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化学学报
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化学学报 ›› 1965, Vol. 31 ›› Issue (6): 451-457.    下一篇

硫醇对炔属化合物的加成反应 Ⅴ.苯硫酚对几种炔烃加成的立体化学

刘有成, 王序昆   

  1. 兰州大学化学系
  • 投稿日期:1963-10-04 修回日期:1965-06-03 发布日期:2013-06-03

STUDIES ON THE ADDITION OF THIOLS TO ACETYLENIC COMPOUNDS Ⅴ. THE STEREOCHEMISTRY OF THE ADDITION OF THIOPHENOL TO SOME ACETYLENES

LIU Yu-CHENG, WANG SUE-KWUNG   

  1. Department of Chemistry, Lanchow, University
  • Received:1963-10-04 Revised:1965-06-03 Published:2013-06-03

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苯硫酚与苯乙炔、对溴苯乙炔、对硝基苯乙炔及丙炔酸在室温进行直接加成时,生成相应的1:1加成物,其主体构型均属反式,分别为反-β-苯硫基苯乙烯(Ⅰa),反-β-苯硫基对溴苯乙烯(Ⅱa),反-β-苯硫基对硝基苯乙烯(Ⅲa)及反-β-苯硫基丙烯酸(Ⅳa)。加成物的得率按以下顺序而递減:Ⅰa>Ⅱa>Ⅲa>Ⅳa。在低温(-45～-35°)苯硫酚与四种炔烃在溶液中反应时,除对硝基苯乙炔不起反应外,其它三种炔化合物均给出全部或绝大部分顺式构型产物(反式加成),分别为顺-β-苯硫基苯乙烯(Ⅰb,100%),顺-β-苯硫基对溴苯乙烯(Ⅱb,75%)及顺-β-苯硫基丙烯酸(Ⅳb,80%)。所有顺式构型产物在反应条件下都稳定,只是在加热到160°以上时才转化为反式构型产物。苯硫酚对炔烃的直接加成为一自由基反应,所观察到的立体化学结果被解释为加成反应中形成的中间体自由基(Ⅴ),由于R(苯基或羧基)与处于顺式位置的C6H5S基的空间位阻,在与苯硫酚进行链转移之前发生异构化所致。因为Ⅴ的异构化为Ⅵ需要一定的活化能,故在低温下的加成全部或绝大部分按反式加成进行,在温度升高时全部转为顺式加成。苯硫酚与对硝基苯乙炔在无水乙醚中在—60°形成一深紫色溶液,两小时后颜色逐渐变淡,这似乎表明有自由基的形成。苯硫酚与四种炔化合物在乙氧基负离子催化下进行加成时,得到全部为反式加成的产物,分别为Ⅰb,Ⅱb,顺-β-苯硫基对硝基苯乙烯(Ⅲb)及Ⅳb。

When the direct addition of thiophenol to phenylacetylene, p-bromophenylacetylene,p-nitrophenylacetylene, and propiolic acid was conducted at room temperature, the corresponding 1:1 adducts of traps-configuration were obtained, which were trans-β-phenyl-thiostyrene (Ⅰa),trans-β-phenylthio-p-bromostyrene (Ⅱa),and trans-β-phenylthioacrylic acid (Ⅳa) respectively. The yields of these adducts decreased in the following order:Ⅰa>Ⅱa>Ⅲa>Ⅳa. When the addition of thiophenol to the four acetylenes was carried out in solution at low temperature(-45~-35°),except p-nitrophenylacetylene which did not react under these conditions, all the other three compounds gave adducts only or mostly of cis-configuration (traps addition),which were cis-β-phenylthiostyrene (Ⅰb, 100%) cis-phenylthio-p-bromostyrene(Ⅱb, 75%) and cis-phenylthioacrylic acid (Ⅳb, 80%). All these compounds of cis-configuration were stable under the reaction conditions, being transformed to trans-configuration only on heating to or above 160°.