Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University , Wuhan 430079, P. R. China.
Org Lett. 2017 Sep 1;19(17):4584-4587. doi: 10.1021/acs.orglett.7b02182. Epub 2017 Aug 23.
The iodine-catalyzed catalytic formal [3 + 3 + 1] cycloaddition for the preparation of a seven-membered O-heterocyclic ring is presented, which is an achievement of methyl and carbonyl group reactivity of 3-methyl-5-pyrazolones to forge the C-O bond. This novel protocol provides a straightforward and efficient access to structurally diverse fused O-heterocycles through an iodine-catalyzed iodination/Kornblum oxidation/oxidative coupling/C-O bond formation cascade reaction. This approach demonstrates the unprecedented concurrent realization of the unique reactivity among the methyl, methylene, and carbonyl groups in 3-methyl-5-pyrazolones for the construction of 2,3-dihydrooxepine rings. Moreover, a broad substrate scope displays a graceful diversity-oriented synthetic approach.
碘催化的催化形式 [3 + 3 + 1] 环加成反应用于制备七元 O-杂环，这是 3-甲基-5-吡唑酮的甲基和羰基反应性的成就，用于形成 C-O 键。该新方法通过碘催化的碘化/Kornblum 氧化/氧化偶联/C-O 键形成级联反应，为结构多样的稠合 O-杂环提供了一种直接有效的方法。该方法证明了 3-甲基-5-吡唑酮中甲基、亚甲基和羰基之间独特反应性的前所未有的同时实现，用于构建 2,3-二氢氧杂环戊烷环。此外，广泛的底物范围展示了一种优雅的、多样化导向的合成方法。
