Transient bicyclic aziridinium ions are known to undergo ring-expansion reactions, paving the way to functionalized nitrogen-containing heterocycles. In this study, the regioselectivity observed in the ring-expansion reactions of 1-azoniabicyclo[n.1.0]alkanes was investigated from a computational viewpoint to study the ring-expansion pathways of two bicyclic systems with different ring sizes. Moreover, several nucleophiles leading to different experimental results were investigated. The effect of solvation was taken into account using both explicit and implicit solvent models. This theoretical rationalization provides valuable insight into the observed regioselectivity and may be used as a predictive tool in future studies.

中文翻译：

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对双环叠氮鎓离子的区域选择性环扩展的理论见解†

已知瞬态双环叠氮鎓离子会发生扩环反应，从而为官能化的含氮杂环铺平了道路。在这项研究中，从计算的角度研究了在1-azoniabicyclo [ n .1.0]烷烃的扩环反应中观察到的区域选择性，以研究两个不同环尺寸的双环系统的扩环途径。此外，研究了几种导致不同实验结果的亲核试剂。使用显式和隐式溶剂模型均考虑了溶剂化的影响。这种理论上的合理化为观察到的区域选择性提供了宝贵的见识，并且可以用作未来研究中的预测工具。