Iodobenzene-Catalyzed Synthesis of Fully Functionalized NH-Pyrazoles and Isoxazoles from α,β-Unsaturated Hydrazones and Oximes via 1,2-Aryl Shift
作者:Vikram Singh、Deepak Kumar、Bal Krishna Mishra、Bhoopendra Tiwari
DOI:10.1021/acs.orglett.3c04057
日期:2024.1.12
An iodine(III)-catalyzed general method for the synthesis of fully functionalized NH-pyrazoles and isoxazoles from α,β-unsaturated hydrazones and oximes, respectively, via cyclization/1,2-aryl shift/aromatization/detosylation, has been developed. The reaction progresses through an anti-Baldwin 5-endo-trig cyclization. It gives direct access to an advanced intermediate for the preparation of valdecoxib
开发了一种碘(III)催化的通用方法,分别通过环化/1,2-芳基转移/芳构化/去托磺化,从α,β-不饱和腙和肟合成全官能化NH-吡唑和异恶唑。该反应通过抗-Baldwin 5-内-触发环化进行。它可以直接获得用于制备用于 COX 抑制的药物伐地昔布和帕瑞昔布的高级中间体。此外,还开发了一种在 TIPS-EBX 存在下进行吡唑N-炔基化的方法。