1
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Daniel FL, Srinivasan K. Intramolecular 1,2-Aroyl Migration in Spiro Donor-Acceptor Cyclopropanes: Formation of 1,4-Naphthoquinones and 1-Naphthols as Ring-Expansion Products. J Org Chem 2024; 89:5304-5313. [PMID: 38593430 DOI: 10.1021/acs.joc.3c02671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Most of the known rearrangement reactions of donor-acceptor cyclopropanes (DACs) involve the migration of cationic carbon atom to anionic carbon or heteroatoms in 1,3- or 1,4-positions. In the present work, we observed that spiro DACs based on 1,3-indanedione or 1-indanone moiety undergo intramolecular 1,2-aroyl migration when treated with titanium(IV) chloride to afford 1,4-naphthoquinones and α-naphthols readily. The reactions take place through the formation of putative 1,3-dipolar intermediates, followed by cleavage and migration of the aroyl group to the adjacent carbon to afford the ring-expansion products.
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Affiliation(s)
- Franklin Leslin Daniel
- School of Chemistry, Bharathidasan University, Tiruchirappalli, Tamil Nadu 620 024, India
| | - Kannupal Srinivasan
- School of Chemistry, Bharathidasan University, Tiruchirappalli, Tamil Nadu 620 024, India
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2
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Panahi F, Breit B. Rhodium-Catalyzed Asymmetric Macrocyclization towards Crown Ethers Using Hydroamination of Bis(allenes). Angew Chem Int Ed Engl 2024; 63:e202317981. [PMID: 38323896 DOI: 10.1002/anie.202317981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 02/06/2024] [Accepted: 02/06/2024] [Indexed: 02/08/2024]
Abstract
Enantiomerically enriched crown ethers (CE) exhibit strong asymmetric induction in phase transfer catalysis, supramolecular catalysis and molecular recognition processes. Traditional methods have often been used to access these valuable compounds, which limit their diversity and consequently their applicability. Herein, a practical catalytic method is described for the gram scale synthesis of a class of chiral CEs (aza-crown ethers; ACEs) using Rh-catalyzed hydroamination of bis(allenes) with diamines. Using this approach, a wide range of chiral vinyl functionalized CEs with ring sizes ranging from 12 to 36 have been successfully prepared in high yields of up to 92 %, dr of up to >20 : 1 and er of up to >99 : 1. These vinyl substituted CEs allow for further diversification giving facile access to various CE derivatives as well as to their three-dimensional analogues using ring-closing metathesis. Some of these chiral CEs themselves display high potential for use in asymmetric catalysis.
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Affiliation(s)
- Farhad Panahi
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg im Breisgau, Germany
| | - Bernhard Breit
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104, Freiburg im Breisgau, Germany
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3
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Traboni S, Bedini E, Capasso D, Esposito F, Iadonisi A. Adaptation of Zemplén's conditions for a simple and highly selective approach to methyl 1,2-trans glycosides. Carbohydr Res 2023; 528:108824. [PMID: 37141732 DOI: 10.1016/j.carres.2023.108824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 04/18/2023] [Accepted: 04/20/2023] [Indexed: 05/06/2023]
Abstract
1,2-trans methyl glycosides can be readily obtained from peracetylated sugars through their initial conversion into glycosyl iodide donors and subsequent exposure of these latter to a slight excess of sodium methoxide in methanol. Under these conditions a varied set of mono- and disaccharide precursors afforded the corresponding 1,2-trans glycosides with concomitant de-O-acetylation in satisfying yields (in the range 59-81%). A similar approach also proved effective when using GlcNAc glycosyl chloride as the donor.
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Affiliation(s)
- Serena Traboni
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 4, 80126, Naples, Italy
| | - Emiliano Bedini
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 4, 80126, Naples, Italy
| | - Domenica Capasso
- Center for Life Sciences and Technologies (CESTEV), University of Naples Federico II, 80145, Naples, Italy
| | - Fabiana Esposito
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 4, 80126, Naples, Italy
| | - Alfonso Iadonisi
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 4, 80126, Naples, Italy.
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4
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Semproli R, Simona Robescu M, Sangiorgio S, Pargoletti E, Bavaro T, Rabuffetti M, Cappelletti G, Speranza G, Ubiali D. From Lactose to Alkyl Galactoside Fatty Acid Esters as Non-Ionic Biosurfactants: A Two-Step Enzymatic Approach to Cheese Whey Valorization. Chempluschem 2023; 88:e202200331. [PMID: 36592040 DOI: 10.1002/cplu.202200331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/08/2022] [Indexed: 12/14/2022]
Abstract
A library of alkyl galactosides was synthesized to provide the "polar head" of sugar fatty acid esters to be tested as non-ionic surfactants. The enzymatic transglycosylation of lactose resulted in alkyl β-D-galactopyranosides, whereas the Fischer glycosylation of galactose afforded isomeric mixtures of α- and β-galactopyranosides and α- and β-galactofuranosides. n-Butyl galactosides from either routes were enzymatically esterified with palmitic acid, used as the fatty acid "tail" of the surfactant, giving the corresponding n-butyl 6-O-palmitoyl-galactosides. Measurements of interfacial tension and emulsifying properties of n-butyl 6-O-palmitoyl-galactosides revealed that the esters of galactopyranosides are superior to those of galactofuranosides, and that the enantiopure n-butyl 6-O-palmitoyl-β-D-galactoside, prepared by the fully enzymatic route, leads to the most stable emulsion. These results pave the way to the use of lactose-rich cheese whey as raw material for the obtainment of bio-based surfactants.
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Affiliation(s)
- Riccardo Semproli
- Department of Drug Sciences, University of Pavia, Viale Taramelli 12, Pavia, I-27100, Italy
| | - Marina Simona Robescu
- Department of Drug Sciences, University of Pavia, Viale Taramelli 12, Pavia, I-27100, Italy
| | - Sara Sangiorgio
- Department of Chemistry, University of Milano, Via Golgi 19, Milano, I-20133, Italy
| | - Eleonora Pargoletti
- Department of Chemistry, University of Milano, Via Golgi 19, Milano, I-20133, Italy
| | - Teodora Bavaro
- Department of Drug Sciences, University of Pavia, Viale Taramelli 12, Pavia, I-27100, Italy
| | - Marco Rabuffetti
- Department of Chemistry, University of Milano, Via Golgi 19, Milano, I-20133, Italy
| | - Giuseppe Cappelletti
- Department of Chemistry, University of Milano, Via Golgi 19, Milano, I-20133, Italy
| | - Giovanna Speranza
- Department of Chemistry, University of Milano, Via Golgi 19, Milano, I-20133, Italy
| | - Daniela Ubiali
- Department of Drug Sciences, University of Pavia, Viale Taramelli 12, Pavia, I-27100, Italy
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5
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Lops C, Pengo P, Pasquato L. Highly Efficient Darzens Reactions Mediated by Phosphazene Bases under Mild Conditions. Chemistry 2022; 11:e202200179. [PMID: 36207800 PMCID: PMC9547082 DOI: 10.1002/open.202200179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 08/30/2022] [Indexed: 11/18/2022]
Abstract
The highly basic and poorly nucleophilic phosphazene base P1‐t‐Bu promotes the Darzens condensation of α‐halo esters with aromatic aldehydes affording α,β‐epoxy esters in nearly quantitative yields under mild conditions and in short reaction times. The more basic P4‐t‐Bu phosphazene was found useful with low reactivity aldehydes. These reactions can be performed in aprotic organic solvents of low polarity, thus minimizing the hydrolysis of α,β‐epoxy esters which often accompanies the base‐promoted Darzens condensations.
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Affiliation(s)
- Carmine Lops
- Department of Chemical and Pharmaceutical SciencesUniversity of TriesteVia L. Giorgieri 134127TriesteItaly,Aptuit – an Evotec CompanyVia A. Fleming 437135VeronaItaly
| | - Paolo Pengo
- Department of Chemical and Pharmaceutical SciencesUniversity of TriesteVia L. Giorgieri 134127TriesteItaly
| | - Lucia Pasquato
- Department of Chemical and Pharmaceutical SciencesUniversity of TriesteVia L. Giorgieri 134127TriesteItaly
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6
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Hao ZF, Zhu SJ, Hao YJ, Zhang WH, Zhou Y, Tian YP, Lei CW. Enantioselective Synthesis of Bispiro[indanedione-oxindole-cyclopropane]s through Organocatalytic [2+1] Cycloaddition. J Org Chem 2022. [PMID: 35960861 DOI: 10.1021/acs.joc.2c01009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A series of compounds featuring a novel bispiro[indanedione-oxindole-cyclopropane] moiety have been synthesized through a squaramide-catalyzed [2+1] cycloaddition reaction. The tandem Michael-alkylation reaction of 2-arylidene-1,3-indanediones with 3-bromooxindoles furnished the cycloadducts in high yields with excellent diastereo- and enantioselectivities. The ammonium ylide in the catalytic process, as a key intermediate, was revealed by the high-resolution mass spectrometry study.
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Affiliation(s)
- Zhi-Feng Hao
- School of Pharmacy, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, China
| | - Shi-Jie Zhu
- School of Pharmacy, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, China
| | - Yong-Jia Hao
- School of Pharmacy, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, China
| | - Wen-Hui Zhang
- School of Pharmacy, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, China
| | - Ying Zhou
- School of Pharmacy, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, China
| | - You-Ping Tian
- School of Pharmacy, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, China
| | - Chuan-Wen Lei
- School of Pharmacy, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, China
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7
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Singh SK, Mishra N, Kumar S, Jaiswal MK, Tiwari VK. Growing Impact of Carbohydrate‐Based Organocatalysts. ChemistrySelect 2022. [DOI: 10.1002/slct.202201314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Sumit K. Singh
- Department of Chemistry Institute of Science Banaras Hindu University Varanasi 221005 INDIA
| | - Nidhi Mishra
- Department of Chemistry Institute of Science Banaras Hindu University Varanasi 221005 INDIA
| | - Sunil Kumar
- Department of Chemistry Institute of Science Banaras Hindu University Varanasi 221005 INDIA
| | - Manoj K. Jaiswal
- Department of Chemistry Institute of Science Banaras Hindu University Varanasi 221005 INDIA
| | - Vinod K. Tiwari
- Department of Chemistry Institute of Science Banaras Hindu University Varanasi 221005 INDIA
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8
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Orbán I, Varga B, Bagi P, Holczbauer T, Rapi Z. Enantioselective Cyclopropanation of 2‐Cyano‐3‐arylacrylates Using Carbohydrate‐based Crown Ethers. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- István Orbán
- Budapest University of Technology and Economics: Budapesti Muszaki es Gazdasagtudomanyi Egyetem Department of Organic Chemistry and Technology HUNGARY
| | - Bertalan Varga
- Budapest University of Technology and Economics: Budapesti Muszaki es Gazdasagtudomanyi Egyetem Department of Organic Chemistry and Technology HUNGARY
| | - Péter Bagi
- Budapest University of Technology and Economics: Budapesti Muszaki es Gazdasagtudomanyi Egyetem Department of Organic Chemistry and Technology HUNGARY
| | - Tamás Holczbauer
- Eötvös Loránd Research Network Research Centre for Natural Sciences Chemical Crystallography Research Laboratory and Institute of Organic Chemistry HUNGARY
| | - Zsolt Rapi
- Budapest University of Technology and Economics: Budapesti Muszaki es Gazdasagtudomanyi Egyetem Department of Organic Chemistry and Technology Műegyetem rkp. 3. 1111 Budapest HUNGARY
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9
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Wojaczyńska E, Steppeler F, Iwan D, Scherrmann MC, Marra A. Synthesis and Applications of Carbohydrate-Based Organocatalysts. Molecules 2021; 26:7291. [PMID: 34885873 PMCID: PMC8659088 DOI: 10.3390/molecules26237291] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 12/22/2022] Open
Abstract
Organocatalysis is a very useful tool for the asymmetric synthesis of biologically or pharmacologically active compounds because it avoids the use of noxious metals, which are difficult to eliminate from the target products. Moreover, in many cases, the organocatalysed reactions can be performed in benign solvents and do not require anhydrous conditions. It is well-known that most of the above-mentioned reactions are promoted by a simple aminoacid, l-proline, or, to a lesser extent, by the more complex cinchona alkaloids. However, during the past three decades, other enantiopure natural compounds, the carbohydrates, have been employed as organocatalysts. In the present exhaustive review, the detailed preparation of all the sugar-based organocatalysts as well as their catalytic properties are described.
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Affiliation(s)
- Elżbieta Wojaczyńska
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50 370 Wrocław, Poland
| | - Franz Steppeler
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50 370 Wrocław, Poland
| | - Dominika Iwan
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50 370 Wrocław, Poland
| | - Marie-Christine Scherrmann
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Saclay, Bâtiment 420, 91405 Orsay, France
| | - Alberto Marra
- Institut des Biomolécules Max Mousseron (IBMM-UMR 5247), Université de Montpellier, Pôle Chimie Balard Recherche, 1919 Route de Mende, 34293 Montpellier, France
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10
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Orbán I, Varga B, Bagi P, Hegedűs L, Bakó P, Rapi Z. Synthesis of Methyl 4,6-Di- O-ethyl-α-d-glucopyranoside-Based Azacrown Ethers and Their Effects in Asymmetric Reactions. Molecules 2021; 26:4668. [PMID: 34361821 PMCID: PMC8348128 DOI: 10.3390/molecules26154668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 07/25/2021] [Accepted: 07/29/2021] [Indexed: 12/01/2022] Open
Abstract
Carbohydrate-based crown ethers have been reported to be able to generate asymmetric induction in certain reactions. Previously, it was proved that the monosaccharide unit, the anomeric substituent, and the sidearm could influence the catalytic activity of the monoaza-15-crown-5 macrocycles derived from sugars. In order to gain information about the effect of the flexibility, 4,6-di-O-ethyl-glucoside-based crown compounds were synthesized, and their efficiency was compared to the 4,6-O-benzylidene analogues. It was found that the absence of the two-ring annulation has a negative effect on the enantioselectivity in liquid-liquid two-phase reactions: in the Darzens condensation of 2-chloroacetophenone and in the epoxidation of chalcone. The same trend was observed in the solid-liquid phase Michael addition of diethyl acetamidomalonate. Surprisingly, in the solid-liquid phase cyclopropanation of benzylidenemalononitrile, one of the new catalysts was highly enantioselective (99% ee).
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Affiliation(s)
| | | | | | | | | | - Zsolt Rapi
- Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, H-1111 Budapest, Hungary; (I.O.); (B.V.); (P.B.); (L.H.); (P.B.)
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11
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Zhang Z, Shao Y, Tang J, Jiang J, Wang L, Li S. Supramolecular asymmetric catalysis mediated by crown ethers and related recognition systems. GREEN SYNTHESIS AND CATALYSIS 2021. [DOI: 10.1016/j.gresc.2021.03.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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12
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Abstract
Carbohydrate-based crown ethers represent a special group of chiral phase transfer catalysts. Several derivatives of these macrocycles have been synthesized in our research group. Among these compounds, monoaza-15-crown-5 lariat ethers proved to be effective phase transfer and enantioselective catalysts in certain reactions. Those chiral azacrown ethers incorporating various carbohydrate moieties in the macrocyclic structure are reviewed, which generated asymmetric induction in reactions, such as Michael addition, epoxidation of enones, Darzens condensation and Michael-initiated ring-closure (MIRC) reaction. Effects on the catalytic activity of the structural changes are the focus.
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13
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Novel polymer crafted sugar thiacrown ether and its applications in recovery of metal ions. Carbohydr Res 2020; 495:108057. [DOI: 10.1016/j.carres.2020.108057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/22/2020] [Accepted: 06/01/2020] [Indexed: 11/22/2022]
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14
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Capocasa G, Di Berto Mancini M, Frateloreto F, Lanzalunga O, Olivo G, Di Stefano S. Easy Synthesis of a Self-Assembled Imine-Based Iron(II) Complex Endowed with Crown-Ether Receptors. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Giorgio Capocasa
- Dipartimento di Chimica; Università di Roma “La Sapienza”; and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione; P.le A. Moro 5 00185 Roma Italy
| | - Marika Di Berto Mancini
- Dipartimento di Chimica; Università di Roma “La Sapienza”; and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione; P.le A. Moro 5 00185 Roma Italy
| | - Federico Frateloreto
- Dipartimento di Chimica; Università di Roma “La Sapienza”; and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione; P.le A. Moro 5 00185 Roma Italy
| | - Osvaldo Lanzalunga
- Dipartimento di Chimica; Università di Roma “La Sapienza”; and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione; P.le A. Moro 5 00185 Roma Italy
| | - Giorgio Olivo
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; Campus de Montilivi 17003 Girona Spain
| | - Stefano Di Stefano
- Dipartimento di Chimica; Università di Roma “La Sapienza”; and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione; P.le A. Moro 5 00185 Roma Italy
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Homberg A, Lacour J. From reactive carbenes to chiral polyether macrocycles in two steps - synthesis and applications made easy? Chem Sci 2020; 11:6362-6369. [PMID: 34094103 PMCID: PMC8152409 DOI: 10.1039/d0sc01011a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 03/11/2020] [Indexed: 12/26/2022] Open
Abstract
Chiral polyether macrocycles are versatile molecules. For their preparation, original two-step procedures were recently developed and present the advantages of high concentration conditions and simple starting reagents (stable diazo reagents, small cyclic ethers, aliphatic or aromatic amines). Enantiopure materials are readily afforded by CSP-HPLC on a semi-preparative scale. Flexibility and adaptability in the macrocyclic design are provided by a large selection of amines to choose from while the ring size and chemical nature are controlled by the choice of 5 to 7-membered cyclic ether precursors. Such macrocycles have already been used as asymmetric catalysts, mono and ditopic receptors, fluorescent sensors and probes, and chiroptical reversible switches.
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Affiliation(s)
- Alexandre Homberg
- Department of Organic Chemistry, University of Geneva Quai Ernest Ansermet 30 1211 Geneva 4 Switzerland
| | - Jérôme Lacour
- Department of Organic Chemistry, University of Geneva Quai Ernest Ansermet 30 1211 Geneva 4 Switzerland
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16
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Di Stefano S, Capocasa G, Mandolini L. Supramolecular Catalysts Featuring Crown Ethers as Recognition Units. European J Org Chem 2020. [DOI: 10.1002/ejoc.201901914] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Stefano Di Stefano
- Dipartimento di Chimica; Università di Roma “La Sapienza”, and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione; P.le A. Moro 5 00185 Roma Italy
| | - Giorgio Capocasa
- Dipartimento di Chimica; Università di Roma “La Sapienza”, and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione; P.le A. Moro 5 00185 Roma Italy
| | - Luigi Mandolini
- Dipartimento di Chimica; Università di Roma “La Sapienza”, and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione; P.le A. Moro 5 00185 Roma Italy
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17
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Enantioselective cyclopropanation of conjugated cyanosulfones using carbohydrate-based crown ether catalysts. Tetrahedron 2020. [DOI: 10.1016/j.tet.2020.130965] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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18
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Homberg A, Hrdina R, Vishe M, Guénée L, Lacour J. Stereoselective deconjugation of macrocyclic α,β-unsaturated esters by sequential amidation and olefin transposition: application to enantioselective phase-transfer catalysis. Org Biomol Chem 2019; 17:6905-6910. [PMID: 31270519 DOI: 10.1039/c9ob01355e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The stereoselective synthesis of chiral macrocycles bearing two aliphatic amide functional groups is reported. After the amidation mediated by TBD, a guanidine derivative, the olefin transposition step is performed with a slight excess of t-BuOK. The products are afforded in moderate to good combined yields (up to 59%) and with an excellent syn diastereoselectivity (dr > 49 : 1). Introducing enantiopure α-branched substituents was possible and it resulted in mixtures of diastereomers, which could be tested as phase-transfer catalysts using the formation of a phenylalanine analog as a test reaction (up to 43% ee). A clear matched-mismatched situation was observed in the two diastereomeric series.
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Affiliation(s)
- Alexandre Homberg
- Department of Organic Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
| | - Radim Hrdina
- Department of Organic Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
| | - Mahesh Vishe
- Department of Organic Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
| | - Laure Guénée
- Laboratory of Crystallography, University of Geneva, Quai Ernest Ansermet 24, 1211 Geneva 4, Switzerland
| | - Jérôme Lacour
- Department of Organic Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
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