Preparation and 13C NMR study on 1-aryl-3,3-difluoro-2-(phenylethynyl)cyclopropenes: long distance Hammett substituent effect
作者:Shaw-Tao Lin、Chuan-Chen Lee、En-Chien Wu
DOI:10.1016/j.tet.2008.03.061
日期:2008.5
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
使用Sonogashira反应与Pd(OAc)2和CuI作为催化剂,以K 2 CO 3为碱,将1-芳基-3,3-二氟-2-氯环丙烯与苯乙炔偶联,可以高选择性和高收率得到苯乙炔基环丙烯。乙炔基团上C 5〜105 ppm的13 C化学位移显着不同于苯乙炔(84 ppm),这表明乙炔基团由于异常的长距离哈米特取代效应而具有较少的sp杂化特性。取代基参数分析也证实了这一点,而Cβ和Cɛ表现出强烈的共振效应(它们的值分别为6.89和3.37)。
Difluorocarbene chemistry: synthesis of gem-difluorocyclopropenylalkynes and 3,3,3′,3′-tetrafluorobicyclopropyl-1,1′-dienes
作者:Zhan-Ling Cheng、Qing-Yun Chen
DOI:10.1016/j.jfluchem.2004.10.003
日期:2005.1
by the Sonogashira reaction of 3,3-difluoro-1-iodocyclopropenes with terminal alkynes. Onto these new alkynes addition of difluorocarbene, generated from the decomposition of FSO2CF2COOTMS in diglme in the presence of 10 mol% anhydrous NaF at 120 °C, gives 3,3,3′,3′-tetrafluorobicyclopropyl-1,1′-dienes. Acid hydrolysis of gem-difluorocyclopropenylalkynes in refluxing CH3OH affords the corresponding