Hasegawa Eietsu, Tanaka Tsukasa, Izumiya Norihiro, Kiuchi Takehiro, Ooe Yuuki, Iwamoto Hajime, Takizawa Shin-Ya, Murata Shigeru
Department of Chemistry, Faculty of Science, Niigata University, 8050 Ikarashi-2, Nishi-ku, Niigata 950-2181, Japan.
Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
J Org Chem. 2020 Mar 20;85(6):4344-4353. doi: 10.1021/acs.joc.0c00038. Epub 2020 Mar 3.
An unprecedented photocatalytic system consisting of benzimidazolium aryloxide betaines (BI-ArO) and stoichiometric hydride reducing reagents was developed for carrying out desulfonylation reactions of -sulfonyl-indoles, -amides, and -amines, and α-sulfonyl ketones. Measurements of absorption spectra and cyclic voltammograms as well as density functional theory (DFT) calculations were carried out to gain mechanistic information. In the catalytic system, visible-light-activated benzimidazoline aryloxides (BIH-ArO), generated in situ by hydride reduction of the corresponding betaines BI-ArO, donate both an electron and a hydrogen atom to the substrates. A modified protocol was also developed so that a catalytic quantity of more easily prepared hydroxyaryl benzimidazolines (BIH-ArOH) is used along with a stoichiometric hydride donor to promote the photochemical desulfonylation reactions.
开发了一种由苯并咪唑鎓芳氧基甜菜碱（BI-ArO）和化学计量的氢化物还原试剂组成的前所未有的光催化体系，用于进行磺酰基吲哚、磺酰胺、磺酰基胺和α-磺酰基酮的脱磺酰化反应。进行了吸收光谱和循环伏安图的测量以及密度泛函理论（DFT）计算以获取机理信息。在该催化体系中，通过相应甜菜碱BI-ArO的氢化物还原原位生成的可见光活化苯并咪唑啉芳氧化物（BIH-ArO）将一个电子和一个氢原子都提供给底物。还开发了一种改进的方案，以便将催化量的更易于制备的羟基芳基苯并咪唑啉（BIH-ArOH）与化学计量的氢化物供体一起使用，以促进光化学脱磺酰化反应。
