• Title/Summary/Keyword: Regioselective synthesis

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Thirty Six Years of Research on the Selective Reduction and Hydroboration

  • Cha, Jin-Soon
    • Bulletin of the Korean Chemical Society
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    • v.32 no.6
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    • pp.1808-1846
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    • 2011

  • From 1975 to 2011, for thirty six years, the author and his collaborators have developed a variety of reducing and hydroborating agents, and applied them to organic synthesis, which involves the 1,2-reduction of ${\alpha}$,${\beta}$-unsaturated carbonyl compounds, stereoselective reduction of cycloalkanones, regioselective ring-opening of epoxides, partial reduction of carboxylic acid derivatives to aldehydes, regioselective addition to carbon-carbon multiple bonds, etc. by utilizing metal hydrides and the newly-devised the Meerwein-Ponndorf-Verley (MPV) type reagents. Such developments provide a new synthetic methodology making possible valuable selective reductions and hydroborations, not practical previously.

  • https://doi.org/10.5012/bkcs.2011.32.6.1808 인용 PDF KSCI

A facile synthesis of 4-cyano-3,5-difluorophenol (4-cyano-3,5-difluorophenol의 새로운 합성법)

  • Song, Jeong-Sup
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.6
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    • pp.1308-1312
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    • 2006

  • 4-Cyano-3,5-difluorophenol, useful as intermediate in the manufacturing of liquid crystals, was prepared by the regioselective iodination of 3,5-difluorophenol to give 4-iodo-3,5-difluorophenol, which was then converted to 4-cyano-3,5-difluorophenol under a mild reaction condition. The reaction products were characterized by spectroscopic methods and confirmed by comparison of these analytical data with reported values in the literatures.

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A First Synthesis of Isofagar-idine:Topoisomerase I Inhibitor

  • Cho, Won-Jea;Miyoji Hanaoka
    • Archives of Pharmacal Research
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    • v.19 no.3
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    • pp.240-242
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    • 1996

  • We have reported the convenient biomimetic methodology for the synthesis of all kinds of substituent pattern benzo[c]phenanthridine alkaloids (Hanaoka et al., 1990; Hanaoka et al., 1991). Regioselective demethylation of C-8 position on oxyfagaridine (5), an intermediate for the synthesis of Fagaridine (4), would afford the precursor for the synthesis of Isofagaridine because the strong hydrogen bonding between amide and hydroxyl group of C-7 position probably resists to be reacted with week base and electrophiles. Thus, a selective alkylation of dihydroxy compound supposed to be possible and be lead to the target compound, Isofagaridine.

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Concise Synthesis of (±)-Rhinacanthin A, Dehydro α-Lapachone, and β-Lapachone, and Pyranonaphthoquinone Derivatives

  • Wang, Xue;Chen, Ye;Lee, Yong-Rok
    • Bulletin of the Korean Chemical Society
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    • v.32 no.1
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    • pp.153-156
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    • 2011

  • A concise synthesis of (${\pm}$)-rhinacanthin A is achieved in two steps by epoxidation of dehydro-$\alpha$-lapachone, followed by chemo- and regioselective reduction. Dehydro-$\alpha$-lapachone was also synthesized in two steps starting from 4-methoxy-1-naphthol by ethylenediamine diaetate (EDDA)-catalyzed benzopyran formation and a CAN-mediated oxidation reaction. $\beta$-Lapachone was synthesized in three steps from 4-methoxy-1-naphthol by benzopyran formation, catalytic hydrogenation, and Jones oxidation. As additional reactions, synthesis of pyranonaphthoquinone derivatives with the pyranokunthone B skeleton has been achieved in a single step from readily available 2-hydroxy-6-methoxy-1,4-naphthoquinone and 2-hydroxy-7-methoxy-1,4-naphthoquinone.

  • https://doi.org/10.5012/bkcs.2011.32.1.153 인용 PDF KSCI

A Regioselectio Synthesis of ${\beta}-Lactones$; Bromolactonization of 2-Substituted-1-Cyclohexenyl-1-acetic acid

  • Jew, Snag-Sup;Lee, Hee-Soon;Koo, Bon-Am
    • Archives of Pharmacal Research
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    • v.17 no.5
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    • pp.327-330
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    • 1994

  • Bromolactonization of 2-substituted-1-cyclohexenyl-1-acetic acids with 1, 3-dibromo-5, 5-dime-thylhydantoin 9DBH) and potsssium tertiary butoxide (t-BuOK0 in anhydrous DMF was found to proceed in a highly regioselective manner. The reaction predominantly resulted in the formation of ${\betha}-lactones$ (greater than 96%).

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