• Title/Summary/Keyword: diastereoselectivity

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Stereocontrolled Preparation of 2,6-Disubstituted 4-Methylenetetrahydropyrans by Lewis Acid Promoted Allylsilane-Acetal Cyclization

  • 성태명;곽우영;강경태
    • Bulletin of the Korean Chemical Society
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    • v.19 no.8
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    • pp.862-868
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    • 1998

  • The Lewis acid mediated intramolecular additions of allylsilanes to acetal substrates are described. Excellent regio- and diastereoselectivity are achieved by boron trifluoride promoted cyclization of allysilane-acetals 5 and 8 derived from hydroxy allysilances 3. Cyclizations occur in moderate to high yields, providing directr routes to cis-2, 6-disubstituted 4-methylenetetrahydropyrans 6 and 9.

  • https://doi.org/10.5012/bkcs.1998.19.8.862 인용 PDF

Synthesis and Herbicidal Activity of New Hexahydrobenzisoxazole Derivatives (새로운 hexahydrobenzisoxazole derivatives 유도체의 합성 및 제초활성)

  • Kim, Hyoung-Rae;Park, Hyun-Ju;Kim, Hyung-Ki;Song, Jong-Hwan;Jeon, Dong-Ju;Kim, Kyung-Mahn;Kim, Tae-Joon;Ryu, Eung-K.
    • The Korean Journal of Pesticide Science
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    • v.3 no.3
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    • pp.68-70
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    • 1999

  • Hexahydro-1,2-bertzisoxazol-4-ols prepared from the diastereoselective reductions of 3-aryl-3a,4,5,6,7,7a-hexahydro-1,2-benzisoxazol-4-ones were reacted with benzyl chloride in the presence of sodium hydride to give new 4-benzyloxy-3a,4,5,6,7,7a-hexahydro-1,2-benzisoxazoles, which showed good herbicidal activity together with excellent selectivity on rice under submerged paddy conditions.

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Diastereoselective Reduction of 2,3-Dioxo-4-carboxy-5-substituted Pyrrolidines Using NaBH4/AcOH and Heterogenous Hydrogenation Reactions

  • Mohammat, Mohd Fazli;Mansor, Nurul Shulehaf;Shaameri, Zurina;Hamzah, Ahmad Sazali
    • Journal of the Korean Chemical Society
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    • v.59 no.1
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    • pp.31-35
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    • 2015

  • Diastereoselective reduction of 2,3-dioxo-4-carboxy-5-(substituted)pyrrolidine 1 by $NaBH_4/AcOH$ and heterogenous hydrogenation were reported. Stereochemical assignment and diastereomeric ratios of the products were determined using $^1H$ NMR and single crystal X-ray analyses. The steric factors of the C-5 substituents of the pyrrolidinone was shown to have an interesting influence on both the yield and diastereoselectivity of the reduced product.

  • https://doi.org/10.5012/jkcs.2015.59.1.31 인용 PDF KSCI KPUBS HTML

Diastereoselective Synthesis of Polysubstituted Pyrrolidinone as a Key Intermediate for the Anticancer Agents by Palladium(II)­Catalyzed Carboxylation

  • Choi Dong-Rack;Lee Kee-Young;Chung Yun-Sung;Joo Jae-Eun;Kim Yong-Hyun;Oh Chang-Young;Lee Yiu-Suk;Ham Won-Hun
    • Archives of Pharmacal Research
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    • v.28 no.2
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    • pp.151-158
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    • 2005

  • Palladium(II)-catalyzed carboxylation of chiral olefins 6a-d has been examined under various conditions. In the weak basic condition ($K_{2}CO_3$), 7a-d were obtained in good yields. Alternatively, in the strong basic condition, pyrrolidinones 8a-d were obtained resulting in excellent yields and with high diastereoselectivity.

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