Lang Xianjun, Zhao Jincai
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China.
Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
Chem Asian J. 2018 Mar 16;13(6):599-613. doi: 10.1002/asia.201701765. Epub 2018 Feb 19.
Visible light has risen to become a very important facilitator for selective radical reactions enabled by well-cognized photocatalysts. The renaissance of visible-light photocatalysis on this matter partly relies on integrating it with other fields of catalysis. In parallel, 2,2,6,6-tetramethylpiperidin N-oxide (TEMPO), a quintessential persistent radical, has a wide range of uses owing to its exceptional redox behavior, which gives rise to its latest prominence in catalysis. Therefore, integrating the catalysis of TEMPO with photocatalysis to perform visible-light-induced selective reactions becomes a very convenient marriage of merits. In this context, the integration of different types of photocatalysts, including metal complexes, metal-free organic dyes, and semiconductors, with TEMPO for outstanding organic transformations will be summarized. To expand further the catalytic repertoire, the integration of TEMPOH analogues such as NHPI (N-hydroxyphthalimide) and NHS (N-hydroxysuccinimide) with photocatalysis will also be discussed. Hopefully, these advances will pave the way for more breakthroughs by integrating TEMPO and its analogues with photocatalysis to lead to a valuable blueprint for visible-light-induced selective organic transformations.
可见光已成为一种非常重要的促进剂，可实现由广为人知的光催化剂引发的选择性自由基反应。在此方面，可见光光催化的复兴部分依赖于将其与其他催化领域相结合。与此同时，2,2,6,6-四甲基哌啶氮氧化物（TEMPO）作为一种典型的持久性自由基，因其独特的氧化还原行为而具有广泛用途，这也使其在催化领域崭露头角。因此，将TEMPO催化与光催化相结合以进行可见光诱导的选择性反应，成为了一种优势互补的便捷结合方式。在此背景下，将总结不同类型的光催化剂，包括金属配合物、无金属有机染料和半导体，与TEMPO相结合以实现出色的有机转化。为进一步拓展催化范围，还将讨论TEMPOH类似物，如N-羟基邻苯二甲酰亚胺（NHPI）和N-羟基琥珀酰亚胺（NHS）与光催化的结合。希望这些进展将为通过将TEMPO及其类似物与光催化相结合实现更多突破铺平道路，从而为可见光诱导的选择性有机转化提供一份有价值的蓝图。
