Direct Photocatalytic Synthesis of Medium-Sized Lactams by C−C Bond Cleavage
作者:Na Wang、Qiang-Shuai Gu、Zhong-Liang Li、Zhuang Li、Yu-Long Guo、Zhen Guo、Xin-Yuan Liu
DOI:10.1002/anie.201808890
日期:2018.10.22
Reported is a novel two‐step ring‐expansion strategy for expeditious synthesis of all ring sizes of synthetically challenging (hetero)aryl‐fused medium‐sized lactams from readily available 5–8‐membered cyclic ketones. This step‐economic approach features a remote radical (hetero)aryl migration from C to N under visible‐light conditions. Broad substrate scope, good functional‐group tolerance, high efficiency
Construction of medium-sized ring compounds remains challenging in synthetic chemistry. Herein, we describe the synthesis of medium-sized lactams via a photoinduced ringexpansion of benzo-fused cyclicketones using graphitic carbon nitride (g-C3N4) as a photocatalyst. The ringexpansion protocol provided an efficient access to 8–10-membered lactams in good yields and displayed good tolerance to a
中等尺寸环状化合物的构建在合成化学中仍然具有挑战性。在此,我们描述了使用石墨氮化碳(gC 3 N 4 )作为光催化剂,通过苯并稠合环酮的光诱导扩环来合成中等尺寸的内酰胺。扩环方案以良好的产率有效地获得 8-10 元内酰胺,并对一系列官能团表现出良好的耐受性。机理研究表明,光化学反应是通过氮自由基的中介进行的,氮自由基是通过氧化氢原子转移(HAT)过程产生的。