Drescher Regina, Lin Shujuan, Hofmann Alexander, Lenczyk Carsten, Kachel Stephanie, Krummenacher Ivo, Lin Zhenyang, Braunschweig Holger
Institute for Inorganic Chemistry , Institute for Sustainable Chemistry & Catalysis with Boron , Julius-Maximilians-Universität Würzburg , Am Hubland , 97074 Würzburg , Germany . Email:
Department of Chemistry , The Hong Kong University of Science and Technology , Clear Water Bay , Kowloon , Hong Kong , China . Email:
Chem Sci. 2020 May 14;11(21):5559-5564. doi: 10.1039/d0sc02032j. eCollection 2020 Jun 7.
Aside from simple Lewis acid-base chemistry, the reaction chemistry of aluminacyclopentadienes, which are commonly referred to as aluminoles or simply alumoles, remains relatively underdeveloped. To date, few attempts to extend their inherent insertion and cycloaddition reactivity to the construction of stable aluminum-containing heterocycles have been reported. Herein, we demonstrate the selective ring expansion of a cyclopentadienyl-substituted alumole with a series of organic azides to form unsaturated six-membered AlN heterocycles. Depending on the substituent on the azide, the reaction proceeds either with or without loss of dinitrogen, leading to incorporation of only the "NR" unit of the azide or the entire azo substituent into the periphery of the heterocycle. A deeper understanding of these ring expansion reactions is reached through computational studies, illustrating deviations in the mechanism as a function of the organic azide employed.
除了简单的路易斯酸碱化学外，环戊二烯基铝（通常称为铝杂茂或简称为铝茂）的反应化学仍相对不发达。迄今为止，很少有将其固有的插入和环加成反应活性扩展到构建稳定的含铝杂环的尝试被报道。在此，我们展示了环戊二烯基取代的铝茂与一系列有机叠氮化物的选择性扩环反应，以形成不饱和六元AlN杂环。根据叠氮化物上的取代基，反应在有或没有氮气损失的情况下进行，导致仅将叠氮化物的“NR”单元或整个偶氮取代基并入杂环的外围。通过计算研究对这些扩环反应有了更深入的理解，阐明了反应机理随所使用有机叠氮化物的变化而产生的偏差。
