光促芳香烃甲基化反应研究进展

Recent Progress of Photocatalytic Methylation of Arenes

甲基化反应是有机合成和药物化学领域进行结构修饰的一类重要反应.在药物分子结构中引入甲基有助于提高其与生物大分子的结合亲和力、生物溶解度和代谢稳定性,这种现象被称为"神奇的甲基效应".近年来,可见光促进的氧化还原反应得到了不断发展,该类反应已经成为有机合成化学的一个重要方法.这一新颖的催化模式通过单电子传递或者能量转移等方式活化底物,得到高活性反应中间体,从而实现多类型重要转化.近来,已有多例利用可见光氧化还原催化体系实现了芳香烃的甲基化反应的报道,为向芳烃中引入甲基提供了新颖、高效的途径.系统地阐述了可见光促进的芳香烃甲基化反应的研究进展,讨论了部分反应的反应机理.

Methylation of arenes is one of the versatile approaches to achieve structural modification in organic and medicinal chemistry. Installation of a methyl group onto an aromatic ring can lead to significant improvenent of the physical properties and biological activity of this molecule, thusly the effect oftentimes is called the"magic methyl effect". During the past few years, visible-light-induced photocatalysis has emerged as a powerful tool for the development of efficient transformations in organic synthesis. Compared to traditional radical mediated reactions, the use of visible light as energy input is more environmentally benign. Recently, a series of aryl methylation reactions enabled by visible light photoredox catalysis have been reported and applied in the synthesis of pharmaceutically-interested products. In this review, the recent progress of visible-light-induced aryl methylation reactions is briefly summaried, with discussions of different reaction pathways.