Department of Chemistry and Biology, Toronto Metropolitan University, 350 Victoria St, Toronto, ON, M5B 2K3, Canada.
Org Biomol Chem. 2022 Sep 21;20(36):7332-7337. doi: 10.1039/d2ob01247b.
We report on a direct photochemical method for the one-pot, catalyst- and additive-free synthesis of azoxybenzene and substituted azoxy derivatives from nitrobenzene building blocks. This reaction is conducted at room temperature and under air, and can be applied to substrates with a wide range of substituents. Yields of products derived from - and -substituted nitrobenzenes are typically good, while sterically encumbered -substituted substrates are not as fruitful. Photochemical Wallach rearrangement of generated azoxybenzenes to -hydroxyazoxybenzenes was observed in some cases, most markedly in selected -halogenated nitrobenzenes. Overall, this method provides an efficient, green pathway to highly value-added azoxybenzene products.
我们报告了一种直接光化学方法，可从硝基苯砌块一锅、无催化剂和添加剂地合成偶氮苯和取代偶氮衍生物。该反应在室温下、在空气中进行，可适用于具有广泛取代基的底物。衍生自 - 和 - 取代硝基苯的产物的产率通常很好，而空间位阻较大的 - 取代底物则不然。在某些情况下，生成的偶氮苯发生光化学反应的瓦拉赫重排，生成 - 羟基偶氮苯，在一些卤代硝基苯中尤为明显。总的来说，这种方法为高附加值的偶氮苯产品提供了一种高效、绿色的途径。
