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, Wen-Wei Lin

Research output: Contribution to journalArticle

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

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Pyrazoles
Isoxazoles
phosphine
Oximes
acylation
Acylation
Alkenes
synthesis
phosphines
alkenes
Chlorides
chlorides

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry

Cite this

An Intramolecular Wittig Approach toward Heteroarenes : Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes. / Khairnar, Pankaj V.; Lung, Tsai Hui; Lin, Yi Jung; Wu, Chi Yi; Koppolu, Srinivasa Rao; Edukondalu, Athukuri; Karanam, Praneeth; Lin, Wen-Wei.

In: Organic Letters, Vol. 21, No. 11, 07.06.2019, p. 4219-4223.

Research output: Contribution to journalArticle

Khairnar, PV, Lung, TH, Lin, YJ, Wu, CY, Koppolu, SR, Edukondalu, A, Karanam, P & Lin, W-W 2019, 'An Intramolecular Wittig Approach toward Heteroarenes: Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes', Organic Letters, vol. 21, no. 11, pp. 4219-4223. https://doi.org/10.1021/acs.orglett.9b01395
Khairnar, Pankaj V. ; Lung, Tsai Hui ; Lin, Yi Jung ; Wu, Chi Yi ; Koppolu, Srinivasa Rao ; Edukondalu, Athukuri ; Karanam, Praneeth ; Lin, Wen-Wei. / An Intramolecular Wittig Approach toward Heteroarenes : Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes. In: Organic Letters. 2019 ; Vol. 21, No. 11. pp. 4219-4223.
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