Intramolecular Carbolithiation Reactions in the Construction of Medium-Sized Rings. Synthesis of Pyrroloisoquinolines, Benzazepines, and Benzazocines
作者:Oihane García-Calvo、Estíbaliz Coya、Sergio Lage、Iain Coldham、Nuria Sotomayor、Esther Lete
DOI:10.1002/ejoc.201200994
日期:2013.3
Subsequent intramolecular carbolithiation of the 2-alkenyl-substituted ortho-lithiated N-benzylpyrroles proceeded efficiently when the alkene was substituted with an electron-withdrawing group. The procedure is applicable to the construction of six-, seven-, and eight-membered rings, thus, opening new routes to pyrroloisoquinolines, benzazepines, and benzazocines. Although the use of (–)-sparteine
在通过碘-锂交换形成芳基锂中间体方面,均三甲基锂(MesLi)被发现优于丁基锂。当烯烃被吸电子基团取代时,2-烯基取代的邻位锂化N-苄基吡咯的后续分子内碳锂化反应有效进行。该程序适用于六元、七元和八元环的构建,从而开辟了吡咯并异喹啉、苯并氮杂和苯并佐辛的新路线。尽管使用 (-)-sparteine 作为手性配体导致低水平的对映选择,但可以通过将此方案应用于衍生自脯氨酸的相关吡咯烷来合成对映异构纯异喹啉,因为反应以完全非对映选择性进行。