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Experimental and Computational Studies on Stepwise Reactions of Diaryldiazomethanes with Electron-Deficient Dimethyl (E)- and (Z)-2,3-Dicyanobutenedioates
European Journal of Organic Chemistry ( IF 2.8 ) Pub Date : 2018-08-17 , DOI: 10.1002/ejoc.201800837
Grzegorz Mlostoń 1 , Małgorzata Celeda 1 , Radomir Jasiński 2 , Heinz Heimgartner 3
Affiliation  

Electron-deficient dimethyl (E)- and (Z)-2,3-dicyanobutenedioates (dimethyl dicyanofumarate and dicyanomaleate, respectively) react with diaryldiazomethanes at room temperature under spontaneous evolution of N2. The type of the products strongly depends on the structure of the diazo compound. Whereas diphenyldiazomethane and its bis(4-methoxy) derivative yield cyclopropanes, sterically crowded 5-diazo-5H-dibenzo[a,d]cycloheptane derivatives afford either the dimer of the carbene formed via N2 elimination or the adduct of the carbene onto the starting diazo compound. The course of the studied reactions is rationalized by stepwise mechanisms initiated by the formation of a C–N bond. A cascade of reactions leads to the corresponding cyclopropanes or to release of a carbene species. The formation of a pyrazole via [3+2]-cycloaddition (32CA) is observed only in reactions with (trimethyl- silyl)diazomethane, which behaves similar to the parent diazomethane. The proposed mechanisms were analyzed computationally using the DFT method.

中文翻译:

二芳基重氮甲烷与缺电子二甲基 (E)-和 (Z)-2,3-二氰基丁二酸酯的逐步反应的实验和计算研究

缺电子二甲基 (E)- 和 (Z)-2,3- 二氰基丁二酸酯(分别为二氰基富马酸二甲酯和二氰基苹果酸二甲酯)在室温下在 N2 的自发放出下与二芳基重氮甲烷反应。产物的类型很大程度上取决于重氮化合物的结构。而二苯基重氮甲烷及其双(4-甲氧基)衍生物产生环丙烷,空间上拥挤的 5-重氮-5H-二苯并[a,d]环庚烷衍生物提供通过 N2 消除形成的卡宾的二聚体或卡宾的加合物到起始重氮化合物。所研究的反应过程通过形成 C-N 键引发的逐步机制合理化。一连串的反应导致相应的环丙烷或卡宾物质的释放。仅在与(三甲基-甲硅烷基)重氮甲烷的反应中观察到通过 [3+2]-环加成 (32CA) 形成吡唑,其行为类似于母体重氮甲烷。使用 DFT 方法对所提出的机制进行了计算分析。
更新日期:2018-08-17
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