Scope of the Thermal Ring-Expansion Reaction of Boroles with Organoazides
Scope of the Thermal Ring-Expansion Reaction of Boroles with Organoazides
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DOI：
10.1002/chem.201700749
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发表时间：
2017-06-12
影响因子：
4.3
通讯作者：
Ruppert, Annika
中科院分区：
文献类型：
--
作者：
Braunschweig, Holger;Celik, Mehmet Ali;Ruppert, Annika
研究了硼杂环戊二烯与有机叠氮化物的热扩环反应中的电子和空间因素，该反应提供了获得高度芳基化的1，2-氮杂硼杂环戊二烯，苯的BN类似物的途径。各种硼杂环戊烯和有机叠氮化物的反应表明，该合成方法在提供1，2-氮杂硼杂环戊烯方面是相当普遍的，但各自的反应速率显示出对两种反应物上的取代基的强烈依赖性。通过UV/维斯、电化学、NMR和X射线衍射等方法对产物进行了表征，阐明了它们的结构，并强调了取代基对1，2-氮杂硼杂环的电子结构的影响。此外，分析了几种可能的机制途径为1，2-氮杂硼烷形成，通过DFT研究，揭示了一个两步机制，涉及叠氮硼加合物的形成和氮烯插入是有利的。
Electronic and steric factors have been investigated in the thermal ring expansion of boroles with organic azides, a reaction that provides access to highly arylated 1,2-azaborinines, BN analogues of benzene. Reactions of a variety of boroles and organic azides demonstrate that the synthetic method is quite general in furnishing 1,2-azaborinines, but the respective reaction rates reveal a strong dependence on the substituents on the two reactants. The products have been characterized by UV/Vis, electrochemical, NMR, and Xray diffraction methods, clarifying their constitutions and highlighting substituent effects on the electronic structure of the 1,2-azaborinines. Furthermore, analysis of several possible mechanistic pathways for 1,2-azaborinine formation, as studied by DFT, revealed that a two-step mechanism involving azide-borole adduct formation and nitrene insertion is favored.