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Rozentsveig IB, Nikonova VS, Manuilov VV, Ushakov IA, Borodina TN, Smirnov VI, Korchevin NA. Heterocyclization of Bis(2-chloroprop-2-en-1-yl)sulfide in Hydrazine Hydrate–KOH: Synthesis of Thiophene and Pyrrole Derivatives. Molecules 2022; 27:molecules27206785. [PMID: 36296380 PMCID: PMC9609936 DOI: 10.3390/molecules27206785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 11/30/2022] Open
Abstract
The article is devoted to heterocyclization of bis(2-chloroprop-2-en-1-yl)sulfide which proceeds in hydrazine hydrate–alkali medium and leads to formation of thiophene and pyrrole derivatives: previously described 4,5,9,10-tetrahydrocycloocta[1,2-c;5,8-c’]dithiophene, as well as unknown hydrazone of 5-methylidene-3-methyldihydrothiophen-2-one and 1-amino-2-(propynylsulfanylpropenylsulfanyl)-3,5-dimethylpyrrole. Tentative mechanisms for the formation of the heterocyclic products are discussed. Obtained hydrazone of 5-methylidene-3-methyldihydrothiophen-2-one was used for the synthesis of a range of azine derivatives and in oxidation process with SeO2. The found reactions open up expedient approaches to the formation of various hardly accessible thiophene and pyrrole compounds from 2,3-dichloropropene and elemental sulfur as starting reagents.
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Affiliation(s)
- Igor B. Rozentsveig
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russia
- Chemistry Department, Irkutsk State University, Karl Marx Str., 1, 664003 Irkutsk, Russia
- Correspondence:
| | - Valentina S. Nikonova
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russia
| | - Victor V. Manuilov
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russia
| | - Igor A. Ushakov
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russia
| | - Tatyana N. Borodina
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russia
| | - Vladimir I. Smirnov
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russia
| | - Nikolay A. Korchevin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russia
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2
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Chemistry of Spontaneous Alkylation of Methimazole with 1,2-Dichloroethane. Molecules 2021; 26:molecules26227032. [PMID: 34834123 PMCID: PMC8625577 DOI: 10.3390/molecules26227032] [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: 10/11/2021] [Revised: 11/02/2021] [Accepted: 11/17/2021] [Indexed: 11/17/2022] Open
Abstract
Spontaneous S-alkylation of methimazole (1) with 1,2-dichloroethane (DCE) into 1,2-bis[(1-methyl-1H-imidazole-2-yl)thio]ethane (2), that we have described recently, opened the question about its formation pathway(s). Results of the synthetic, NMR spectroscopic, crystallographic and computational studies suggest that, under given conditions, 2 is obtained by direct attack of 1 on the chloroethyl derivative 2-[(chloroethyl)thio]-1-methyl-1H-imidazole (3), rather than through the isolated stable thiiranium ion isomer, i.e., 7-methyl-2H, 3H, 7H-imidazo[2,1-b]thiazol-4-ium chloride (4a, orthorhombic, space group Pnma), or in analogy with similar reactions, through postulated, but unproven intermediate thiiranium ion 5. Furthermore, in the reaction with 1, 4a prefers isomerization to the N-chloroethyl derivative, 1-chloroethyl-2,3-dihydro-3-methyl-1H-imidazole-2-thione (7), rather than alkylation to 2, while 7 further reacts with 1 to form 3-methyl-1-[(1-methyl-imidazole-2-yl)thioethyl]-1H-imidazole-2-thione (8, monoclinic, space group P 21/c). Additionally, during the isomerization of 3, the postulated intermediate thiiranium ion 5 was not detected by chromatographic and spectroscopic methods, nor by trapping with AgBF4. However, trapping resulted in the formation of the silver complex of compound 3, i.e., bis-{2-[(chloroethyl)thio]-1-methyl-1H-imidazole}-silver(I)tetrafluoroborate (6, monoclinic, space group P 21/c), which cyclized upon heating at 80 °C to 7-methyl-2H, 3H, 7H-imidazo[2,1-b]thiazol-4-ium tetrafluoroborate (4b, monoclinic, space group P 21/c). Finally, we observed thermal isomerization of both 2 and 2,3-dihydro-3-methyl-1-[(1-methyl-1H-imidazole-2-yl)thioethyl]-1H-imidazole-2-thione (8), into 1,2-bis(2,3-dihydro-3-methyl-1H-imidazole-2-thione-1-yl)ethane (9), which confirmed their structures.
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3
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Poleschner H, Seppelt K. Attempts to Synthesize a Thiirane, Selenirane, and Thiirene by Dealkylation of Chalcogeniranium and Thiirenium Salts. Chemistry 2021; 27:649-659. [PMID: 32737908 PMCID: PMC7821244 DOI: 10.1002/chem.202003461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Indexed: 02/05/2023]
Abstract
Thiiranium salts [Ad2 SR]+ X- (5, 8, 9, 11, 12; X- =Tf2 N- (Tf=CF3 SO2 ), SbCl6 - ) and seleniranium salts [Ad2 SeR]+ X- (14, 16, 17, 23-25; X- =Tf2 N- , BF4 - , CHB11 Cl11 - , SbCl6 - ) are synthesized from strained alkene bis(adamantylidene) (1). The disulfides and the diselenides (Me3 SiCH2 CH2 E)2 (4, 13), (tBuMe2 SiCH2 CH2 E)2 (7, 22), and (NCCH2 CH2 E)2 (10, 15; E=S, Se) have been used. The thiirenium salts [tBu2 C2 SR]+ X- (34) and [Ad2 C2 SR]+ X- (35, 36) are prepared from the bis-tert-butylacetylene (2) and bis-adamantyl-acetylene (3) with R=Me3 SiCH2 CH2 and tBuMe2 SiCH2 CH2 . Attempts to cleave off the groups Me3 SiCH2 CH2 , tBuMe2 SiCH2 CH2 , and NCCH2 CH2 resulted in thiiranes 27, 30. No selenirane Ad2 Se (33) is formed from seleniranium salts, instead cleavage to the alkene (1) and diselenide (13, 15) occurs. The thiirenium salt [Ad2 C2 SCH2 CH2 SiMe3 ]+ Tf2 N- (35) does not yield the thiirene Ad2 C2 S (37), the three-membered ring is cleaved, forming the alkyne (3) and disulfide (4). All compounds are characterized by ESI mass spectra, NMR spectra, and by quantum chemical calculations. Crystal structures of the salts 8, 12, 25, 17, 26, 36 and the thiiranes 27, 30 are presented.
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Affiliation(s)
- Helmut Poleschner
- Institut für Chemie und Biochemie, Anorganische ChemieFreie Universität BerlinFabeckstr. 34–3614195BerlinGermany
| | - Konrad Seppelt
- Institut für Chemie und Biochemie, Anorganische ChemieFreie Universität BerlinFabeckstr. 34–3614195BerlinGermany
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4
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Matviitsuk A, Panger JL, Denmark SE. Katalytische enantioselektive Sulfenofunktionalisierung von Alkenen: Entwicklung und aktuelle Fortschritte. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202005920] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Anastassia Matviitsuk
- Roger Adams Laboratory Department of Chemistry University of Illinois Urbana Illinois 61801 USA
| | - Jesse L. Panger
- Roger Adams Laboratory Department of Chemistry University of Illinois Urbana Illinois 61801 USA
| | - Scott E. Denmark
- Roger Adams Laboratory Department of Chemistry University of Illinois Urbana Illinois 61801 USA
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5
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Matviitsuk A, Panger JL, Denmark SE. Catalytic, Enantioselective Sulfenofunctionalization of Alkenes: Development and Recent Advances. Angew Chem Int Ed Engl 2020; 59:19796-19819. [PMID: 32452077 PMCID: PMC7936392 DOI: 10.1002/anie.202005920] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Indexed: 12/13/2022]
Abstract
The last decade has witnessed a burgeoning of new methods for the enantioselective vicinal difunctionalization of alkenes initiated by electrophilic sulfenyl group transfer. The addition of sulfenium ions to alkenes results in the generation of chiral, non-racemic thiiranium ions. These highly reactive intermediates are susceptible to attack by a myriad of nucleophiles in a stereospecific ring-opening event to afford anti 1,2-sulfenofunctionalized products. The practical application of sulfenium ion transfer has been enabled by advances in the field of Lewis base catalysis. This Review will chronicle the initial discovery and characterization of thiiranium ion intermediates followed by the determination of their configurational stability and the challenges of developing enantioselective variants. Once the framework for the reactivity and stability of thiiranium ions has been established, a critical analysis of pioneering studies will be presented. Finally, a comprehensive discussion of modern synthetic applications will be categorized around the type of nucleophile employed for sulfenofunctionalization.
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Affiliation(s)
- Anastassia Matviitsuk
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois, 61801, USA
| | - Jesse L Panger
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois, 61801, USA
| | - Scott E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois, 61801, USA
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6
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Ewing WC, Dellermann T, Angel Wong YT, Mattock JD, Vargas A, Bryce DL, Dewhurst RD, Braunschweig H. π-Complexes of Diborynes with Main Group Atoms. Chem Asian J 2020; 15:1553-1557. [PMID: 32207211 PMCID: PMC7317709 DOI: 10.1002/asia.202000185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/19/2020] [Indexed: 12/02/2022]
Abstract
We present herein an in-depth study of complexes in which a molecule containing a boron-boron triple bond is bound to tellurate cations. The analysis allows the description of these salts as true π complexes between the B-B triple bond and the tellurium center. These complexes thus extend the well-known Dewar-Chatt-Duncanson model of bonding to compounds made up solely of p block elements. Structural, spectroscopic and computational evidence is offered to argue that a set of recently reported heterocycles consisting of phenyltellurium cations complexed to diborynes bear all the hallmarks of π-complexes in the π-complex/metallacycle continuum envisioned by Joseph Chatt. Described as such, these compounds are unique in representing the extreme of a metal-free continuum with conventional unsaturated three-membered rings (cyclopropenes, azirenes, borirenes) occupying the opposite end.
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Affiliation(s)
- William C. Ewing
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Theresa Dellermann
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Y. T. Angel Wong
- Department of Chemistry and Biomolecular SciencesUniversity of OttawaOttawaOntarioK1N 6N5Canada
| | - James D. Mattock
- Department of ChemistrySchool of Life SciencesUniversity of SussexBrightonBN1 9QJSussexUK
| | - Alfredo Vargas
- Department of ChemistrySchool of Life SciencesUniversity of SussexBrightonBN1 9QJSussexUK
| | - David L. Bryce
- Department of Chemistry and Biomolecular SciencesUniversity of OttawaOttawaOntarioK1N 6N5Canada
| | - Rian D. Dewhurst
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Holger Braunschweig
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
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7
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Aragoni MC, Arca M, Blake AJ, Cadoni E, Copolovici LO, Isaia F, Lippolis V, Murgia S, Pop AM, Silvestru C, Tidey JP, Varga RA. Reaction of imidazoline-2-selone derivatives with mesityltellurenyl iodide: a unique example of a 3c-4e Se→Te←Se three-body system embedding a tellurenyl cation. NEW J CHEM 2019. [DOI: 10.1039/c9nj01593k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
1,2-Bis(3-methyl-4-imidazolin-2-selone)ethane was used to stabilize the first example of an authentic mesityltellurenyl cation, [MesTe]+, as a charge transfer adduct featuring a 3c-4e Se→Te←Se three-body system.
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Affiliation(s)
- M. Carla Aragoni
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- 09042 Monserrato (Cagliari)
- Italy
| | - Massimiliano Arca
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- 09042 Monserrato (Cagliari)
- Italy
| | | | - Enzo Cadoni
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- 09042 Monserrato (Cagliari)
- Italy
| | - Lucian O. Copolovici
- Faculty of Food Engineering
- Tourism and Environmental Protection, and Institute of Technical and Natural Sciences Research-Development-Innovation
- “Aurel Vlaicu” University
- Arad
- Romania
| | - Francesco Isaia
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- 09042 Monserrato (Cagliari)
- Italy
| | - Vito Lippolis
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- 09042 Monserrato (Cagliari)
- Italy
| | - Sergio Murgia
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Cagliari
- 09042 Monserrato (Cagliari)
- Italy
| | - Alexandra M. Pop
- Department of Chemistry
- Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC)
- Faculty of Chemistry and Chemical Engineering
- Babeş-Bolyai University
- 400028 Cluj-Napoca
| | - Cristian Silvestru
- Department of Chemistry
- Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC)
- Faculty of Chemistry and Chemical Engineering
- Babeş-Bolyai University
- 400028 Cluj-Napoca
| | | | - Richard A. Varga
- Department of Chemistry
- Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC)
- Faculty of Chemistry and Chemical Engineering
- Babeş-Bolyai University
- 400028 Cluj-Napoca
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8
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Poleschner H, Seppelt K. Seleniranium and Telluriranium Salts. Chemistry 2018; 24:17155-17161. [DOI: 10.1002/chem.201804307] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Indexed: 11/12/2022]
Affiliation(s)
- Helmut Poleschner
- Institut für Chemie und BiochemieAnorganische ChemieFreie Universität Berlin Fabeckstrasse 34–36 14195 Berlin Germany
| | - Konrad Seppelt
- Institut für Chemie und BiochemieAnorganische ChemieFreie Universität Berlin Fabeckstrasse 34–36 14195 Berlin Germany
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9
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Malischewski M, Seppelt K. Isolation and Characterization of a Non-Rigid Hexamethylbenzene-SO 2+ Complex. Angew Chem Int Ed Engl 2017; 56:16495-16497. [PMID: 29084371 DOI: 10.1002/anie.201708552] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Revised: 10/11/2017] [Indexed: 11/06/2022]
Abstract
During our studies towards the preparation of the pentagonal-pyramidal hexamethylbenzene dication C6 (CH3 )62+ , we isolated the unprecedented dicationic species C6 (CH3 )6 SO2+ (AsF6- )2 from the reaction of hexamethylbenzene with a mixture of anhydrous HF, AsF5 , and liquid SO2 . This compound can be understood as a complex of unknown SO2+ with hexamethylbenzene. Herein, we report on its synthesis, molecular structure, and spectroscopic characterization.
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Affiliation(s)
- Moritz Malischewski
- Freie Universität Berlin, Institut für Chemie und Biochemie-Anorganische Chemie, Fabeckstraße 34-36, 14195, Berlin, Germany.,Université Pierre et Marie Curie Paris 6, Institut Parisien de Chimie Moléculaire, 4 Place Jussieu, 75252, Paris cedex 5, France
| | - Konrad Seppelt
- Freie Universität Berlin, Institut für Chemie und Biochemie-Anorganische Chemie, Fabeckstraße 34-36, 14195, Berlin, Germany
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10
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Malischewski M, Seppelt K. Isolierung und Charakterisierung eines nicht-starren Hexamethylbenzol-SO2+
-Komplexes. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201708552] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Moritz Malischewski
- Freie Universität Berlin; Institut für Chemie und Biochemie - Anorganische Chemie; Fabeckstraße 34-36 14195 Berlin Deutschland
- Université Pierre et Marie Curie Paris 6; Institut Parisien de Chimie Moléculaire; 4 Place Jussieu 75252 Paris cedex 5 Frankreich
| | - Konrad Seppelt
- Freie Universität Berlin; Institut für Chemie und Biochemie - Anorganische Chemie; Fabeckstraße 34-36 14195 Berlin Deutschland
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11
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Ascheberg C, Bock J, Buß F, Mück-Lichtenfeld C, Daniliuc CG, Bergander K, Dielmann F, Hennecke U. Stable Bromiranium Ions with Weakly-Coordinating Counterions as Efficient Electrophilic Brominating Agents. Chemistry 2017. [DOI: 10.1002/chem.201701643] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Christoph Ascheberg
- Organisch-Chemisches Institut; Westfälische Wilhelms-Universität; Corrensstr. 40 48149 Münster Germany
| | - Jonathan Bock
- Organisch-Chemisches Institut; Westfälische Wilhelms-Universität; Corrensstr. 40 48149 Münster Germany
| | - Florenz Buß
- Institut für Anorganische Chemie; Westfälische Wilhelms-Universität; Corrensstr. 28/30 48149 Münster Germany
| | | | - Constantin G. Daniliuc
- Organisch-Chemisches Institut; Westfälische Wilhelms-Universität; Corrensstr. 40 48149 Münster Germany
| | - Klaus Bergander
- Organisch-Chemisches Institut; Westfälische Wilhelms-Universität; Corrensstr. 40 48149 Münster Germany
| | - Fabian Dielmann
- Institut für Anorganische Chemie; Westfälische Wilhelms-Universität; Corrensstr. 28/30 48149 Münster Germany
| | - Ulrich Hennecke
- Organisch-Chemisches Institut; Westfälische Wilhelms-Universität; Corrensstr. 40 48149 Münster Germany
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12
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Ryu T, Eom D, Shin S, Son JY, Lee PH. Synthesis of Multisubstituted Allenes, Furans, and Pyrroles via Tandem Palladium-Catalyzed Substitution and Cycloisomerization. Org Lett 2017; 19:452-455. [PMID: 28093911 DOI: 10.1021/acs.orglett.6b03561] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A palladium-catalyzed propargyl substitution reaction of propargyl acetates with indium organothiolates is developed for the synthesis of multisubstituted allenyl sulfides. This procedure can be applied to the synthesis of multisubstituted furans and pyrroles via tandem palladium-catalyzed propargyl substitution and cycloisomerization reaction in one pot.
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Affiliation(s)
- Taekyu Ryu
- Department of Chemistry, Kangwon National University , Chuncheon 24341, Republic of Korea
| | - Dahan Eom
- Department of Chemistry, Kangwon National University , Chuncheon 24341, Republic of Korea
| | - Seohyun Shin
- Department of Chemistry, Kangwon National University , Chuncheon 24341, Republic of Korea
| | - Jeong-Yu Son
- Department of Chemistry, Kangwon National University , Chuncheon 24341, Republic of Korea
| | - Phil Ho Lee
- Department of Chemistry, Kangwon National University , Chuncheon 24341, Republic of Korea
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13
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Liu LL, Zhu D, Cao LL, Stephan DW. N-Heterocyclic carbene stabilized parent sulfenyl, selenenyl, and tellurenyl cations (XH+, X = S, Se, Te). Dalton Trans 2017; 46:3095-3099. [DOI: 10.1039/c7dt00186j] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
NHC-stabilized parent sulfenyl (H–S+), selenenyl (H–Se+) and tellurenyl (H–Te+) cations have been achieved by treatment of NHC chalcogen adducts with trifluoromethanesulfonic acid.
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Affiliation(s)
- Liu Leo Liu
- Department of Chemistry
- University of Toronto
- Toronto
- Canada M5S 3H6
| | - Diya Zhu
- Department of Chemistry
- University of Toronto
- Toronto
- Canada M5S 3H6
| | - Levy L. Cao
- Department of Chemistry
- University of Toronto
- Toronto
- Canada M5S 3H6
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14
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Engesser TA, Lichtenthaler MR, Schleep M, Krossing I. Reactive p-block cations stabilized by weakly coordinating anions. Chem Soc Rev 2016; 45:789-899. [PMID: 26612538 PMCID: PMC4758321 DOI: 10.1039/c5cs00672d] [Citation(s) in RCA: 208] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Indexed: 12/12/2022]
Abstract
The chemistry of the p-block elements is a huge playground for fundamental and applied work. With their bonding from electron deficient to hypercoordinate and formally hypervalent, the p-block elements represent an area to find terra incognita. Often, the formation of cations that contain p-block elements as central ingredient is desired, for example to make a compound more Lewis acidic for an application or simply to prove an idea. This review has collected the reactive p-block cations (rPBC) with a comprehensive focus on those that have been published since the year 2000, but including the milestones and key citations of earlier work. We include an overview on the weakly coordinating anions (WCAs) used to stabilize the rPBC and give an overview to WCA selection, ionization strategies for rPBC-formation and finally list the rPBC ordered in their respective group from 13 to 18. However, typical, often more organic ion classes that constitute for example ionic liquids (imidazolium, ammonium, etc.) were omitted, as were those that do not fulfill the - naturally subjective -"reactive"-criterion of the rPBC. As a rule, we only included rPBC with crystal structure and only rarely refer to important cations published without crystal structure. This collection is intended for those who are simply interested what has been done or what is possible, as well as those who seek advice on preparative issues, up to people having a certain application in mind, where the knowledge on the existence of a rPBC that might play a role as an intermediate or active center may be useful.
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Affiliation(s)
- Tobias A. Engesser
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF) , Universität Freiburg , Albertstr. 21 , 79104 Freiburg , Germany .
| | - Martin R. Lichtenthaler
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF) , Universität Freiburg , Albertstr. 21 , 79104 Freiburg , Germany .
| | - Mario Schleep
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF) , Universität Freiburg , Albertstr. 21 , 79104 Freiburg , Germany .
| | - Ingo Krossing
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF) , Universität Freiburg , Albertstr. 21 , 79104 Freiburg , Germany .
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15
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Wang X, Gensch T, Glorius F. Highly selective synthesis of 6-substituted benzothiophenes by Sc(OTf)3-catalyzed intermolecular cyclization and sulfur migration. Org Chem Front 2016. [DOI: 10.1039/c6qo00477f] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A series of 6-substituted benzo[b]thiophenes was synthesized using a Sc(OTf)3-catalyzed intermolecular cyclization between para-substituted N-(arylthio)succinimides and alkynes taking advantage of a unique and selective 1,2-sulfur migration occuring via an electrophilic ipso cyclization to a key spirocyclic thiete intermediate.
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Affiliation(s)
- Xiaoming Wang
- Westfälische Wilhelms- Universität Münster
- Organisch-Chemisches Institut
- 48149 Münster
- Germany
| | - Tobias Gensch
- Westfälische Wilhelms- Universität Münster
- Organisch-Chemisches Institut
- 48149 Münster
- Germany
| | - Frank Glorius
- Westfälische Wilhelms- Universität Münster
- Organisch-Chemisches Institut
- 48149 Münster
- Germany
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Denmark SE, Rossi S, Webster MP, Wang H. Catalytic, enantioselective sulfenylation of ketone-derived enoxysilanes. J Am Chem Soc 2014; 136:13016-28. [PMID: 25192220 PMCID: PMC4183607 DOI: 10.1021/ja506133z] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Indexed: 01/07/2023]
Abstract
A catalytic, enantioselective, Lewis base-catalyzed α-sulfenylation of silyl enol ethers has been developed. To avoid acidic hydrolysis of the silyl enol ether substrates, a sulfenylating agent that did not require additional Brønsted acid activation, namely N-phenylthiosaccharin, was developed. Three classes of Lewis bases-tertiary amines, sulfides, and selenophosphoramides-were identified as active catalysts for the α-sulfenylation reaction. Among a wide variety of chiral Lewis bases in all three classes, only chiral selenophosphoramides afforded α-phenylthio ketones in generally high yield and with good enantioselectivity. The selectivity of the reaction does not depend on the size of the silyl group but is highly sensitive to the double bond geometry and the bulk of the substituents on the double bond. The most selective substrates are those containing a geminal bulky substituent on the enoxysilane. Computational analysis revealed that the enantioselectivity arises from an intriguing interplay among sterically guided approach, distortion energy, and orbital interactions.
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Affiliation(s)
- Scott E. Denmark
- Roger Adams Laboratory, Department
of Chemistry, University of Illinois, Urbana, Illinois 61801, United States
| | | | | | - Hao Wang
- Roger Adams Laboratory, Department
of Chemistry, University of Illinois, Urbana, Illinois 61801, United States
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XeF2/Fluoride Acceptors as Versatile One-Electron Oxidants. Angew Chem Int Ed Engl 2013; 52:12838-42. [DOI: 10.1002/anie.201307161] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Indexed: 11/07/2022]
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Poleschner H, Seppelt K. XeF2/Fluoridakzeptoren als vielseitige Einelektronen-Oxidationsmittel. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201307161] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Denmark SE, Kornfilt DJP, Vogler T. Catalytic asymmetric thiofunctionalization of unactivated alkenes. J Am Chem Soc 2011; 133:15308-11. [PMID: 21859086 DOI: 10.1021/ja2064395] [Citation(s) in RCA: 152] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Catalytic asymmetric sulfenylation of double bonds has been achieved using a BINAM-based phosphoramide catalyst and an electrophilic sulfur source. Simple alkenes as well as styrenes afforded sulfenylated tetrahydrofurans and tetrahydropyrans by closure with pendant hydroxyl or carboxyl groups. Intermolecular thiofunctionalizations were also achieved with simple alcohols or carboxylic acids as the nucleophiles.
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Affiliation(s)
- Scott E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, United States.
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20
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Denmark SE, Kalyani D, Collins WR. Preparative and mechanistic studies toward the rational development of catalytic, enantioselective selenoetherification reactions. J Am Chem Soc 2010; 132:15752-65. [PMID: 20961070 PMCID: PMC2981442 DOI: 10.1021/ja106837b] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A systematic investigation into the Lewis base catalyzed, asymmetric, intramolecular selenoetherification of olefins is described. A critical challenge for the development of this process was the identification and suppression of racemization pathways available to arylseleniranium ion intermediates. This report details a thorough study of the influences of the steric and electronic modulation of the arylselenenyl group on the configurational stability of enantioenriched seleniranium ions. These studies show that the 2-nitrophenyl group attached to the selenium atom significantly attenuates the racemization of seleniranium ions. A variety of achiral Lewis bases catalyze the intramolecular selenoetherification of alkenes using N-(2-nitrophenylselenenyl)succinimide as the electrophile along with a Brønsted acid. Preliminary mechanistic studies suggest the intermediacy of ionic Lewis base-selenium(II) adducts. Most importantly, a broad survey of chiral Lewis bases revealed that 1,1'-binaphthalene-2,2'-diamine (BINAM)-derived thiophosphoramides catalyze the cyclization of unsaturated alcohols in the presence of N-(2-nitrophenylselenenyl)succinimide and methanesulfonic acid. A variety of cyclic seleno ethers were produced in good chemical yields and in moderate to good enantioselectivities, which constitutes the first catalytic, enantioselective selenofunctionalization of unactivated olefins.
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Affiliation(s)
- Scott E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, United States.
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Denmark S, Vogler T. Synthesis and Reactivity of Enantiomerically Enriched Thiiranium Ions. Chemistry 2009; 15:11737-45. [DOI: 10.1002/chem.200901377] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Destro R, Ortoleva E, Soave R, Loconte L, Lo Presti L. Detection and kinetics of the single-crystal to single-crystal complete transformation of a thiiranium ion into thietanium ion. Phys Chem Chem Phys 2009; 11:7181-8. [PMID: 19672527 DOI: 10.1039/b901928f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The conversion of a di-tert-butyl-methylthiiranium ion into thietanium ion, that is reported in the literature as taking place spontaneously at 25 degrees C in a CD(2)Cl(2) solution, has been discovered to occur quantitatively at room temperature (RT) also in the crystalline state. The ring enlargement reaction is accompanied, in the solid phase, by a modest deterioration of the quality of the sample under investigation, and all three specimens here studied by in situ crystallography maintained their single-crystal nature up to 100% conversion. The rearrangement reaction implies the breaking of a C-S bond and the formation of a new bond of the same type, together with the migration of a methyl group. The extent of the corresponding atomic displacements has been measured by comparing the initial and final crystal structures. Several intermediate stages of the process have been investigated and characterized by the site occupancy factor of the episulfonium ion. The RT temporal evolution of this factor and that of the unit-cell volume indicate multi-step kinetics, with processes of simple molecular reorientation or displacement before and after the main, central stage, where the conversion reaction takes place. The overall kinetics is well described by an Avrami-Erofeev equation, with exponent m = 1.75(3) and rate coefficient k = 10.4(3) x 10(-8) s(-1) at 25 degrees C. Ab initio calculations in the gas phase predict a three-step mechanism resulting in a slightly spontaneous reaction with an overall decrease of entropy.
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Affiliation(s)
- Riccardo Destro
- Dipartimento di Chimica Fisica ed Elettrochimica, Università degli Studi di Milano, Milano, Italy.
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Denmark SE, Collins WR, Cullen MD. Observation of direct sulfenium and selenenium group transfer from thiiranium and seleniranium ions to alkenes. J Am Chem Soc 2009; 131:3490-2. [PMID: 19227982 DOI: 10.1021/ja900187y] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sulfenium and selenenium ions undergo a stereospecific transfer from the corresponding three-membered ring species ("-iranium ions") to unactivated alkenes with varying facility. The thiiranium and seleniranium hexafluoroantimonates could be generated by treatment of the corresponding chloro sulfides or selenides with silver hexafluoroantimonate, followed by removal of the silver chloride by filtration. Clean (1)H, (13)C, and (77)Se NMR spectra could be recorded for these species. Treatment of the S-phenylthiiranium ion with an alkene leads to a slow transfer of the sulfenium group at 0 degrees C. However, the S-methylthiiranium ion did not transfer the sulfenium group, even at room temperature. On the other hand, both the Se-phenyl- and Se-butylseleniranium ions transferred the selenenium moiety instantaneously at -70 degrees C. By measuring the equilibrium position for these transfers from both directions, the relative stability of the 1-phenylseleniranium ions could be established: cis-tetramethylene < trans-2,3-dipropyl approximately trans-2,3-diisopropyl < cis-hexamethylene.
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Affiliation(s)
- Scott E Denmark
- Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA.
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Borisov AV, Osmanov VK, Borisova GN, Matsulevich ZV, Fukin GK. Synthesis of condensed sulfur- and nitrogen-containing heterocycles via polar cycloaddition of hetarene sulfenyl chlorides to a C–C multiple bond. MENDELEEV COMMUNICATIONS 2009. [DOI: 10.1016/j.mencom.2009.01.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Perreault S, Poirier M, Léveillé P, René O, Joly P, Dory Y, Spino C. Mechanism and Regioselectivity of the Cycloaddition of Thiones Derived from Meldrum’s Acid, Malonates, or Other Dicarbonyls. J Org Chem 2008; 73:7457-66. [DOI: 10.1021/jo800945y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stéphane Perreault
- Département de Chimie, Université de Sherbrooke, 2500 Boul. Université, Sherbrooke, QC, Canada J1K 2R1
| | - Maude Poirier
- Département de Chimie, Université de Sherbrooke, 2500 Boul. Université, Sherbrooke, QC, Canada J1K 2R1
| | - Pascal Léveillé
- Département de Chimie, Université de Sherbrooke, 2500 Boul. Université, Sherbrooke, QC, Canada J1K 2R1
| | - Olivier René
- Département de Chimie, Université de Sherbrooke, 2500 Boul. Université, Sherbrooke, QC, Canada J1K 2R1
| | - Pascal Joly
- Département de Chimie, Université de Sherbrooke, 2500 Boul. Université, Sherbrooke, QC, Canada J1K 2R1
| | - Yves Dory
- Département de Chimie, Université de Sherbrooke, 2500 Boul. Université, Sherbrooke, QC, Canada J1K 2R1
| | - Claude Spino
- Département de Chimie, Université de Sherbrooke, 2500 Boul. Université, Sherbrooke, QC, Canada J1K 2R1
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Affiliation(s)
- Helmut Poleschner
- Institut für Chemie und Biochemie, Anorganische und Analytische Chemie, Freie Universität Berlin, Fabeckstrasse 34-36, 14195 Berlin, Germany.
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Dudnik AS, Sromek AW, Rubina M, Kim JT, Kel’in AV, Gevorgyan V. Metal-catalyzed 1,2-shift of diverse migrating groups in allenyl systems as a new paradigm toward densely functionalized heterocycles. J Am Chem Soc 2008; 130:1440-52. [PMID: 18173272 PMCID: PMC3686647 DOI: 10.1021/ja0773507] [Citation(s) in RCA: 256] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A general, mild, and efficient 1,2-migration/cycloisomerization methodology toward multisubstituted 3-thio-, seleno-, halo-, aryl-, and alkyl-furans and pyrroles, as well as fused heterocycles, valuable building blocks for synthetic chemistry, has been developed. Moreover, regiodivergent conditions have been identified for C-4 bromo- and thio-substituted allenones and alkynones for the assembly of regioisomeric 2-hetero substituted furans selectively. It was demonstrated that, depending on reaction conditions, ambident substrates can be selectively transformed into furan products, as well as undergo selective 6-exo-dig or Nazarov cyclizations. Our mechanistic investigations have revealed that the transformation proceeds via allenylcarbonyl or allenylimine intermediates followed by 1,2-group migration to the allenyl sp carbon during cycloisomerization. It was found that 1,2-migration of chalcogens and halogens predominantly proceeds via formation of irenium intermediates. Analogous intermediate can also be proposed for 1,2-aryl shift. Furthermore, it was shown that the cycloisomerization cascade can be catalyzed by Brønsted acids, albeit less efficiently, and commonly observed reactivity of Lewis acid catalysts cannot be attributed to the eventual formation of proton. Undoubtedly, thermally induced or Lewis acid-catalyzed transformations proceed via intramolecular Michael addition or activation of the enone moiety pathways, whereas certain carbophilic metals trigger carbenoid/oxonium type pathway. However, a facile cycloisomerization in the presence of cationic complexes, as well as observed migratory aptitude in the cycloisomerization of unsymmetrically disubstituted aryl- and alkylallenes, strongly supports electrophilic nature for this transformation. Full mechanistic details, as well as the scope of this transformation, are discussed.
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Affiliation(s)
- Alexander S. Dudnik
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, 4500 SES, M/C 111, Chicago, Illinois 60607-7061
| | - Anna W. Sromek
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, 4500 SES, M/C 111, Chicago, Illinois 60607-7061
| | - Marina Rubina
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, 4500 SES, M/C 111, Chicago, Illinois 60607-7061
| | - Joseph T. Kim
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, 4500 SES, M/C 111, Chicago, Illinois 60607-7061
| | - Alexander V. Kel’in
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, 4500 SES, M/C 111, Chicago, Illinois 60607-7061
| | - Vladimir Gevorgyan
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, 4500 SES, M/C 111, Chicago, Illinois 60607-7061
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Beaver MG, Billings SB, Woerpel KA. Nucleophilic Substitution Reactions of 2‐Phenylthio‐Substituted Carbohydrate Acetals and Related Systems: Episulfonium Ions vs. Oxocarbenium Ions as Reactive Intermediates. European J Org Chem 2008. [DOI: 10.1002/ejoc.200700911] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Matthew G. Beaver
- Department of Chemistry, University of California, Irvine, California 92697‐2025, USA, Fax: +1‐949‐824‐9920
| | - Susan B. Billings
- Department of Chemistry, University of California, Irvine, California 92697‐2025, USA, Fax: +1‐949‐824‐9920
| | - K. A. Woerpel
- Department of Chemistry, University of California, Irvine, California 92697‐2025, USA, Fax: +1‐949‐824‐9920
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Osmanov VK, Borisova GN, Geronikaki A, Borisova AV. Unusual intramolecular cyclization of adducts of diphenylacetylene with hetarenesulfenyl chlorides. Russ Chem Bull 2007. [DOI: 10.1007/s11172-007-0336-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Yin J, Cherney MM, Bergmann EM, Zhang J, Huitema C, Pettersson H, Eltis LD, Vederas JC, James MNG. An episulfide cation (thiiranium ring) trapped in the active site of HAV 3C proteinase inactivated by peptide-based ketone inhibitors. J Mol Biol 2006; 361:673-86. [PMID: 16860823 PMCID: PMC7172884 DOI: 10.1016/j.jmb.2006.06.047] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Revised: 06/19/2006] [Accepted: 06/20/2006] [Indexed: 11/17/2022]
Abstract
We have solved the crystal and molecular structures of hepatitis A viral (HAV) 3C proteinase, a cysteine peptidase having a chymotrypsin-like protein fold, in complex with each of three tetrapeptidyl-based methyl ketone inhibitors to resolutions beyond 1.4 A, the highest resolution to date for a 3C or a 3C-Like (e.g. SARS viral main proteinase) peptidase. The residues of the beta-hairpin motif (residues 138-158), an extension of two beta-strands of the C-terminal beta-barrel of HAV 3C are critical for the interactions between the enzyme and the tetrapeptide portion of these inhibitors that are analogous to the residues at the P4 to P1 positions in the natural substrates of picornaviral 3C proteinases. Unexpectedly, the Sgamma of Cys172 forms two covalent bonds with each inhibitor, yielding an unusual episulfide cation (thiiranium ring) stabilized by a nearby oxyanion. This result suggests a mechanism of inactivation of 3C peptidases by methyl ketone inhibitors that is distinct from that occurring in the structurally related serine proteinases or in the papain-like cysteine peptidases. It also provides insight into the mechanisms underlying both the inactivation of HAV 3C by these inhibitors and on the proteolysis of natural substrates by this viral cysteine peptidase.
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Key Words
- hav, hepatitis a virus
- fmdv, foot-and-mouth disease virus
- tgev, transmissible gastroenteritis coronavirus
- sars, severe acute respiratory syndrome
- bbl, carboxylbenzyloxyl-l-serine-β-lactone
- cmk, chloromethylketone
- fmk, fluoromethylketone
- ac, acetyl
- qmm, n, n-dimethyl glutamine
- hepatitis a virus
- 3c proteinase
- inhibitor design
- methylketone
- episulfide
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Affiliation(s)
- Jiang Yin
- Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, AB, Canada T6G 2H7
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Adam W, Bosio SG, Fröhling B, Leusser D, Stalke D. Unusual sulfur chemistry in the thermal reaction of sultene and thiophene endoperoxide sulfur donors with cyclic alkynes: reversible formation of a persistent thiirenium ion and trapping of a thiirene by [4 + 2] cycloaddition. J Am Chem Soc 2002; 124:8316-20. [PMID: 12105912 DOI: 10.1021/ja025934x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The highly reactive cyclooctyne 2b serves as sulfur acceptor for both sulfur donors, namely the sultene 1A and thiophene endoperoxide 1B to afford sulfur-transfer products. With the acid-activated sultene 1A, the persistent thiirenium ion 3Ab is formed, which has allowed the direct observation of the initial sulfur-transfer adduct. On treatment with base, the thiirenium ion 3Ab reverts quantitatively to the cyclooctyne and sultene, whereas in neutral media it rearranges to the diene 6Ab. The rearrangement to the diene 6Ab, as well as the formation of spirocyclic adduct 6Ac in the reaction with dithiocyclononyne 2c, is proposed to proceed through a carbene mechanism. In the reaction of the cyclooctyne 2b with thiophene endoperoxide 1B, a thiirene is formed through sulfur transfer by an intermediary oxathiirane derived from the thiophene endoperoxide; as final product, the episulfide (R*,R*,R*)-3Bb is produced diastereoselectively by immediate [4 + 2] cycloaddition of the thiirene with the heterodiene 4B.
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Affiliation(s)
- Waldemar Adam
- Institut für Organische Chemie, Am Hubland, Würzburg, Germany.
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Nucleophilic Vinylic Substitution and Vinyl Cation Intermediates in the Reactions of Vinyl Iodonium Salts. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2002. [DOI: 10.1016/s0065-3160(02)37001-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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