Application of Electrochemical Processes to Classical Iodocyclisation: Utility for Selectivity and Mechanistic Insight
Application of Electrochemical Processes to Classical Iodocyclisation: Utility for Selectivity and Mechanistic Insight
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DOI：
10.1002/celc.201901502
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发表时间：
2019-09
期刊：
影响因子：
4
通讯作者：
Diyuan Li;Peter W. Seavill;Jonathan D. Wilden
中科院分区：
文献类型：
--
作者：
Diyuan Li;Peter W. Seavill;Jonathan D. Wilden
通过原位和“按需”电化学生成这些物质，可以避免处理 I2 等元素卤素的危险和困难。这种方法的优点包括以稳定的速率将卤素引入反应混合物中，确保低浓度以防止反应性芳环的卤化。我们还证明，促进该反应所需的路易斯酸，即锌（II）盐，也可以以清洁和节能的方式从镀锌石墨电极原位生成。机理研究表明了一种不寻常的途径，它为碘环化提供了选择性，而没有经常出现问题的芳环亲电子芳香族碘化。
The hazards and difficulties of handling elemental halogens such as I2can be circumvented through the electrochemical generation of these species in situ and ‘on‐demand’. Advantages of this approach include the halogen being introduced into the reaction mixture at a steady rate, ensuring low concentrations to prevent halogenation of reactive aromatic rings. We also demonstrate that the Lewis acid required to promote this reaction, a Zn(II) salt, can also be generated in situ from a zinc‐coated graphite electrode in a clean and energy‐efficient manner. Mechanistic studies indicate an unusual pathway, which provides selectivity for the iodocyclisation without the often‐problematic electrophilic aromatic iodination of the aryl ring.