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    Please use this identifier to cite or link to this item: http://asiair.asia.edu.tw/ir/handle/310904400/17236

    Title: Preparation and 13C NMR study on 1-aryl-3,3-difluoro-2-(phenylethynyl)-cyclopropenes: long distance Hammett substituent effect
    Authors: Shaw-Tao Lin;Chuan-Chen Lee;李傳珍;En-Chien Wu
    Contributors: 保健營養生技學系
    Keywords: Sonogashira reaction;Cyclopropene;Acetylene;13C NMR;SCS
    Date: 2008-05
    Issue Date: 2012-11-26 10:30:22 (UTC+8)
    Abstract: Coupling of 1-aryl-3,3-difluoro-2-chlorocyclopropenes and phenylacetylene using Sonogashira reaction with Pd(OAc)2 and CuI as the catalyst with K2CO3 as a base yields phenylethynylcyclopropenes in high selectivity and good yields. The 13C chemical shifts of Cɛ of ∼105 ppm on acetylene group significantly different from phenylacetylene (84 ppm) suggest that the acetylene group possesses less sp hybrid character due to an unusual long distance Hammett substituent effect. It is also confirmed by the substituent parameter analysis, while the Cβ and Cɛ display the strong resonance effect (their values are 6.89 and 3.37, respectively).
    Relation: TETRAHEDRON, 64(22):5103-5106.
    Appears in Collections:[食品營養與保健生技學系] 期刊論文

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