Álvarez-Fernández Ana, Suárez-Rodríguez Tatiana, Suárez-Sobrino Ángel L
Departamento de Química Orgánica e Inorgánica, Universidad de Oviedo , Julián Clavería 8, 33071 Oviedo, Spain.
J Org Chem. 2014 Jul 18;79(14):6419-23. doi: 10.1021/jo500378z. Epub 2014 Jun 25.
Two new selective cascade processes for enynyl Fischer carbene complexes 1 are described in their reaction with alkynyl malonates. When carbene complexes 1 react with the sodium enolate of homopropargyl malonates 3 a consecutive Michael-type addition/cyclopentannulation/6-exo cyclization takes place leading, in a regio- and stereoselective way, to n/5/6 angular tricyclic compounds 5. Furthermore, when propargylic malonates are used, a delayed protonation of the reaction mixture allows intermediate 1,4-addition adduct Ia to evolve through a 5-exo cyclization, consisting of an intramolecular nucleophilic attack from the central carbon of the allenylmetallate over the triple C-C bond. Further spontaneous cyclopentannulation of the resulting metallatriene gives rise to bicyclic and linear polycyclic compounds 6 and 7, some of them bearing a polyquinane framework.
本文描述了烯炔基费歇尔卡宾配合物1与炔丙基丙二酸酯反应的两种新型选择性串联反应过程。当卡宾配合物1与高炔丙基丙二酸酯3的烯醇钠反应时，会发生连续的迈克尔型加成/环戊环化/6-外向环化反应，以区域和立体选择性的方式生成n/5/6角型三环化合物5。此外，当使用炔丙基丙二酸酯时，反应混合物的延迟质子化使中间体1,4-加成加合物Ia通过5-外向环化反应进行转化，该反应由烯丙基金属酸盐的中心碳对碳-碳三键进行分子内亲核攻击组成。所得金属三烯的进一步自发环戊环化反应产生双环和线性多环化合物6和7，其中一些具有多喹烷骨架。
