• Title/Summary/Keyword: Grignard Reaction

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Theoretical Study on the Regioselectivity of Tetrazolylimines with Alkyl Grignard Reagents

  • 유성은;공영대;김수경
    • Bulletin of the Korean Chemical Society
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    • v.20 no.4
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    • pp.441-444
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    • 1999
  • The alkyl Grignard addition reaction on 1-benzyltetrazolylimine proceeds to give N-alkylated products (azophilic addition) and, in contrast, the same reaction on 2-benzyltetrazolylimine produced predominantly C-alkylated products (carbophilic addition). In this report we described theoretical explanations for this experimental finding on the basis of the frontier molecular orbitals and the electrostatic nature of the reactants and the reaction intermediates.

The Syntheses of Organostannyl Compounds by Grignard Reaction Catalyzed by Ether in Non-ethereal Media (비에테르성 용매중에서 에테르촉매를 사용한 그리냐르반응에 의한 유기스탄닐화합물의 합성)

  • Bae Seok Seo;Il Kyu Lee
    • Journal of the Korean Chemical Society
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    • v.23 no.6
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    • pp.392-395
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    • 1979
  • Some alkyl or aryl halides, such as ethyl bromide, butyl chloride, phenyl bromide and benzyl chloride, were reacted by Grignard's method with anhydrous tin tetrachloride in hydrocarbon media. When small amounts of ether were added into the Grignard reaction step, the reaction proceeded rather smoothly and gave good yields of corresponding organotin compounds.

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Mechanistic Aspects in the Grignard Coupling Reaction of Bis(chloromethyl)dimethylsilane with Trimethylchlorosilane

  • 조연석;유복렬;안삼영;정일남
    • Bulletin of the Korean Chemical Society
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    • v.20 no.4
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    • pp.422-426
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    • 1999
  • The Grignard reactions of bis(chloromethyl)dimethylsilane (1) with trimethylchlorosilane (2) in THF give both the intermolecular C-Si coupling and intramolecular C-C coupling products. At beginning stage, 1 reacts with Mg to give the mono-Grignard reagent ClCH2Me2SiCH2MgCl (1) which undergoes the C-Si coupling reaction to give MC2Si(CH2SiMe3)2 3, or C-C coupling to a mixture of formula Me3SiCH2(SiMe2CH2CH2)nR1 (n = 1, 2, 3, ..; 4a, R1I = H: 4b, R1 = SiMe3). In the reaction, two reaction pathways are involved: a) Ⅰ reacts with 2 to give Me3SiCH2SiMe2CH2Cl 6 which further reacts with Mg to afford a Me2SiCH2Mel-SiCH2MgCl (Ⅱ) or b) I cyclizes intramolecularly to a silacyclopropane intermediate A, which undergoes a ring-opening polymerization by the nucleophilic attack of the intermediates I or Ⅱ, followed by the termination reaction with H2O and 2, to give 4a and 4b, respectively. As the mole ratio of 2/1 increased from 2 to 16 folds, the formation of product 3 increased from 16% to 47% while the formation of polymeric products 4 was reduced from 60% to 40%. The intermolecular C-Si coupling reaction of the pathway a becomes more favorable than the intramolecular C-C coupling reaction of the pathways b at the higher mole ratio of 2/1.

Grignard Coupling Reaction of Bis(chloromethyl)diorganosilanes with Dichloro(diorgano)silanes: Syntheses of 1,3-Disilacyclobutanes

  • 조연석;유복렬;안삼영;정일남
    • Bulletin of the Korean Chemical Society
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    • v.20 no.4
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    • pp.427-430
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    • 1999
  • The Grignard coupling reaction of bis(chloromethyl)diorganosilanes [(ClCH2)2SiR1R2: R1 = R2 = Me, la; R1 = Me, R2 = Ph, lb; R1 = R2 = Ph, lc] with diorganodichlorosilanes [(Cl2SiR3R4: R3 = R4 = Me, 2a; R3 = Me, R4 = Ph, 2b; R3 = R4 = Ph, 2c] at THE reflux temperature gave the intermolecular C-Si coupling product of 1,1,3,3-tetraorgano-1,3-disilacyclobutanes 3a-f in poor to moderate yields ranging from 7% to 50% along with polydiorganosilapropanes. The cyclization reaction of la-c with methyl-substituted dichlorosilanes 2a, b gave 1,3-disilacyclobutanes 3a-c, e, d in moderate yields (42-50%), while the same reaction with dichlorodiphenylsilane (2c) to 1,3-disilacyclobutanes 3d, f resulted in low yield (7-18%) probably due to the steric hindrance of two-phenyl groups on the silicon of 2c.

Nickel-Catalyzed Hydrogenolysis of Arenesulfonates Using Secondary Alkyl Grignard Reagents

  • Kim, Chul-Bae;Cho, Chul-Hee;Park, Kwang-Yong
    • Bulletin of the Korean Chemical Society
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    • v.28 no.2
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    • pp.281-284
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    • 2007
  • Neopentyl arenesulfonates react with secondary alkylmagnesium chlorides in the presence of dppfNiCl2 to produce the corresponding arenes via the reductive cleavage of carbon-sulfur bond. Highest yield is obtained by using three equivalents of Grignard reagent to a mixture of arenesulfonate and dppfNiCl2 in Et2O at room temperature. This reaction represents a novel method allowing the efficient hydrogenolysis of sulfur-containing groups in aromatic compounds.

Nickel-Catalyzed Coupling of Arenesulfonates with Primary Alkylmagnesium Halides

  • Cho, Chul-Hee;Sun, Myung-Chul;Park, Kwang-Yong
    • Bulletin of the Korean Chemical Society
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    • v.26 no.9
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    • pp.1410-1414
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    • 2005
  • Neopentyl arenesulfonates reacted with primary alkylmagnesium halides in the presence of $(PPh_3)_2NiCl_2$ to produce the corresponding alkylarenes. The efficiency of this coupling reaction considerably depends on the nature of catalyst and solvent. Highest yield was obtained by using three equivalents of Grignard reagent to a mixture of $(PPh_3)_2NiCl_2$ and arenesulfonate in refluxing $Et_2O$. This reaction represents a novel method allowing the efficient and creative substitution of sulfur-containing groups in aromatic compounds. It also shows that the alkyloxysulfonyl group might be a suitable alternative to halides and triflate in some circumstances.

The Synthesis of Chlorin-based Photosensitizers for using in Photodynamics Therapy by Modification of Methyl Pyropheophorbide-a

  • Wang, Jin-Jun;Han, Guang-Fan;Shim, Young-Key
    • Journal of Photoscience
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    • v.8 no.2
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    • pp.75-77
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    • 2001
  • The Grignard reaction of methyl pyropheophorbide-a (MPP-a) was performed to introduce lengthy alkyl chain for improving lipophilicity. After the introduction of alkyl chain to the both of carbonyls, peripheral aldehyde and cyclopentanone, the obtained diol 3 was subjected to dehydration to give monodehydrate product 4 selectively. The Qy band of prepared compounds were affected by the substituents on the Qy axis (N$\sub$21/-N$\sub$23/).

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