Access to -Arylglycines by Umpolung Carboxylation of Aromatic Imines with Carbon Dioxide
Access to -Arylglycines by Umpolung Carboxylation of Aromatic Imines with Carbon Dioxide
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DOI：
10.1002/chem.201604623
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发表时间：
2016-11-21
影响因子：
4.3
通讯作者：
Lu, Xiao-Bing
中科院分区：
文献类型：
--
作者：
Guo, Chun-Xiao;Zhang, Wen-Zhen;Lu, Xiao-Bing
通过一种极性反转羧化反应，实现了一种从芳香亚胺和二氧化碳高效合成α -芳基甘氨酸衍生物的无过渡金属的直接方法。在叔丁醇钾和18 - 冠 - 6存在下，各种取代的二苯甲亚胺能与二氧化碳顺利地进行羧化反应，以良好到较高的产率得到相应的羧化产物。除了提高叔丁醇钾在四氢呋喃中的溶解性外，18 - 冠 - 6在抑制逆质子化或1,3 - 质子迁移异构化以及稳定羧化中间体方面也起着关键作用。
A straightforward and transition-metal-free approach for the efficient synthesis of -arylglycine derivatives from aromatic imines and carbon dioxide was enabled by an umpolung carboxylation reaction. Various substituted diphenylmethimines underwent the carboxylation smoothly with carbon dioxide in the presence of potassium tert-butoxide and 18-crown-6 to give the corresponding carboxylated products in good to high yields. Besides the enhancement of the solubility of potassium tert-butoxide in THF, 18-crown-6 also plays key roles in suppressing the reverse protonation or 1, 3-proton shift isomerization as well as by stabilizing the carboxylated intermediate.