Kano T, Maruoka K. Unique properties of chiral biaryl-based secondary aminecatalysts for asymmetric enamine catalysis. Chem Sci 2013. [DOI: 10.1039/c2sc21612d] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Akagawa K, Kudo K. Asymmetric induction by helical poly(amino acid)s in cyanosilylation of aldehydes. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.07.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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20
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Ho XH, Oh HJ, Jang HY. Multistep Organocatalysis for the Asymmetric Synthesis of Multisubstituted Aldehydes from Allylic Alcohols. European J Org Chem 2012. [DOI: 10.1002/ejoc.201200863] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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21
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Akagawa K, Umezawa R, Kudo K. Asymmetric one-pot sequential Friedel-Crafts-type alkylation and α-oxyamination catalyzed by a peptide and an enzyme. Beilstein J Org Chem 2012; 8:1333-7. [PMID: 23019467 PMCID: PMC3458757 DOI: 10.3762/bjoc.8.152] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 07/17/2012] [Indexed: 01/04/2023] Open
Abstract
In the presence of a peptide catalyst and the oxidative enzyme laccase, a one-pot sequential reaction including a Friedel–Crafts-type alkylation of α,β-unsaturated aldehydes followed by an α-oxyamination was realized. The reaction in aqueous solvent to promote the enzymatic oxidation, and the use of a peptide catalyst compatible with such conditions, were essential. The present sequential reaction afforded oxygen-functionalized indole or pyrrole derivatives in a highly enantioselective manner.
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Affiliation(s)
- Kengo Akagawa
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
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22
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Li Y, Pouliot M, Vogler T, Renaud P, Studer A. α-Aminoxylation of ketones and β-chloro-α-aminoxylation of enones with TEMPO and chlorocatecholborane. Org Lett 2012; 14:4474-7. [PMID: 22900473 DOI: 10.1021/ol301979b] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxidation of various cyclic and acyclic ketones under mild conditions with chlorocatecholborane, a bulky pyridine base, and TEMPO to the corresponding α-aminoxylated products in good to excellent yields (52-99%) is described. For enones as substrates, products of a β-chloro-α-aminoxylation are obtained (70-89%).
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Affiliation(s)
- Yi Li
- Institute of Organic Chemistry, University of Münster, Corrensstrasse 40, 48149 Münster, Germany
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Dinca E, Hartmann P, Smrček J, Dix I, Jones PG, Jahn U. General and Efficient α-Oxygenation of Carbonyl Compounds by TEMPO Induced by Single-Electron-Transfer Oxidation of Their Enolates. European J Org Chem 2012. [DOI: 10.1002/ejoc.201200736] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Akagawa K, Suzuki R, Kudo K. Effect of the Helical Tether of a Resin-Supported Peptide Catalyst for Friedel-Crafts-Type Alkylation in Water. Adv Synth Catal 2012. [DOI: 10.1002/adsc.201100950] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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25
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Simonovich SP, Van Humbeck JF, MacMillan DWC. A general approach to the enantioselective α-oxidation of aldehydes via synergistic catalysis. Chem Sci 2012; 3:58-61. [PMID: 22308217 PMCID: PMC3269783 DOI: 10.1039/c1sc00556a] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A new enantioselective α-oxidation of aldehydes has been accomplished using TEMPO and a synergistic combination of copper and organic catalysis. Expanding upon recently reported mechanistic studies, these mild catalytic conditions provide stable aldehyde products bearing a wide array of electronically and sterically diverse substructures. The utility of these oxidized products is highlighted by subsequent derivatization to a variety of common chiral synthons, without loss in enantiopurity.
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Affiliation(s)
- Scott P. Simonovich
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey, 08544, USA; Fax: +1 609 2585922; Tel: +1 609 2582254
| | - Jeffrey F. Van Humbeck
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey, 08544, USA; Fax: +1 609 2585922; Tel: +1 609 2582254
| | - David W. C. MacMillan
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey, 08544, USA; Fax: +1 609 2585922; Tel: +1 609 2582254
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Akagawa K, Sugiyama M, Kudo K. Asymmetric Michael addition of boronic acids to a γ-hydroxy-α,β-unsaturated aldehyde catalyzed by resin-supported peptide. Org Biomol Chem 2012; 10:4839-43. [DOI: 10.1039/c2ob25431j] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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