Photoredox/Cobalt-Catalyzed Cascade Oxidative Synthesis of 2,5-Disubstituted 1,3,4-Oxadiazoles under Oxidant-Free Conditions
作者:Jun-Li Li、Hao-Yuan Li、Shan-Shan Zhang、Shigang Shen、Xiu-Long Yang、Xiaoying Niu
DOI:10.1021/acs.joc.3c01078
日期:2023.11.3
An efficient oxidant-free, photoredox-mediated cascade cyclization strategy for the synthesis of 1,3,4-oxadiazoles by using an organo acridinium photocatalyst and a cobaloxime catalyst has been developed. Various acylhydrazones have been transformed into the corresponding 1,3,4-oxadiazole products in up to 96% yield, and H2 is the only byproduct. Mechanistic experiments and density functional theory
通过使用有机吖啶光催化剂和钴肟催化剂,开发了一种有效的无氧化剂、光氧化还原介导的级联环化策略,用于合成 1,3,4-恶二唑。各种酰腙已转化为相应的1,3,4-恶二唑产品,收率高达96%,H 2是唯一的副产物。机理实验和密度泛函理论 (DFT) 计算研究表明,光激发 Mes–Acr + *氧化以及去质子化产生的 π 自由基是以碳为中心的自由基,而不是以氧为中心的自由基,这是造成这种转变的原因。该方法的实用性突出是直接从市售醛和酰肼开始的一锅克级合成。