The [4 + 1] cycloaddition (41CA) and [2 + 1] cycloaddition (21CA) reactions of the α‐halogeno‐nitroalkenes with carbene have been studied using the molecular electron density theory through density functional theory calculations at the MPWB1K(PCM)/6‐311G(d,p) computational level. The 41CA reaction take place through a polar two‐step mechanism involving the formation of a zwitterionic intermediate. The competitive 21CA reaction path proceeds according to nonconcerted two‐stage one‐step. Bonding evolution theory analysis of 41CA reaction allows the distinguishing of four groups along the reaction path. The reaction begins with rupture of the CC double bond of the alkene moiety and formation of the pseudoradical center. Formation of the OC and CC new single bonds begins in subsequent phases. In the last stage of the 41CA reaction path, we observed the formation of an NC new double bond. In the case of 21CA reaction path, we observed the successive rupture of the CC double bond of the alkene moiety, formation of CC new single bond and pseudoradical center, and creation of a second CC single bond.

中文翻译：

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从分子电子密度理论的角度了解共轭硝基烯烃与亲电卡宾体系之间逐步[4 +1]环加成反应的独特性

使用分子电子密度理论，通过密度泛函理论计算，在MPWB1K（PCM）上研究了α-卤代-硝基烯烃与卡宾的[4 +1]环加成（41CA）和[2 +1]环加成（21CA）反应。 / 6-311G（d，p）计算级别。41CA反应通过极性两步机制进行，涉及两性离子中间体的形成。竞争性21CA反应路径按照未经证实的两阶段第一步进行。对41CA反应的键演化理论分析可以区分沿着反应路径的四个基团。反应开始与C的破裂烯烃部分和形成的的C双键pseudoradical中心。将O的形成 C和C 新的单键在后续阶段开始。在41CA反应路径的最后阶段，我们观察到的N的形成 C新型双键。在21CA反应路径的情况下，我们观察到C的连续破裂烯烃部分，形成的C的C双键 C新型单键和pseudoradical一个第二个C的中心，与创作 C单键。