Jiang Xiao-Lei, Liu Qing, Wei Kua-Fei, Zhang Ting-Ting, Ma Guang, Zhu Xiu-Hong, Ru Guang-Xin, Liu Lijie, Hu Lian-Rui, Shen Wen-Bo
College of Sciences and College of Forestry, Henan Agricultural University, Zhengzhou, 450002, China.
Sanmenxia Polytechnic, Sanmenxia, Henan, 472000, China.
Commun Chem. 2023 Feb 20;6(1):35. doi: 10.1038/s42004-023-00840-6.
General access to highly valuable seven-membered rings via Büchner-type reaction remains a formidable challenge. Here we report a Cu-catalyzed intermolecular oxidation of alkynes using N-oxides as oxidants, which enables expedient preparation of valuable benzo[6,7]azepino[2,3-b]quinolines and pyridine-based diones. Importantly, in contrast to the well-established gold-catalyzed intermolecular alkyne oxidation, the dissociated pyridine or quinoline partner could be further utilized to construct N-heterocycles in this system and the reaction most likely proceeds by a Büchner-type ring expansion pathway. A mechanistic rationale for this cascade cyclization is supported by DFT calculations.
通过布赫纳型反应普遍获得高价值的七元环仍然是一项艰巨的挑战。在此，我们报道了一种以N-氧化物作为氧化剂的铜催化炔烃分子间氧化反应，该反应能够便捷地制备有价值的苯并[6,7]氮杂环庚并[2,3-b]喹啉和吡啶二酮。重要的是，与成熟的金催化炔烃分子间氧化反应不同，在该体系中，解离的吡啶或喹啉配体可进一步用于构建氮杂环，并且该反应很可能通过布赫纳型扩环途径进行。密度泛函理论计算支持了这种级联环化反应的机理原理。
