PDF(Pubmed)
Abstract：
Arynes are fleeting, high-energy intermediates that undergo myriad trapping reactions by nucleophiles. Their unusual reactivity compared to other electrophiles can spur unexpected mechanistic pathways enroute to the formation of benzenoid products. Herein we explore a particularly unique case of thermally generated arynes reacting with phosphoranes to form helical dibenzothiophenes and -selenophenes. Multiple new helical polycyclic aromatic products are reported. DP4+ and X-ray crystallographic analysis were used in tandem to confirm the structural topologies of selected products and to demonstrate the utility of DP4+ for distinguishing between isomeric polycyclic aromatic compounds. Lastly, we discuss a plausible mechanism consistent with DFT computations that accounts for the product formation; namely, ligand coupling (i.e., reductive elimination) within a hypervalent, pentacarbon-ligated σ-phosphorane furnishes the dibenzothio- or dibenzoselenophene.
摘要：
阿里恩斯转瞬即逝，经历无数亲核试剂捕获反应的高能中间体。与其他亲电试剂相比，它们的异常反应性会刺激意外的机械途径，从而形成苯类化合物。在本文中，我们探索了一种特别独特的情况，即热生成的炔与正膦反应形成螺旋二苯并噻吩和-硒苯。报道了多种新的螺旋多环芳烃产品。DP4和X射线晶体学分析串联使用，以确认所选产品的结构拓扑，并证明DP4用于区分异构多环芳族化合物的实用性。最后,我们讨论了一种与DFT计算相一致的合理机制，该机制解释了产品的形成；即配体偶联(即，还原消除)在高价内，五碳连接的s-正膦提供二苯并硫基-或二苯并硒酚。
