[4 + 2] Cycloaddition of thiophene S-monoxides to activated methylenecyclopropanes
作者:Thies Thiemann、Daisuke Ohira、Yuanqiang Li、Tsuyoshi Sawada、Shuntaro Mataka、Karsten Rauch、Mathias Noltemeyer、Armin de Meijere
DOI:10.1039/b003850o
日期:——
determined as being endo,syn. The Wittig olefination of cyclopropanone hemiacetal to generate the methylenecyclopropanes and the subsequent cycloaddition can be carried out in a one-pot operation. This procedure is one of many potential one-pot or multi-component reactions involving stabilized phosphoranes. A further example of this type of reaction is shown in the novel desilylation–Wittig olefination
噻吩小号-oxides 4已经显示出经历[4 + 2]环加成与亚甲基环2与一个或两个电子受体取代基,即甚至在四取代的2-氯-2- cyclopropylideneacetate 2C反应很好。但是,对于四取代的烯烃双(亚环丙基)2f,必须施加高压使其与4反应。在所有反应中仅形成一种非对映异构体。的两个cycloadducts,X射线晶体结构分析图3a和3f中,已经执行,它们的相对配置确定为内切,顺。环丙烷半缩醛的Wittig烯烃化反应生成亚甲基环丙烷,随后的环加成反应可以一锅操作进行。该过程是涉及稳定的膦烷的许多潜在的一锅法或多组分反应之一。这种新型反应的另一个例子是新型的甲硅烷基化-1-乙氧基-1-三甲基甲硅烷基氧基环丙烷5的Wittig烯化反应,一步一步产生环亚丙基乙酸酯,例如2a。