Key Laboratory of Organic Synthesis of Jiangsu Province, College of, Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China.
State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin, 300071, P.R. China.
Chemistry. 2018 May 7;24(26):6705-6711. doi: 10.1002/chem.201704759. Epub 2017 Nov 30.
An unprecedented divergent outcome transformation of alkyne tethered N-sulfonyl hydrazones is reported, which provides a direct and effective access to 4-methyl 2H-chromene derivatives and spiro-4H-pyrazoles in the presence of copper catalyst or under thermal conditions, respectively. The notable features of this process include readily available starting materials, an inexpensive copper catalyst, mild reaction conditions, broad substrate scope, diverse transformations and potential applications of these generated products. Mechanistic studies indicate that the 3H-pyrazole, which is generated via direct [3+2] cycloaddition, is the communal key intermediate of these two divergent transformations. To the best of our knowledge, this is the only example of sulfonation reaction that goes through a cascade process involving 3H-pyrazole, which was isolated and confirmed by single crystal X-ray diffraction analysis for the first time.
报道了一种前所未有的炔键连接的 N-磺酰腙的发散性结果转化，分别在铜催化剂或热条件下，为 4-甲基 2H-色烯衍生物和螺-4H-吡唑的直接有效合成提供了途径。该过程的显著特点包括易得的起始原料、廉价的铜催化剂、温和的反应条件、广泛的底物范围、多种转化以及这些生成产物的潜在应用。机理研究表明，通过直接[3+2]环加成生成的 3H-吡唑是这两种发散转化的共同关键中间体。据我们所知，这是首例通过涉及 3H-吡唑的级联过程进行磺化反应的例子，该过程首次通过单晶 X 射线衍射分析得到分离和证实。
