Azepinone derivatives are privileged in organic synthesis and pharmaceuticals. Synthetic approaches to these frameworks are limited to complex substrates, strong bases, high power UV light or noble metal catalysis. We herein report a mild synthesis of azepinone derivatives by a photochemical generation of 2-aryloxyaryl nitrene, [2 + 1] annulation, ring expansion/water addition cascade reaction without using any metal catalyst. Among the different nitrene precursors tested, 2-aryloxyaryl azides performed best under blue light irradiation and Brønsted acid catalysis. The reaction scope is broad and the obtained products underwent divergent transformations to afford other related compounds. A computational study suggests a pathway involving a step-wise aziridine formation, followed by a ring-expansion to the seven-membered heterocycle. Finally, water is added in a regio-selective manner, this is accelerated by the added TsOH.

Azepinone 衍生物在有机合成和制药方面享有特权。这些框架的合成方法仅限于复杂的底物、强碱、高功率紫外光或贵金属催化。我们在此报道了通过光化学生成 2-芳氧基芳基氮烯、[2 + 1] 环化、扩环/水加成级联反应而不使用任何金属催化剂来温和合成氮杂庚酮衍生物。在测试的不同氮烯前体中，2-芳氧基芳基叠氮化物在蓝光照射和布朗斯台德酸催化下表现最佳。反应范围广，所得产物经过不同的转化得到其他相关化合物。一项计算研究表明，一条途径涉及逐步形成氮丙啶，然后环扩展为七元杂环。最后，