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  1. Article ; Online: Chiral 4-MeO-Pyridine (MOPY) Catalyst for Enantioselective Cyclopropanation: Attenuation of Lewis Basicity Leads to Improved Catalytic Efficiency.

    Kluga, Rihards / Kinens, Artis / Suna, Edgars

    Chemistry (Weinheim an der Bergstrasse, Germany)

    2024  Volume 30, Issue 10, Page(s) e202301136

    Abstract: The design of pyridine-derived organocatalysts aims at the increase of their Lewis basicity, however such an approach is not always efficient. For example, strongly Lewis basic DMAP is completely inefficient as catalyst in the cyclopropanation reaction. ... ...

    Abstract The design of pyridine-derived organocatalysts aims at the increase of their Lewis basicity, however such an approach is not always efficient. For example, strongly Lewis basic DMAP is completely inefficient as catalyst in the cyclopropanation reaction. Herein we disclose an alternative approach that relies on attenuation of DMAP Lewis basicity. Specifically, the replacement of 4-dimethylamino substituent in DMAP for 4-MeO group delivered a highly efficient catalyst for cyclopropanation of electron-deficient olefins with α-bromoketones. Kinetic studies provide compelling evidence that the superior catalytic efficiency of 4-MeO pyridine (MOPY) is to be attributed to the favorable balance between Lewis basicity and leaving group ability. The use of chiral, enantiomerically pure MOPY catalyst has helped to achieve high enantioselectivities (up to 91 : 9 er) in the previously unreported pyridine-catalyzed cyclopropanation reaction.
    Language English
    Publishing date 2024-01-03
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 1478547-X
    ISSN 1521-3765 ; 0947-6539
    ISSN (online) 1521-3765
    ISSN 0947-6539
    DOI 10.1002/chem.202301136
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  2. Article ; Online: The emission efficiency of cationic solid state luminophores is directly proportional to the intermolecular charge transfer intensity.

    Leduskrasts, Kaspars / Kinens, Artis / Suna, Edgars

    Chemical communications (Cambridge, England)

    2023  Volume 59, Issue 45, Page(s) 6905–6908

    Abstract: Cationic luminophores have recently emerged as a class of efficient emitters in both the solid state and solutions. However, the underlying processes that secure the emission in these luminophores are poorly understood. Here, we employ charge transfer ... ...

    Abstract Cationic luminophores have recently emerged as a class of efficient emitters in both the solid state and solutions. However, the underlying processes that secure the emission in these luminophores are poorly understood. Here, we employ charge transfer integral (CTI) analysis in combination with X-ray single crystal data to uncover the emission mechanism in a series of pyridinium luminophores. We demonstrate that the solid state photoluminescence quantum yield (
    Language English
    Publishing date 2023-06-01
    Publishing country England
    Document type Journal Article
    ZDB-ID 1472881-3
    ISSN 1364-548X ; 1359-7345 ; 0009-241X
    ISSN (online) 1364-548X
    ISSN 1359-7345 ; 0009-241X
    DOI 10.1039/d3cc01674a
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Synthetic Access to Fluorocyclopropylidenes.

    Melngaile, Renate / Videja, Melita / Kuka, Janis / Kinens, Artis / Zacs, Dzintars / Veliks, Janis

    Organic letters

    2023  Volume 25, Issue 13, Page(s) 2280–2284

    Abstract: Herein we report an approach for the straightforward preparation of fluorocyclopropylidene group from aldehydes and ketones via Julia-Kocienski olefination using the newly developed reagent 5-((2-fluorocyclopropyl)sulfonyl)-1-phenyl- ... ...

    Abstract Herein we report an approach for the straightforward preparation of fluorocyclopropylidene group from aldehydes and ketones via Julia-Kocienski olefination using the newly developed reagent 5-((2-fluorocyclopropyl)sulfonyl)-1-phenyl-1
    Language English
    Publishing date 2023-03-30
    Publishing country United States
    Document type Journal Article
    ISSN 1523-7052
    ISSN (online) 1523-7052
    DOI 10.1021/acs.orglett.3c00579
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  4. Article: Metal-free glycosylation with glycosyl fluorides in liquid SO

    Gulbe, Krista / Lugiņina, Jevgeņija / Jansons, Edijs / Kinens, Artis / Turks, Māris

    Beilstein journal of organic chemistry

    2021  Volume 17, Page(s) 964–976

    Abstract: ... Liquid ... ...

    Abstract Liquid SO
    Language English
    Publishing date 2021-04-29
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 2192461-2
    ISSN 1860-5397
    ISSN 1860-5397
    DOI 10.3762/bjoc.17.78
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  5. Article: Cation–π interactions secure aggregation induced emission of planar organic luminophores

    Leduskrasts, Kaspars / Kinens, Artis / Suna, Edgars

    Chemical communications. 2019 Oct. 17, v. 55, no. 84

    2019  

    Abstract: The use of non-covalent intermolecular π+–π interactions between quaternary pyridinium or imidazolium cations and aromatic π systems is an efficient approach to achieve AIE in planar purely organic luminophores. ...

    Abstract The use of non-covalent intermolecular π+–π interactions between quaternary pyridinium or imidazolium cations and aromatic π systems is an efficient approach to achieve AIE in planar purely organic luminophores.
    Keywords cations ; chemical reactions ; imidazoles
    Language English
    Dates of publication 2019-1017
    Size p. 12663-12666.
    Publishing place The Royal Society of Chemistry
    Document type Article
    ZDB-ID 1472881-3
    ISSN 1364-548X ; 1359-7345 ; 0009-241X
    ISSN (online) 1364-548X
    ISSN 1359-7345 ; 0009-241X
    DOI 10.1039/c9cc06829e
    Database NAL-Catalogue (AGRICOLA)

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  6. Article: Acylative Dynamic Kinetic Resolution of Secondary Alcohols: Tandem Catalysis by HyperBTM and Bäckvall’s Ruthenium Complex

    Kinens, Artis / Balkaitis, Simonas / Ahmad, Omar K. / Piotrowski, David W. / Suna, Edgars

    Journal of organic chemistry. 2021 May 11, v. 86, no. 10

    2021  

    Abstract: Non-enzymatic dynamic kinetic resolution (DKR) of secondary alcohols by enantioselective acylation using an isothiourea-derived HyperBTM catalyst and racemization of slowly reacting alcohol by Bäckvall’s ruthenium complex is reported. The DKR approach ... ...

    Abstract Non-enzymatic dynamic kinetic resolution (DKR) of secondary alcohols by enantioselective acylation using an isothiourea-derived HyperBTM catalyst and racemization of slowly reacting alcohol by Bäckvall’s ruthenium complex is reported. The DKR approach features high enantioselectivities (up to 99:1), employs easy-to-handle crystalline 4-nitrophenyl isobutyrate as the acylating reagent, and proceeds at room temperature and under an ambient atmosphere. The stereoinduction model featuring cation−π system interactions between the acylated HyperBTM catalyst and π electrons of an alcohol aryl subunit has been elaborated by DFT calculations.
    Keywords acylation ; alcohols ; ambient temperature ; catalysts ; catalytic activity ; enantioselectivity ; organic chemistry ; ruthenium
    Language English
    Dates of publication 2021-0511
    Size p. 7189-7202.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 123490-0
    ISSN 1520-6904 ; 0022-3263
    ISSN (online) 1520-6904
    ISSN 0022-3263
    DOI 10.1021/acs.joc.1c00545
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  7. Article ; Online: Cation-π interactions secure aggregation induced emission of planar organic luminophores.

    Leduskrasts, Kaspars / Kinens, Artis / Suna, Edgars

    Chemical communications (Cambridge, England)

    2019  Volume 55, Issue 84, Page(s) 12663–12666

    Abstract: The use of non-covalent intermolecular π+-π interactions between quaternary pyridinium or imidazolium cations and aromatic π systems is an efficient approach to achieve AIE in planar purely organic luminophores. ...

    Abstract The use of non-covalent intermolecular π+-π interactions between quaternary pyridinium or imidazolium cations and aromatic π systems is an efficient approach to achieve AIE in planar purely organic luminophores.
    Language English
    Publishing date 2019-10-04
    Publishing country England
    Document type Journal Article
    ZDB-ID 1472881-3
    ISSN 1364-548X ; 1359-7345 ; 0009-241X
    ISSN (online) 1364-548X
    ISSN 1359-7345 ; 0009-241X
    DOI 10.1039/c9cc06829e
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Acylative Dynamic Kinetic Resolution of Secondary Alcohols: Tandem Catalysis by HyperBTM and Bäckvall's Ruthenium Complex.

    Kinens, Artis / Balkaitis, Simonas / Ahmad, Omar K / Piotrowski, David W / Suna, Edgars

    The Journal of organic chemistry

    2021  Volume 86, Issue 10, Page(s) 7189–7202

    Abstract: Non-enzymatic dynamic kinetic resolution (DKR) of secondary alcohols by enantioselective acylation using an isothiourea-derived HyperBTM catalyst and racemization of slowly reacting alcohol by Bäckvall's ruthenium complex is reported. The DKR approach ... ...

    Abstract Non-enzymatic dynamic kinetic resolution (DKR) of secondary alcohols by enantioselective acylation using an isothiourea-derived HyperBTM catalyst and racemization of slowly reacting alcohol by Bäckvall's ruthenium complex is reported. The DKR approach features high enantioselectivities (up to 99:1), employs easy-to-handle crystalline 4-nitrophenyl isobutyrate as the acylating reagent, and proceeds at room temperature and under an ambient atmosphere. The stereoinduction model featuring cation-π system interactions between the acylated HyperBTM catalyst and π electrons of an alcohol aryl subunit has been elaborated by DFT calculations.
    MeSH term(s) Alcohols ; Catalysis ; Kinetics ; Ruthenium ; Stereoisomerism
    Chemical Substances Alcohols ; Ruthenium (7UI0TKC3U5)
    Language English
    Publishing date 2021-05-11
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 123490-0
    ISSN 1520-6904 ; 0022-3263
    ISSN (online) 1520-6904
    ISSN 0022-3263
    DOI 10.1021/acs.joc.1c00545
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    In stock of ZB MED Cologne/Königswinter

    Zs.A 4473: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (2.OG)
    ab Jg. 2022: Lesesaal (EG)

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  9. Article: Preparative-Scale Synthesis of Vedejs Chiral DMAP Catalysts

    Kinens, Artis / Simonas Balkaitis / Edgars Suna

    Journal of organic chemistry. 2018 Sept. 26, v. 83, no. 20

    2018  

    Abstract: A scalable synthesis of chiral Vedejs-type DMAP catalysts is reported. The key step of the synthesis is amination of the enantiomerically pure 4-chloropyridine derivative using well-defined ZnCl₂(amine)₂ complexes. A series of Zn(II)–amine complexes have ...

    Abstract A scalable synthesis of chiral Vedejs-type DMAP catalysts is reported. The key step of the synthesis is amination of the enantiomerically pure 4-chloropyridine derivative using well-defined ZnCl₂(amine)₂ complexes. A series of Zn(II)–amine complexes have been synthesized to explore the scope of the ZnCl₂-mediated amination of 4-halopyridines. Mechanistic studies support a Zn(II)-facilitated nucleophilic aromatic substitution as a plausible mechanism for the chlorine-to-amine exchange.
    Keywords Lewis bases ; amination ; catalysts ; chemical structure ; organic chemistry ; organic compounds ; zinc
    Language English
    Dates of publication 2018-0926
    Size p. 12449-12459.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 123490-0
    ISSN 1520-6904 ; 0022-3263
    ISSN (online) 1520-6904
    ISSN 0022-3263
    DOI 10.1021/acs.joc.8b01687
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  10. Article ; Online: Preparative-Scale Synthesis of Vedejs Chiral DMAP Catalysts.

    Kinens, Artis / Balkaitis, Simonas / Suna, Edgars

    The Journal of organic chemistry

    2018  Volume 83, Issue 20, Page(s) 12449–12459

    Abstract: A scalable synthesis of chiral Vedejs-type DMAP catalysts is reported. The key step of the synthesis is amination of the enantiomerically pure 4-chloropyridine derivative using well-defined ... ...

    Abstract A scalable synthesis of chiral Vedejs-type DMAP catalysts is reported. The key step of the synthesis is amination of the enantiomerically pure 4-chloropyridine derivative using well-defined ZnCl
    Language English
    Publishing date 2018-10-10
    Publishing country United States
    Document type Journal Article
    ZDB-ID 123490-0
    ISSN 1520-6904 ; 0022-3263
    ISSN (online) 1520-6904
    ISSN 0022-3263
    DOI 10.1021/acs.joc.8b01687
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 4473: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (2.OG)
    ab Jg. 2022: Lesesaal (EG)

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