Rational Design and Synthesis of Unsaturated Se-Containing Osmacycles with sigma-Aromaticity
Rational Design and Synthesis of Unsaturated Se-Containing Osmacycles with sigma-Aromaticity
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具有σ芳香性的不饱和含硒锇环的合理设计与合成
DOI：
10.1002/chem.201703870
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Zhu Jun
中科院分区：
文献类型：
--
作者：
Zhou Xiaoxi;Wu Jingjing;Hao Yulei;Zhu Congqing;Zhuo Qingde;Xia Haiping;Zhu Jun
分离最简单的4个π三元杂环(1H-azirine、oxirene、thiirene和seenirene)仍然是一个巨大的挑战，因为它们具有π抗芳香性和显著的环应变。在这里，我们通过密度泛函理论(DFT)计算证明了过渡金属片段的引入可以同时稳定抗芳香族的硒和戊烯骨架。实验验证得到了具有显著热稳定性的含Se金属多环化合物--六茂硒化合物。确定了金属多环中的蛇纹烯单元是σ芳香性在不饱和含Se环中占优势的第一个例子。我们的结果不仅突出了过渡金属的显著稳定作用，而且拓宽了不饱和环中σ芳香性的范围，这一范围传统上被保留在π芳香性领域。
Isolation of the simplest 4π three‐membered heterocycles (1H‐azirine, oxirene, thiirene, and selenirene) remains a big challenge due to their π‐antiaromaticity and significant ring strain. Here we demonstrate that the incorporation of a transition‐metal fragment could stabilize the antiaromatic selenirene and pentalene frameworks simultaneously by density functional theory (DFT) calculations. Experimental verification leads to the Se‐containing metallapolycycles, osmapentaloselenirenes, with remarkable thermal stability. The osmaselenirene unit in the metallapolycycle is determined to be the first example of σ‐aromaticity dominating in an unsaturated Se‐containing ring. Our results not only highlight a remarkable stabilization by the transition‐metal but also widen the scope of σ‐aromaticity in unsaturated rings, which is traditionally reserved for the domain of π‐aromaticity.