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  1. Article ; Online: Highly enantioselective synthesis of norcaradiene derivatives from naphthyl diazoacetamides using a Ru(II)-Pheox complex.

    Otog, Nansalmaa / Gantogos, Bilguun / Fujisawa, Ikuhide / Iwasa, Seiji

    Chemical communications (Cambridge, England)

    2022  Volume 58, Issue 88, Page(s) 12325–12328

    Abstract: The highly regio- and enantioselective intramolecular cyclopropanation reactions of naphthyl diazoacetamides have been reported herein. In the presence of a Ru(II)-Pheox catalyst, chiral and stable norcaradiene derivatives were obtained from the ... ...

    Abstract The highly regio- and enantioselective intramolecular cyclopropanation reactions of naphthyl diazoacetamides have been reported herein. In the presence of a Ru(II)-Pheox catalyst, chiral and stable norcaradiene derivatives were obtained from the corresponding diazoacetamides
    MeSH term(s) Ruthenium ; Stereoisomerism ; Diazonium Compounds
    Chemical Substances Ruthenium (7UI0TKC3U5) ; diazoacetamide (38118-67-1) ; bicyclo(4.1.0)hepta-2,4-diene ; Diazonium Compounds
    Language English
    Publishing date 2022-11-03
    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/d2cc04355f
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Synthesis of γ-lactams via Ru(II)–Pheox-catalyzed regioselective intramolecular Csp3–H insertion of diazoacetamides

    Fujii, Takuji / Thu, Huong Dang Thi / Iwasa, Seiji

    Tetrahedron letters. 2020 Sept. 10, v. 61, no. 37

    2020  

    Abstract: Herein, γ-lactam derivatives are obtained in high yield via highly regioselective intramolecular Csp³–H insertion reactions of α-diazoacetamides catalyzed by a rac-Ru(II)–Pheox complex. The catalytic system is applicable to a wide range of ... ...

    Abstract Herein, γ-lactam derivatives are obtained in high yield via highly regioselective intramolecular Csp³–H insertion reactions of α-diazoacetamides catalyzed by a rac-Ru(II)–Pheox complex. The catalytic system is applicable to a wide range of diazoacetamides under mild conditions to produce the corresponding γ-lactams.
    Keywords catalytic activity ; chemical reactions ; regioselectivity
    Language English
    Dates of publication 2020-0910
    Publishing place Elsevier Ltd
    Document type Article
    Note NALT-AP-4-rerunAP2-fuzzy
    ZDB-ID 204287-3
    ISSN 1873-3581 ; 0040-4039
    ISSN (online) 1873-3581
    ISSN 0040-4039
    DOI 10.1016/j.tetlet.2020.152276
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    In stock of ZB MED Cologne/Königswinter

    Zs.A 2837: Show issues Location:
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  3. Article ; Online: Amine-Catalyzed Decarboxylative Aldol Reaction of β-Ketocarboxylic Acids with Trifluoropyruvates.

    Kawanishi, Ryouta / Hattori, Shinya / Iwasa, Seiji / Shibatomi, Kazutaka

    Molecules (Basel, Switzerland)

    2019  Volume 24, Issue 15

    Abstract: Decarboxylative aldol reaction of aliphatic carboxylic acids is a useful method for C-C bond formation because carboxylic acids are an easily available class of compounds. In this study, we found that the decarboxylative aldol reaction of tertiary β- ... ...

    Abstract Decarboxylative aldol reaction of aliphatic carboxylic acids is a useful method for C-C bond formation because carboxylic acids are an easily available class of compounds. In this study, we found that the decarboxylative aldol reaction of tertiary β-ketocarboxylic acids and trifluoropyruvates proceeded smoothly to yield the corresponding aldol products in high yields and with high diastereoselectivity in the presence of a tertiary amine catalyst. In this reaction, we efficiently constructed a quaternary carbon center and an adjacent trifluoromethylated carbon center. This protocol was also extended to an enantioselective reaction with a chiral amine catalyst, and the desired product was obtained with up to 73% enantioselectivity.
    MeSH term(s) Aldehydes/chemistry ; Amines/chemistry ; Carboxylic Acids/chemistry ; Catalysis ; Cinchona Alkaloids/chemistry ; Fluorides/chemistry ; Molecular Structure ; Pyruvic Acid/analogs & derivatives ; Stereoisomerism
    Chemical Substances Aldehydes ; Amines ; Carboxylic Acids ; Cinchona Alkaloids ; Pyruvic Acid (8558G7RUTR) ; 3-hydroxybutanal (8C6G962B53) ; Fluorides (Q80VPU408O)
    Language English
    Publishing date 2019-07-30
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 1413402-0
    ISSN 1420-3049 ; 1431-5165 ; 1420-3049
    ISSN (online) 1420-3049
    ISSN 1431-5165 ; 1420-3049
    DOI 10.3390/molecules24152773
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    Zs.MO 81: Show issues

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  4. Article ; Online: Decarboxylative Fluorination of 2-Pyridylacetates.

    Kawanishi, Ryouta / Phongphane, Lacksany / Iwasa, Seiji / Shibatomi, Kazutaka

    Chemistry (Weinheim an der Bergstrasse, Germany)

    2019  Volume 25, Issue 31, Page(s) 7453–7456

    Abstract: Syntheses of substituted pyridines and fluorinated compounds, which are often pharmaceutical targets, are important objectives in organic chemistry. Herein, we found that decarboxylative fluorination of lithium 2-pyridylacetates occur under catalyst-free ...

    Abstract Syntheses of substituted pyridines and fluorinated compounds, which are often pharmaceutical targets, are important objectives in organic chemistry. Herein, we found that decarboxylative fluorination of lithium 2-pyridylacetates occur under catalyst-free conditions. The phenomenon can be applied to one-pot transformation of substituted methyl 2-pyridylacetate to 2-(fluoroalkyl)pyridine by decarboxylative fluorination of the intermediate lithium 2-pyridylacetate. This method was also applied to the syntheses of 2-(difluoroalkyl)pyridines.
    Language English
    Publishing date 2019-04-26
    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.201900565
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  5. Article ; Online: Synthesis of Forms of a Chiral Ruthenium Complex Containing a Ru-C

    Inoue, Hayato / Phan Thi Thanh, Nga / Fujisawa, Ikuhide / Iwasa, Seiji

    Organic letters

    2020  Volume 22, Issue 4, Page(s) 1475–1479

    Abstract: Organometallic complexes [Ru- ... ...

    Abstract Organometallic complexes [Ru-C
    Language English
    Publishing date 2020-01-28
    Publishing country United States
    Document type Journal Article
    ISSN 1523-7052
    ISSN (online) 1523-7052
    DOI 10.1021/acs.orglett.0c00050
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  6. Article ; Online: Enantioselective Cyclopropanation of a Wide Variety of Olefins Catalyzed by Ru(II)-Pheox Complexes.

    Chanthamath, Soda / Iwasa, Seiji

    Accounts of chemical research

    2016  Volume 49, Issue 10, Page(s) 2080–2090

    Abstract: The transition-metal-catalyzed asymmetric cyclopropanation of olefins with diazoacetates has become one of the most important methods for the synthesis of optically active cyclopropane derivatives, which are key pharmaceutical building blocks and present ...

    Abstract The transition-metal-catalyzed asymmetric cyclopropanation of olefins with diazoacetates has become one of the most important methods for the synthesis of optically active cyclopropane derivatives, which are key pharmaceutical building blocks and present in a large number of natural products. To date, significant progress has been made in this area of research, and efficient stereocontrolled synthetic approaches to cyclopropane derivatives have been developed using rhodium, ruthenium, copper, and cobalt catalysts. However, the vast majority of these strategies are limited to electron-rich olefins, such as styrene derivatives, due to the electrophilicity of the metal-carbene intermediates generated from the reaction of the metal with the diazo compound. Recently, the D
    Language English
    Publishing date 2016--18
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1483291-4
    ISSN 1520-4898 ; 0001-4842
    ISSN (online) 1520-4898
    ISSN 0001-4842
    DOI 10.1021/acs.accounts.6b00070
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  7. Article: Synthesis of Forms of a Chiral Ruthenium Complex Containing a Ru–Colefin(sp2) Bond and Their Application to Catalytic Asymmetric Cyclopropanation Reactions

    Inoue, Hayato / Fujisawa, Ikuhide / Iwasa, Seiji / Phan Thi Thanh, Nga

    Organic letters. 2020 Jan. 28, v. 22, no. 4

    2020  

    Abstract: Organometallic complexes [Ru–Colefin(sp2)–Ru(II)–Pheox 2a–2d] containing a Ru–Colefin(sp2) bond have been prepared from unsaturated chiral oxazoline derivatives and evaluated for asymmetric cyclopropanation reactions. The corresponding optically active ... ...

    Abstract Organometallic complexes [Ru–Colefin(sp2)–Ru(II)–Pheox 2a–2d] containing a Ru–Colefin(sp2) bond have been prepared from unsaturated chiral oxazoline derivatives and evaluated for asymmetric cyclopropanation reactions. The corresponding optically active cyclopropanes were obtained with high yields and high stereoselectivities (≥99/<1 trans/cis, 99% trans ee). The enantioselectivities were found to be affected by the geminal substituent on the Ru–C(sp2) bond. In particular, Ru(II)–Prox catalyst 2c, in which there was no geminal substituent on the metal, was shown to have the highest enantioselectivities.
    Keywords catalysts ; catalytic activity ; chemical reactions ; chemical structure ; enantioselectivity ; organometallic compounds ; ruthenium
    Language English
    Dates of publication 2020-0128
    Size p. 1475-1479.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1523-7052
    DOI 10.1021/acs.orglett.0c00050
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  8. Article ; Online: Regio- and Enantioselective Intramolecular Amide Carbene Insertion into Primary C-H Bonds Using Ru(II)-Pheox Catalyst.

    Nakagawa, Yoko / Chanthamath, Soda / Liang, Yumeng / Shibatomi, Kazutaka / Iwasa, Seiji

    The Journal of organic chemistry

    2019  Volume 84, Issue 5, Page(s) 2607–2618

    Abstract: We have established a method for the highly regio- and enantioselective functionalization of tert-butyl groups via intramolecular amide carbene insertion into C-H bonds, yielding γ-lactams with 91% ee in up to 99% yield. This reaction uses a ruthenium(II) ...

    Abstract We have established a method for the highly regio- and enantioselective functionalization of tert-butyl groups via intramolecular amide carbene insertion into C-H bonds, yielding γ-lactams with 91% ee in up to 99% yield. This reaction uses a ruthenium(II) phenyl oxazoline (Ru(II)-Pheox) complex. The catalytic intramolecular carbene transfer reaction to the primary C-H bond proceeds rapidly and selectively compared to that with secondary C-H, benzylic secondary C-H, tert-C-H, or sp
    Language English
    Publishing date 2019-02-12
    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.8b03044
    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
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  9. Article ; Online: Catalytic Asymmetric Carbene Transfer Reactions of Diazo Oxime Ethers with Olefins and Their Synthetic Applications.

    Da Ho, Linh / Otog, Nansalmaa / Fujisawa, Ikuhide / Iwasa, Seiji

    Organic letters

    2019  Volume 21, Issue 18, Page(s) 7470–7474

    Abstract: The first catalytic asymmetric cyclopropanation of diazo oxime ethers with olefins was developed. In the presence of a Ru(II)-Pheox catalyst, various optically active cyclopropyl oxime derivatives were obtained in high yields (up to 99%) with high ... ...

    Abstract The first catalytic asymmetric cyclopropanation of diazo oxime ethers with olefins was developed. In the presence of a Ru(II)-Pheox catalyst, various optically active cyclopropyl oxime derivatives were obtained in high yields (up to 99%) with high enantioselectivities (up to 98% ee). Furthermore, optically active cyclopropyl oxime ethers could be successfully converted into the corresponding cyclopropyl methylamine derivatives via metal hydride and Grignard reagent mediated Beckmann rearrangement, which are potential candidates for the assessment of biological and pharmaceutical activities.
    Language English
    Publishing date 2019-09-04
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 1523-7052
    ISSN (online) 1523-7052
    DOI 10.1021/acs.orglett.9b02771
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: Asymmetric Synthesis of α-Chloro-α-halo Ketones by Decarboxylative Chlorination of α-Halo-β-ketocarboxylic Acids

    Kitahara, Kazumasa / Mizutani, Haruna / Iwasa, Seiji / Shibatomi, Kazutaka

    Synthesis

    2019  Volume 51, Issue 23, Page(s) 4385–4392

    Abstract: Chiral α-chloro-α-fluoro ketones were synthesized by enantio­selective decarboxylative chlorination of α-chloro-β-ketocarboxylic acids in the presence of a chiral amine catalyst. The reaction yielded the corresponding α-chloro-α-fluoro ketones with ... ...

    Abstract Chiral α-chloro-α-fluoro ketones were synthesized by enantio­selective decarboxylative chlorination of α-chloro-β-ketocarboxylic acids in the presence of a chiral amine catalyst. The reaction yielded the corresponding α-chloro-α-fluoro ketones with moderate-to-high enantioselectivity (up to 90% ee). The method was also applied to the synthesis of α-bromo-α-chloro ketones with 90% ee.
    Keywords decarboxylative chlorination ; chiral amine catalyst ; enantio­selective synthesis ; β-ketocarboxylic acids ; fluorinated compounds
    Language English
    Publishing date 2019-07-23
    Publisher © Georg Thieme Verlag
    Publishing place Stuttgart ; New York
    Document type Article
    ZDB-ID 2033062-5
    ISSN 1437-210X ; 0039-7881
    ISSN (online) 1437-210X
    ISSN 0039-7881
    DOI 10.1055/s-0039-1690009
    Database Thieme publisher's database

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