Oxidopyridinium Cycloadditions Revisited: A Combined Computational and Experimental Study on the Reactivity of 1-(2-Pyrimidyl)-3-oxidopyridinium Betaine
Oxidopyridinium Cycloadditions Revisited: A Combined Computational and Experimental Study on the Reactivity of 1-(2-Pyrimidyl)-3-oxidopyridinium Betaine
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重新审视氧化吡啶鎓环加成：1-(2-嘧啶基)-3-氧化吡啶鎓甜菜碱反应性的联合计算和实验研究
DOI：
10.1021/acs.joc.2c02971
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Takeshi Yasui
中科院分区：
文献类型：
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作者：
Yoshihiko Yamamoto;Yudai Shizume;Syunji Tazawa;Takeshi Yasui
为了研究N-取代基对氧化吡啶甜菜碱反应活性和选择性的影响，我们对N-甲基马来酰亚胺和苊烯的环加成反应进行了密度泛函理论（DFT）计算.理论预期结果与实验结果进行了比较。随后，我们证明了1-（2-嘧啶基）-3-氧化吡啶鎓可用于与各种缺电子烯烃、乙炔二羧酸二甲酯、苊烯和苯乙烯的（5 + 2）环加成。此外，1-（2-嘧啶基）-3-氧化吡啶鎓与6，6-二甲基五富烯的环加成反应的DFT分析表明，尽管实验上只观察到（5 + 6）环加合物，但可能存在涉及（5 + 4）/（5 + 6）双峰过渡态的途径分叉。在1-（2-嘧啶基）-3-氧化吡啶鎓与2，3-二甲基丁-1，3-二烯的反应中观察到相关的（5 + 4）环加成反应。
To investigate the effect of N-substituents on their reactivity and selectivity of oxidopyridinium betaines, we performed density functional theory (DFT) calculations of model cycloadditions withN-methylmaleimide and acenaphthylene. The theoretically expected results were compared with the experimental results. Subsequently, we demonstrated that 1-(2-pyrimidyl)-3-oxidopyridinium can be used for (5 + 2) cycloadditions with various electron-deficient alkenes, dimethyl acetylenedicarboxylate, acenaphthylene, and styrene. In addition, a DFT analysis of the cycloaddition of 1-(2-pyrimidyl)-3-oxidopyridinium with 6,6-dimethylpentafulvene suggested the possibility of pathway bifurcations involving a (5 + 4)/(5 + 6) ambimodal transition state, although only (5 + 6) cycloadducts were experimentally observed. A related (5 + 4) cycloaddition was observed in the reaction of 1-(2-pyrimidyl)-3-oxidopyridinium with 2,3-dimethylbut-1,3-diene.