On the Question of Cyclopropylidene Intermediates in Cyclopropene-to-Allene Rearrangements − Tetrakis(trimethylsilyl)cyclopropene, 3-Alkenyl-1,2,3-tris(trimethylsilyl)cyclopropenes, and Related Model Compounds
作者:Armin de Meijere、Dietmar Faber、Ute Heinecke、Robin Walsh、Thomas Müller、Yitzhak Apeloig
DOI:10.1002/1099-0690(200102)2001:4<663::aid-ejoc663>3.0.co;2-e
日期:2001.2
surfaces for the potential pyrolysis pathways. Although the potential cyclopropylidene species in these rearrangements are significantly stabilized, for none of the systems was this sufficient to permit isomerization via these intermediates. 36b is calculated to rearrange via a vinylidene intermediate to give 3-methyl-1-trimethylsilyl-1-butyne (47), in agreement with experiment. Comparison of the calculations
已经制备了几种四取代的环丙烯并研究了它们的热解和光解。四(三甲基甲硅烷基)环丙烯(10)以 25% 的产率从三(三甲基甲硅烷基)环丙烯鎓六氯锑酸盐(9)获得,得到四(三甲基甲硅烷基)丙二烯(12)作为唯一的热和光化学产物。[D8] 甲苯中的动力学研究表明具有 Arrhenius 参数 log(A/s−1) = 11.75 ± 1.20 和 Ea = (37.5 ± 2.5) kcal mol−1 的一阶行为。所有三种新的 3-烯基-1,2,3-三(三甲基甲硅烷基)环丙烯(17a-c,分别以 C1-、C2- 和 C3-烯基作为系链)在辐照后得到丙二烯,但在热条件下只有两个( 17a、17c)得到丙二烯,而17b由于分子内烯反应产生双环[4.1.0]庚-3-烯衍生物22。带有 1,2-双(烯基二甲基甲硅烷基)取代基的另外两种环丙烯(33a,b)的光解也得到相应的丙二烯作为唯一产物。因为这些系链