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Mulks FF, Pinho B, Platten AW, Andalibi MR, Expósito AJ, Edler KJ, Hevia E, Torrente-Murciano L. Continuous, stable, and safe organometallic reactions in flow at room temperature assisted by deep eutectic solvents. Chem 2022. [DOI: 10.1016/j.chempr.2022.11.004] [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]
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Simoens A, Scattolin T, Cauwenbergh T, Pisanò G, Cazin CSJ, Stevens CV, Nolan SP. Continuous Flow Synthesis of Metal–NHC Complexes**. Chemistry 2021; 27:5653-5657. [DOI: 10.1002/chem.202100190] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 01/29/2021] [Indexed: 01/01/2023]
Affiliation(s)
- Andreas Simoens
- Department of Green Chemistry and Technology Synthesis Bioresources and Bioorganic Chemistry Research Group Ghent University Coupure Links 653 9000 Ghent Belgium
| | - Thomas Scattolin
- Department of Chemistry and Centre for Sustainable Chemistry Ghent University Krijgslaan 281,S-3 9000 Ghent Belgium
| | - Thibault Cauwenbergh
- Department of Chemistry and Centre for Sustainable Chemistry Ghent University Krijgslaan 281,S-3 9000 Ghent Belgium
| | - Gianmarco Pisanò
- Department of Chemistry and Centre for Sustainable Chemistry Ghent University Krijgslaan 281,S-3 9000 Ghent Belgium
| | - Catherine S. J. Cazin
- Department of Chemistry and Centre for Sustainable Chemistry Ghent University Krijgslaan 281,S-3 9000 Ghent Belgium
| | - Christian V. Stevens
- Department of Green Chemistry and Technology Synthesis Bioresources and Bioorganic Chemistry Research Group Ghent University Coupure Links 653 9000 Ghent Belgium
| | - Steven P. Nolan
- Department of Chemistry and Centre for Sustainable Chemistry Ghent University Krijgslaan 281,S-3 9000 Ghent Belgium
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Fortunato M, Gimbert Y, Rousset E, Lameiras P, Martinez A, Gatard S, Plantier-Royon R, Jaroschik F. Diastereoselective Synthesis of Axially Chiral Xylose-Derived 1,3-Disubstituted Alkoxyallenes: Scope, Structure, and Mechanism. J Org Chem 2020; 85:10681-10694. [DOI: 10.1021/acs.joc.0c01240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Moustapha Fortunato
- Institut de Chimie Moléculaire de Reims, UMR CNRS 7312, Université de Reims Champagne-Ardenne, 51687 Reims, France
| | - Yves Gimbert
- Département de Chimie Moléculaire, UMR CNRS 5250, Université Grenoble Alpes, 38058 Grenoble, France
| | - Elodie Rousset
- Institut de Chimie Moléculaire de Reims, UMR CNRS 7312, Université de Reims Champagne-Ardenne, 51687 Reims, France
| | - Pedro Lameiras
- Institut de Chimie Moléculaire de Reims, UMR CNRS 7312, Université de Reims Champagne-Ardenne, 51687 Reims, France
| | - Agathe Martinez
- Institut de Chimie Moléculaire de Reims, UMR CNRS 7312, Université de Reims Champagne-Ardenne, 51687 Reims, France
| | - Sylvain Gatard
- Institut de Chimie Moléculaire de Reims, UMR CNRS 7312, Université de Reims Champagne-Ardenne, 51687 Reims, France
| | - Richard Plantier-Royon
- Institut de Chimie Moléculaire de Reims, UMR CNRS 7312, Université de Reims Champagne-Ardenne, 51687 Reims, France
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Abstract
Alkoxyallenes are easily available and versatile building blocks for the preparation
of a variety of natural products (terpenes, polyketides, alkaloids, amino acids, carbohydrates
etc.) originating from different classes. The synthetic use of the three allene carbon
atoms frequently follows the “normal” reactivity pattern showing that alkoxyallenes
can be regarded as special enol ethers. Additions of alcohols or amines to alkoxyallenes
form vinyl-substituted O,O- or N,O-acetals that are frequently used in ring-closing
metathesis reactions. This methodology delivers crucial heterocyclic units of the target
compounds. Enantioselective additions provide products with high enantiopurity.
Alternatively, an “Umpolung” of reactivity of alkoxyallenes is achieved by lithiation at
C-1 and subsequent reaction with electrophiles, such as alkyl halides, carbonyl
compounds, imines or nitrones. High stereoselectivity of the addition step can be achieved by substrate control
or auxiliary control. The high diastereo- or enantioselectivity is transferred to the subsequent acyclic or cyclic
products. The cyclization of primary addition products occurs efficiently under mild conditions and provides
functionalized dihydrofuran, dihydropyrrole or 1,2-oxazine derivatives. These are valuable intermediates for
the synthesis of a variety of heterocyclic natural products. Nazarov cyclizations or gold catalyzed rearrangements
allow the synthesis of five- and six-membered carbocyclic compounds that are also used for natural
product synthesis.
Dedicated to Dr. Reinhold Zimmer, a pioneer of alkoxyallene chemistry, on the occasion of his 60th
birthday.
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Affiliation(s)
- Volker Martin Schmiedel
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | - Hans-Ulrich Reissig
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
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Colella M, Nagaki A, Luisi R. Flow Technology for the Genesis and Use of (Highly) Reactive Organometallic Reagents. Chemistry 2019; 26:19-32. [PMID: 31498924 DOI: 10.1002/chem.201903353] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/07/2019] [Indexed: 12/25/2022]
Abstract
In the field of organic synthesis, the advent of flow chemistry and flow microreactor technology represented a tremendous novelty in the way of thinking and performing chemical reactions, opening the doors to poorly explored or even impossible transformations using batch methods. In this Concept article, we would like to highlight the impact of flow chemistry for exploiting highly reactive organometallic reagents, and how, alongside the well-known advantages concerning safety, scalability, and productivity, flow chemistry makes possible processes that are impossible to control by using the traditional batch approach.
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Affiliation(s)
- Marco Colella
- Department of Pharmacy-Drug Sciences, Flow Chemistry and Microreactor Technology FLAME-Lab, University of Bari "A. Moro", Via E. Orabona 4, Bari, 70125, Italy
| | - Aichiiro Nagaki
- Department of Synthetic and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Renzo Luisi
- Department of Pharmacy-Drug Sciences, Flow Chemistry and Microreactor Technology FLAME-Lab, University of Bari "A. Moro", Via E. Orabona 4, Bari, 70125, Italy
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Lechel T, Kumar R, Bera MK, Zimmer R, Reissig HU. The LANCA three-component reaction to highly substituted β-ketoenamides - versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives. Beilstein J Org Chem 2019; 15:655-678. [PMID: 30931007 PMCID: PMC6423578 DOI: 10.3762/bjoc.15.61] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 02/20/2019] [Indexed: 11/23/2022] Open
Abstract
The LANCA three-component reaction of lithiated alkoxyallenes LA, nitriles N and carboxylic acids CA leads to β-ketoenamides KE in good to excellent yields. The scope of this reaction is very broad and almost all types of nitriles and carboxylic acids have successfully been used. The alkoxy group introduced via the allene component is also variable and hence the subsequent transformation of this substituent into a hydroxy group can be performed under different conditions. Enantiopure nitriles or carboxylic acids can also be employed leading to chiral KE with high enantiopurity and dinitriles or dicarboxylic acids also lead to the expected bis-β-ketoenamides. β-Ketoenamides incorporate a unique combination of functional groups and hence a manifold of subsequent reactions to highly substituted heterocyclic compounds is possible. An intramolecular aldol-type condensation reaction efficiently furnishes pyridin-4-ols PY that can be further modified by palladium-catalyzed reactions, e.g., to specifically substituted furopyridine derivatives. Condensations of β-ketoenamides with ammonium salts or with hydroxylamine hydrochloride afford pyrimidines PM or pyrimidine N-oxides PO with a highly flexible substitution pattern in good yields. The functional groups of these heterocycles also allow a variety of subsequent reactions to various pyrimidine derivatives. On the other hand, acid-labile alkoxy substituents such as a 2-(trimethylsilyl)ethoxy group are required for the conversion of β-ketoenamides into 5-acetyl-substituted oxazoles OX, again compounds with high potential for subsequent functional group transformations. For acid labile β-ketoenamides bearing bulky substituents the acid treatment leads to acylamido-substituted 1,2-diketones DK that could be converted into quinoxalines QU. All classes of heterocycles accessed through the key β-ketoenamides show a unique substitution pattern - not easily accomplishable by alternative methods - and therefore many subsequent reactions are possible.
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Affiliation(s)
- Tilman Lechel
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany
| | - Roopender Kumar
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany.,Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW Cambridge, UK
| | - Mrinal K Bera
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany.,Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, PO-Botanic Garden, Howrah-711 103 (WB), India
| | - Reinhold Zimmer
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany
| | - Hans-Ulrich Reissig
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany
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