N-Halosuccinimide/BF3-H2O, efficient electrophilic halogenating systems for aromatics
N-Halosuccinimide/BF3-H2O, efficient electrophilic halogenating systems for aromatics
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DOI：
10.1021/ja0465247
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发表时间：
2004-12-08
影响因子：
15
通讯作者：
Olah, GA
中科院分区：
文献类型：
--
作者：
Prakash, GKS;Mathew, T;Olah, GA
N-卤代琥珀酰亚胺 (NXS, 1) 在三氟甲磺酸和 BF3-H2O 中被有效活化，从而使失活的芳族化合物发生卤化。由于BF3-H2O更经济、易于制备、非氧化性且具有足够高的酸度（-H-0接近12，仅略低于三氟甲磺酸），因此开发了NXS/BF3-H2O的高效新型亲电试剂组合。 B3LYP/6-311++G**//B3LYP/6-31G* 水平的 DFT 计算表明，质子化的 N-卤代琥珀酰亚胺在较高的酸度下经历进一步的原溶剂化，形成反应性超亲电子物质，该物质能够将 X+ 从质子化形式的 NXS 转移到芳香族底物，或者形成高反应性和溶剂化的 X+，其很容易与芳香族底物反应。 BF3-H2O 复合物的结构方面也进行了研究。
N-Halosuccinimides (NXS, 1) are efficiently activated in trifluoromethanesulfonic acid and BF3-H2O, allowing the halogenations of deactivated aromatics. Because BF3-H2O is more economic, easy to prepare, nonoxidizing, and offers sufficiently high acidity (-H-0 approximate to 12, only slightly lower than that of trifluoromethanesulfonic acid), an efficient new electrophilic reagent combination of NXS/BF3-H2O has been developed. DFT calculations at the B3LYP/6-311++G**//B3LYP/6-31G* level suggest that protonated N-halosuccinimides undergo further protosolvation at higher acidities to reactive superelectrophilic species capable either in the transfer of X+ from the protonated forms of NXS to the aromatic substrate or in forming a highly reactive and solvated X+ which would readily react with the aromatic substrates. Structural aspects of the BF3-H2O complex have also been investigated.