Cyclic Seven-Membered Ketene Imines from Hindered‘Thiocarbonyl Ylides’ and 2,3-Bis(trifluoromethyl)fumaronitrile: Properties and Surprising Reactions
作者:Rolf Huisgen、Elke Langhals、Kurt Polborn、Konstantin Karaghiosoff
DOI:10.1002/hlca.200490130
日期:2004.6
rationalized with the assumption of a nine-membered cyclic intermediate. In CD3CN at 80°, 13 and 12 (+11B) are stable and occur in a ratio of ca. 1 : 1. Hindered ‘thiocarbonyl ylides’ 2C and 2D produce, in reactions with (E)-3 or (Z)-3, the cyclic ketene imines 4C and 4D, respectively, which likewise isomerize to trans-thiolanes 6C and 6D. In contrast to 6B and 6C, the less-hindered thiolane 6D is thermostable
可从1,1,3,3-四甲基茚满硫酮和CH 2 N 2中获得“硫代羰基内酯” 2B,然后在40–50°下挤出N 2。将位阻2B与2,3-双(三氟甲基)富马腈((E)-3)进行原位环加成可高产率获得可分离的螺环烯酮亚胺4B。X射线分析揭示了角度变形,其中环应变是4B高反应性的原因。在40°的CDCl 3中,4B异构化为反式-螺硫杂环戊烷6B并以1∶1的比例在平行反应中形成1,2-双(三氟甲基)环丙烷-1,2-二甲腈(12)(+硫代酮11B)的片段。4:1。范德华应变限制了6B的热稳定性,在CDCl 3中60°时,其缓慢转化为11B和12。动力学研究符合两性离子中间体5B的纱布和反构象。在CD 3 CN中,4B进行第三次平行反应,这导致与CD 3形成正式加合物CN。X射线分析显示13 13。这种深层次的,出乎意料的结构变化是在假设九元循环中间体的情况下合理化的。在80°的CD 3 CN中,13和12(+