Regioselective Synthesis of [3]Naphthylenes and Tuning of Their Antiaromaticity
Regioselective Synthesis of [3]Naphthylenes and Tuning of Their Antiaromaticity
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DOI：
10.1021/jacs.7b09222
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发表时间：
2017-11-08
影响因子：
15
通讯作者：
Xia, Yan
中科院分区：
文献类型：
--
作者：
Jin, Zexin;Teo, Yew Chin;Xia, Yan
含四元环丁二烯环（CBD）的多环共轭烃由于其抗芳香性而具有重要的理论和技术意义。然而，它们的综合一直具有挑战性，阻碍了对这些系统的探索和理解。我们报道了一系列前所未有的高收率的[3]萘区域异构体的有效合成，其中三个萘通过两个CBD以线性、角向和弯曲的区域连接性稠合。它们的合成是通过二溴萘和苯并氧-anorbornadienes之间的区域选择性催化芳烃-异戊二烯成环（CANAL），然后芳构化来实现的。[3]萘的区域异构体表现出明显的光电性质。独立于核的化学位移计算，NMR光谱，和X-射线晶体学揭示了强烈的影响的融合模式上的本地反芳香性和芳香性在融合CBD和萘，分别。因此，我们的合成策略允许容易地获得扩展的CBD融合的π-系统，具有可调的局部反芳香性和芳香性。
Polycyclic conjugated hydrocarbons containing four-membered cyclobutadienoids (CBDs) are of great fundamental and technical interest due to the antiaromaticity brought by CBD circuits. However, their synthesis has been challenging, hampering the exploration and understanding of such systems. We report efficient synthesis of a series of unprecedented [3]naphthylene regioisomers in high yields, where three naphthalenoids are fused through two CBDs in linear, angular, and bent regioconnectivity. Their synthesis was enabled by exclusively regioselective catalytic arene-norbornene annulation (CANAL) between dibromonaphthalenes and benzoox-anorbornadienes, followed by aromatization. [3]Naphthylene regioisomers exhibited distinct optoelectronic properties. Nucleus-independent chemical shift calculations, NMR spectroscopy, and X-ray crystallography revealed the strong effect of the fusion pattern on the local antiaromaticity and aromaticity in fused CBDs and naphthalenoids, respectively. Thus, our synthetic strategy allows facile access to extended CBD-fused pi-systems with tunable local antiaromaticity and aromaticity.