邱丽华副教授与徐新芳教授合作在 Chem. Eur. J. 上发表研究论文

Copper- or Thermally Induced Divergent Outcomes: Synthesis of 4-Methyl 2H-Chromenes and Spiro-4H-Pyrazoles

Yang Zheng[a], Lihua Qiu*[a](邱丽华), Kemiao Hong[a], Shanliang Dong[a], and Xinfang Xu*[a, b](徐新芳)

  

[a] Key Laboratory of Organic Synthesis of Jiangsu Province, College of

Chemistry, Chemical Engineering and Materials ScienceSoochow University, Suzhou 215123 (P.R. China)

[b] State Key Laboratory of Elemento-organic ChemistryNankai University, Tianjin 300071 (P.R. China)

  

Chem. Eur. J. 2018, 24, 6705 --6711

  

An unprecedented divergent outcome transformation of alkyne tethered Nsulfonyl hydrazones is reported, which provides a direct and effective access to 4methyl 2Hchromene derivatives and spiro4Hpyrazoles 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 3Hpyrazole, 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 3Hpyrazole, which was isolated and confirmed by single crystal Xray diffraction analysis for the first time.

  

链接:https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201704759