Nitrogen-Containing Tricyclic and Tetracyclic Compounds by Stereoselective Samarium Diiodide Promoted Cyclizations of Quinolyl-Substituted Ketones – A New Access to Azasteroids
作者:Francesca Aulenta、Ulrike K. Wefelscheid、Irene Brüdgam、Hans-Ulrich Reißig
DOI:10.1002/ejoc.200800019
日期:2008.5
withsamarium diiodide promoted cyclizations of quinolyl-substituted ketones 6–12 and also the attempted reductive cyclization of carbazole-containing ketone 13. These precursors were prepared by Heck-type coupling reactions of the corresponding hetaryl nonaflates with adequately substituted olefins as a key step. The cyclization of compounds 7–12 led to nitrogen-containing tri- and tetracyclic compounds 23–28
在本报告中,我们描述了我们的实验处理二碘化钐促进喹啉取代酮 6-12 的环化以及含咔唑酮 13 的还原环化尝试。这些前体是通过相应的杂芳基壬酸酯与充分取代的烯烃作为关键步骤。化合物 7-12 的环化导致含氮三环和四环化合物 23-28 的产率中等至良好,并且通常以高度非对映选择性的方式进行。氮杂四环具有类固醇骨架,但具有非自然的顺-顺环 B、C 和 D 环。我们还描述了这些产品的苯乙烯型双键的化学改性,这提供了高度官能化的类固醇型化合物,例如 29 、 30 和 32。