Kącka-Zych Agnieszka
Institute of Organic Chemistry and Technology, Cracow University of Technology, Warszawska 24, 31-155, Cracow, Poland.
J Mol Graph Model. 2020 Jun;97:107549. doi: 10.1016/j.jmgm.2020.107549. Epub 2020 Jan 28.
The structure and the participation of the N-methoxy-N-[bis(methoxycarbonyl)methylene]amine N-oxide as model push-pull nitronate 1 with nitroethylene 2 in [3 + 2] cycloaddition (32CA) reaction have been analyzed within the Molecular Electron Density Theory (MEDT) using Density Functional Theory (DFT) calculations at the B3LYP(PCM)/6-31G(d) level. Topological analysis of the Electron Localization Function (ELF) of nitronate 1 reveals that this compound has pseudoradical center, while the conceptual DFT reactivity indices characterizes this three-atom-component (TAC) as a strong electrophile. The analyzed 32CA reaction takes place through a one-step mechanism. A Bonding Evolution Theory (BET) study of the more favorable reaction path associated with the 32CA reaction of nitronate 1 with nitroethylene 2 indicates that it is associated with a non-concerted two-stage one-step mechanism, in which the activation energy is mainly related with to the initial formation of the O3-C4 single bond. In the case of this reaction, an additional mechanism with formation of intermediate 7 is also found.
在分子电子密度理论（MEDT）框架内，使用密度泛函理论（DFT）在B3LYP(PCM)/6-31G(d)水平上进行计算，分析了作为模型推拉式硝酮1的N-甲氧基-N-[双（甲氧基羰基）亚甲基]胺N-氧化物与硝基乙烯2在[3 + 2]环加成（32CA）反应中的结构和参与情况。对硝酮1的电子定域函数（ELF）进行拓扑分析表明，该化合物具有假自由基中心，而概念性DFT反应性指数将这个三原子组分（TAC）表征为强亲电试剂。所分析的32CA反应通过一步机理进行。对与硝酮1和硝基乙烯2的32CA反应相关的更有利反应路径进行的键演化理论（BET）研究表明，它与非协同的两阶段一步机理相关，其中活化能主要与O3-C4单键的初始形成有关。在该反应中，还发现了一种形成中间体7的额外机理。
