Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
Institute for Sustainable Chemistry & Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
Chemistry. 2023 May 11;29(27):e202300210. doi: 10.1002/chem.202300210. Epub 2023 Mar 27.
Direct insertion of unsaturated substrates into a five-membered borole ring is a useful method to obtain valuable heterocycles containing one or more three-coordinate boron atoms. A highly Lewis acidic 9-o-carboranyl-9-borafluorene, in which the o-carboranyl substituent is connected via one of the cluster carbon atoms to the boron atom of the 9-borafluorene unit, was found to react with a vast array of unsaturated molecules, such as alkynes, aldehydes and various organic azides, to form larger boraheterocyclic products. The ring expansion reactions of the central borole ring proceed rapidly at room temperature, cementing the role of the o-carboranyl substituent in enhancing the insertion reactivity of 9-borafluorenes.
直接将不饱和底物插入到五元硼杂环中是一种获得含有一个或多个三配位硼原子的有价值杂环的有用方法。一种高路易斯酸性的 9-邻-碳硼烷-9-硼芴，其中邻-碳硼烷取代基通过簇碳原子之一连接到 9-硼芴单元的硼原子上，被发现可以与各种不饱和分子反应，如炔烃、醛和各种有机叠氮化物，形成更大的硼杂环产物。中环硼杂环的环扩张反应在室温下迅速进行，这巩固了邻-碳硼烷取代基在增强 9-硼芴插入反应性方面的作用。
