• Title/Summary/Keyword: Alkynes

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Thexylhaloborane-Methyl Sulfide as Hydroborating and Stereoselective Reducing Agent

  • Cha Jin Soon;Min Soo Jin;Kim, Jong Mi
    • Bulletin of the Korean Chemical Society
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    • v.15 no.6
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    • pp.478-483
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    • 1994

  • Reactions of alkenes and alkynes with thexylhaloborane-methyl sulfide (ThxBHX${\cdot}$SMe$_2$, X= Cl, Br, I) were investigated in detail in order to elucidate the effect of halogen substituent in thexylborane and hence establish their usefulness as hydroborating agent. The reagents readily hydroborated alkenes at $50^{circ}C$and alkynes at $25^{circ}C$ in exceptional regioselectivity. Especially, the selectivity achieved by the bromo and iodo derivative reaches essentially 100%. In addition to that, $ThxBHX{\cdot}SMe_2$ was applied to the reduction of cyclic ketones to examine its stereoselectivity. The halogen substituent in thexylborane plays an important role in the stereoselective reduction. The stereoselectivity increased dramatically with increasing steric size of the substituent. Finally, the iodo derivative achieved highly stereoselective reduction, such selectivity being comparable to that previously achieved with trialkylborohydrides.

  • https://doi.org/10.5012/bkcs.1994.15.6.478 인용 PDF

Synthesis, Reactions and Catalytic Activities of Water Soluble Rhodium and Iridium-Sulfonated Triphenylphosphine Complexes. 1. Polymerization of Terminal Alkynes

  • 주광석;김상열;진종식
    • Bulletin of the Korean Chemical Society
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    • v.18 no.12
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    • pp.1296-1301
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    • 1997

  • Polymerization of terminal alkynes (phenlacetylene and 4-ethynyltoluene) catalyzed by water soluble rhodium (Ⅰ) complex, RhCl(CO)(TPPTS)2 (TPPTS=m-P(C6H4SO3Na)3) (1) selectively produces cis-transoid polymers at room temperature in homogeneous solution of H2O and MeOH as well as in biphasic solutions of H2O and CHCl3. The rate of polymerization is higher in H2O/MeOH than in H2O/CHCl3. The iridium analog, IrCl(CO)(TPPTS)2 (2) shows catalytic activity for the polymerization of phenylacetylene only at elevated temperature to give trans-polymers. The polymerization rate increases significantly when the trimethylamine N-oxide (Me3NO) was added to the reaction mixtures. The electronic absorption spectra of the cis-transoid polymers show three absorption bands whereas the trasn-polymers show only one absorption band. It seems that the electronic absorption bands depend on the configuration of the polymers.

  • https://doi.org/10.5012/bkcs.1997.18.12.1296 인용 PDF

Efficient Oxidative Scission of Alkenes or Alkynes with Heterogeneous Ruthenium Zirconia Catalyst (루테늄 지르코니아 불균일 촉매를 이용한 알켄 또는 알킨의 효과적인 산화절단반응)

  • Irshad, Mobina;Choi, Bong Gill;Kang, Onyu;Hong, Seok Bok;Hwang, Sung Yeon;Heo, Young Min;Kim, Jung Won
    • Applied Chemistry for Engineering
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    • v.27 no.6
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    • pp.659-663
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    • 2016

  • The efficiency of a heterogeneous ruthenium zirconia catalyst ($Ru(OH)_x/ZrO_2$) was demonstrated to the selective oxidative transformation of alkenes or alkynes. The scissions of C-C double bonds to aldehydes and triple bonds to diketones or carboxylic acids were carried out with (diacetoxyiodo)benzene as an oxidant under dichloromethane (5 mL)/water (0.5 mL) solvent system at $30^{\circ}C$ for wide range of substrates. The $Ru(OH)_x/ZrO_2$composite showed higher catalytic activity and selectivity than other ruthenium-based homogeneous or heterogeneous catalysts for the scission reaction. The catalyst exhibited a high mechanical stability, and no leaching of the metal was observed during the reaction. These features ensured the reusability of the catalyst for several times for the oxidative cleavage of unsaturated hydrocarbons.

  • https://doi.org/10.14478/ace.2016.1106 인용 PDF KSCI