Regio- and Stereoselective Cyclization Reactions of Unsaturated Silyl Enol Ethers by Photoinduced Electron Transfer – Mechanistic Aspects and Synthetic Approach
作者:Sandra Hintz、Jochen Mattay、Rudi van Eldik、Wen-Fu Fu
DOI:10.1002/(sici)1099-0690(199808)1998:8<1583::aid-ejoc1583>3.0.co;2-r
日期:1998.8
various silyl enol ethers and silyloxy-2H-chromones bearing an olefinic or silylacetylenic side chain, The reactions result in regioselective ring closure with the formation of bi- to tetracyclic ring systems with a well-defined ring juncture, e.g. perhydrophenanthrenones 13 or benzo-annellated xanthenones 24. Our investigations have focussed on the optimization of this cyclization method with regard
氧化光诱导电子转移 (PET) 反应已经用各种带有烯属或甲硅烷基炔属侧链的甲硅烷基烯醇醚和甲硅烷氧基-2H-色酮进行,反应导致区域选择性闭环,形成具有孔的双环至四环系统-定义的环接点,例如全氢菲酮 13 或苯并退火的呫吨酮 24。我们的研究集中在该环化方法在辐照时间和产品产率方面的优化。使用共敏化 PET 方法可以减少辐照时间。在甲硅烷基上修饰底物可提高产率。此外,我们发现溶剂和压力依赖性是重要的工具,可以控制区域化学。实现了通过自由基阳离子反应途径合成 6-endo 产物,以及通过自由基中间体实现 5-exo 闭环。讨论了机械细节,包括氘标记实验的发现。