Cycloaddition of trifluoromethyl azafulvenium methides: synthesis of new trifluoromethylpyrrole-annulated derivatives
作者:Cláudio M. Nunes、Manuela Ramos Silva、Ana Matos Beja、Rui Fausto、Teresa M.V.D. Pinho e Melo
DOI:10.1016/j.tetlet.2009.11.033
日期:2010.1
azafulvenium methides acting as 1,3-dipoles is reported. These azafulvenium methides showed site selectivity in the reaction with strong electron-deficient dipolarophiles leading exclusively to 1,3-cycloadducts. In the cycloaddition with less-activated dipolarophiles 1,7-cycloadducts resulting from [8π+2π] cycloaddition are also formed. FMO analysis of the cycloaddition reactions allowed the rationalization
探索了三氟甲基氮杂富烯鎓甲基化物的化学方法,从而为三氟甲基吡咯环化系统提供了一条新途径。据报道,氮杂富硒鎓盐起着1,3-偶极子作用的第一个证据。这些与甲基氮杂富烯鎓的甲基化物在与强电子缺乏的偶极亲和剂的反应中显示出位点选择性,从而仅导致1,3-环加合物。在具有较少活化的双亲性的环加成反应中,还形成了由[8π+2π]环加成反应形成的1,7-环加合物。FMO对环加成反应的分析使所观察到的选择性合理化。