The aromatic Claisen rearrangement of a 1,2-azaborine
The aromatic Claisen rearrangement of a 1,2-azaborine
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1,2-氮杂硼烷的芳香族克莱森重排
DOI：
10.1039/d2ob02186b
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发表时间：
2023
影响因子：
3.2
通讯作者：
Liu, Shih-Yuan
中科院分区：
文献类型：
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作者：
Robichaud, Hannah M.;Ishibashi, Jacob S.;Ozaki, Tomoya;Lamine, Walid;Miqueu, Karinne;Liu, Shih-Yuan
第一芳香族克莱森重排的1，2-氮杂硼描述沿着与氮杂硼与其直接的全碳类似物的反应的定量动力学比较。在140-180 °C的所有温度下，氮杂硼杂环A以干净的区域选择性方式重排，并且比全碳底物B反应更快。活化自由能从观察到的一级速率常数（A：ΔG <$298K = 32.7 kcal mol−1; B：ΔG <$298K = 34.8 kcal mol−1）中提取，对应于在观察到的反应温度下A的速率快20倍。DFT计算表明，重排通过一个协调的六元过渡态进行，BN和CC环的电子结构是主要负责观察到的区域选择性和相对反应性。
The first aromatic Claisen rearrangement of a 1,2-azaborine is described along with a quantitative kinetic comparison of the reaction of the azaborine with its direct all-carbon analogue. The azaborine A rearranged in a clean, regioselective fashion and reacted faster than the all-carbon substrate B at all temperatures from 140–180 °C. Activation free energies were extracted from observed first-order rate constants (A: ΔG‡298K = 32.7 kcal mol−1; B: ΔG‡298K = 34.8 kcal mol−1) corresponding to a twenty fold faster rate for A at observed reaction temperatures. DFT calculations show that the rearrangement proceeds via a concerted six-membered transition state and that the electronic structure of the BN and CC rings is mostly responsible for the observed regioselectivity and relative reactivity.