One-Pot Synthesis of Pyrazoles through a Four-Step Cascade Sequence

Authors

  • Lu Hao,

    1. Department of Chemistry and Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian (P.R. China), Fax: (+86) 592-2180318
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  • Jun-Jie Hong,

    1. Department of Chemistry and Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian (P.R. China), Fax: (+86) 592-2180318
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  • Jun Zhu,

    1. Department of Chemistry and Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian (P.R. China), Fax: (+86) 592-2180318
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  • Prof. Zhuang-Ping Zhan

    Corresponding author
    1. Department of Chemistry and Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian (P.R. China), Fax: (+86) 592-2180318
    • Department of Chemistry and Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian (P.R. China), Fax: (+86) 592-2180318
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Abstract

A one-pot synthesis of 3,4,5- and 1,3,5-pyrazoles from tertiary propargylic alcohols and para-tolylsulfonohydrazide has been accomplished. The pyrazoles are formed through a four-step cascade sequence, including FeCl3-catalyzed propargylic substitution, aza-Meyer–Schuster rearrangement, base-mediated 6π electrocyclization, and thermal [1,5] sigmatropic shift. In this reaction, the 3,4,5- and 1,3,5-pyrazoles are produced selectively according to different substituents in the starting alcohols.

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