Ji Heng, Ni Hui-Qiong, Zhi Peng, Xi Zi-Wei, Wang Wei, Shi Jian-Jun, Shen Yong-Miao
School of Chemical Engineering, Anhui University of Science and Technology, Huainan, P. R. China.
Org Biomol Chem. 2017 Jul 19;15(28):6014-6023. doi: 10.1039/c7ob01144j.
Perfluoroalkylation of N-alkylhydrazones has been achieved via visible light mediated photoredox reactions between the hydrazone and perfluoroalkyl iodide (RI). This protocol provides a convenient and efficient access to a series of perfluoroalkylated aromatic aldehyde hydrazones which tolerates a wide range of functional groups on the aromatic ring, and allows the use different types of primary and secondary perfluoroalkyl iodides with up to eight carbon atoms. Furthermore, aliphatic aldehyde hydrazones and N-monosubstituted hydrazones which are unreactive in previously reported hydrazone perfluoroalkylation reactions now take part in the reaction under our reaction conditions to give a satisfactory yield of products. Stern-Volmer quenching studies and spin-trapping experiments indicated that these reactions proceed by free radical addition of the R radical to the azomethine atom followed by one electron oxidation of the hydrazyl radical and deprotonation of the diazenium cation.
通过腙与全氟烷基碘化物（RI）之间的可见光介导光氧化还原反应，实现了N-烷基腙的全氟烷基化。该方法提供了一种方便且高效的途径来合成一系列全氟烷基化的芳香醛腙，这些腙能耐受芳香环上的多种官能团，并且允许使用不同类型的含多达八个碳原子的伯和仲全氟烷基碘化物。此外，脂肪醛腙和N-单取代腙在先前报道的腙全氟烷基化反应中无反应活性，但在我们的反应条件下现在能参与反应，以获得令人满意的产物收率。Stern-Volmer猝灭研究和自旋捕获实验表明，这些反应是通过R自由基加成到偶氮甲碱原子上形成自由基，随后肼基自由基发生单电子氧化以及重氮阳离子去质子化来进行的。
