Department of Chemistry, New York University, 24 Waverly Place, third floor, New York, New York 10003, United States.
J Am Chem Soc. 2022 Aug 31;144(34):15437-15442. doi: 10.1021/jacs.2c05648. Epub 2022 Aug 5.
Herein we report the anaerobic cleavage of alkenes into carbonyl compounds using nitroarenes as oxygen transfer reagents under visible light. This approach serves as a safe and practical alternative to mainstream oxidative cleavage protocols, such as ozonolysis and the Lemieux-Johnson reaction. A wide range of alkenes possessing oxidatively sensitive functionalities underwent anaerobic cleavage to generate carbonyl derivatives with high efficiency and regioselectivity. Mechanistic studies support that the transformation occurs via direct photoexcitation of the nitroarene followed by a nonstereospecific radical cycloaddition event with alkenes. This leads to 1,3,2- and 1,4,2-dioxazolidine intermediates that fragment to give the carbonyl products. A combination of radical clock experiments and photoNMR spectroscopy revealed the identities of the key radical species and the putative aryl dioxazolidine intermediates, respectively.
在这里，我们报告了使用硝基芳烃作为氧转移试剂，在可见光下将烯烃无氧裂解为羰基化合物。与主流的氧化裂解方法（如臭氧化和莱姆留-约翰逊反应）相比，这种方法是一种安全实用的替代方法。具有氧化敏感官能团的各种烯烃经历无氧裂解，以高效率和区域选择性生成羰基衍生物。机理研究支持该转化是通过硝基芳烃的直接光激发，然后与烯烃进行非立体专一性的自由基环加成反应来进行。这导致 1,3,2-和 1,4,2-二恶唑烷中间体，其断裂生成羰基产物。自由基钟实验和光 NMR 光谱的组合分别揭示了关键自由基物种和假定的芳基二恶唑烷中间体的身份。
