An Intramolecular Wittig Approach toward Heteroarenes: Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes

Pankaj V. Khairnar, Tsai Hui Lung, Yi Jung Lin, Chi Yi Wu, Srinivasa Rao Koppolu, Athukuri Edukondalu, Praneeth Karanam, Wenwei Lin

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

α-Halohydrazones/ketoximes are transformed into trisubstituted pyrazoles/disubstituted isoxazoles by treatment with phosphine, acyl chloride, and a base. Mechanistic investigations revealed the in situ formation of azo/nitroso olefin intermediates which underwent a tandem phospha-Michael/N- or O-acylation/intramolecular Wittig reaction to afford the heteroarenes in moderate to good yields. Further, proper functionalization of α-haloketoximes and a change of conditions allowed the chemoselective synthesis of chromenone-oximes as well as rearranged isoxazoles, thereby realizing a diversity-oriented synthesis.

Original languageEnglish
Pages (from-to)4219-4223
Number of pages5
JournalOrganic Letters
Volume21
Issue number11
DOIs
Publication statusPublished - 2019 Jun 7

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry

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    Khairnar, P. V., Lung, T. H., Lin, Y. J., Wu, C. Y., Koppolu, S. R., Edukondalu, A., Karanam, P., & Lin, W. (2019). An Intramolecular Wittig Approach toward Heteroarenes: Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes. Organic Letters, 21(11), 4219-4223. https://doi.org/10.1021/acs.orglett.9b01395