FeCl3 as an Ion-Pairing Lewis Acid Catalyst. Formation of Highly Lewis Acidic FeCl2+ and Thermodynamically Stable FeCl4 To Catalyze the Aza-Diels-Alder Reaction with High Turnover Frequency
FeCl3 as an Ion-Pairing Lewis Acid Catalyst. Formation of Highly Lewis Acidic FeCl2+ and Thermodynamically Stable FeCl4 To Catalyze the Aza-Diels-Alder Reaction with High Turnover Frequency
复制标题
FeCl3 作为离子对路易斯酸催化剂。
DOI：
10.1021/acs.orglett.8b03249
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发表时间：
2018
期刊：
影响因子：
5.2
通讯作者：
S.
中科院分区：
文献类型：
--
作者：
Tomifuji;R.; Maeda;K.; Takahashi;T.; Kurahashi;T.; Matsubara;S.
未活化的二烯和亚胺的aza-Diels-桤木反应是通过FeCl 3原位还原生成的离子对刘易斯酸催化剂[FeCl 2]+[FeCl 4]−的作用实现的。[FeCl 2]+[FeCl 4]−的独特高反应性归因于高度刘易斯酸性的FeCl 2+和化学稳定的FeCl 4-作为离子配对催化剂。基于同步加速器的X射线吸收精细结构测量提供了对所得到的离子配对铁络合物的构型和结构的基本见解。对非活化二烯和亚胺的aza-Diels-桤木反应中的“离子配对效应”进行了理论研究，分析了催化反应，并更好地理解了“离子配对效应”将简单的FeCl 3转化为高转换频率的刘易斯酸催化剂。
The aza-Diels–Alder reaction of nonactivated dienes and imines was realized through the action of the ion-paired Lewis acid catalyst [FeCl2]+[FeCl4]−generated by the in situ disproportionation of FeCl3. The uniquely high reactivity of [FeCl2]+[FeCl4]−was attributed to both the highly Lewis acidic FeCl2+and thermodynamically stable FeCl4–acting as an ion-paired catalyst. Synchrotron-based X-ray absorption fine structure measurements provided fundamental insights into the disproportionation and structure of the resulting ion-paired iron complex. A theoretical study was performed to analyze the catalytic reaction and better understand the “ion-pairing effect” which transforms simple FeCl3into a high turnover frequency Lewis acid catalyst in the aza-Diels–Alder reaction of nonactivated dienes and imines.