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

doi:10.1021/acs.orglett.9b01395

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^*

^*Corresponding author for this work

Department of Chemistry

Research output: Contribution to journal › Article › peer-review

52 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 language	English
Pages (from-to)	4219-4223
Number of pages	5
Journal	Organic Letters
Volume	21
Issue number	11
DOIs	https://doi.org/10.1021/acs.orglett.9b01395
Publication status	Published - 2019 Jun 7

ASJC Scopus subject areas

Biochemistry
Physical and Theoretical Chemistry
Organic Chemistry

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10.1021/acs.orglett.9b01395

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

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.",

author = "Khairnar, \{Pankaj V.\} and Lung, \{Tsai Hui\} and Lin, \{Yi Jung\} and Wu, \{Chi Yi\} and Koppolu, \{Srinivasa Rao\} and Athukuri Edukondalu and Praneeth Karanam and Wenwei Lin",

note = "Publisher Copyright: {\textcopyright} 2019 American Chemical Society.",

year = "2019",

month = jun,

day = "7",

doi = "10.1021/acs.orglett.9b01395",

language = "English",

volume = "21",

pages = "4219--4223",

journal = "Organic Letters",

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publisher = "American Chemical Society",

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T1 - An Intramolecular Wittig Approach toward Heteroarenes

T2 - Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes

AU - Khairnar, Pankaj V.

AU - Lung, Tsai Hui

AU - Lin, Yi Jung

AU - Wu, Chi Yi

AU - Koppolu, Srinivasa Rao

AU - Edukondalu, Athukuri

AU - Karanam, Praneeth

AU - Lin, Wenwei

PY - 2019/6/7

Y1 - 2019/6/7

N2 - 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.

AB - 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.

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UR - https://www.scopus.com/pages/publications/85067025370#tab=citedBy

U2 - 10.1021/acs.orglett.9b01395

DO - 10.1021/acs.orglett.9b01395

M3 - Article

C2 - 31117709

AN - SCOPUS:85067025370

SN - 1523-7060

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EP - 4223

JO - Organic Letters

JF - Organic Letters

IS - 11

ER -

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

Abstract

ASJC Scopus subject areas

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CCDC 1588093: Experimental Crystal Structure Determination

CCDC 1893512: Experimental Crystal Structure Determination

CCDC 1588092: Experimental Crystal Structure Determination

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

Abstract

ASJC Scopus subject areas

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Datasets

CCDC 1588093: Experimental Crystal Structure Determination

CCDC 1893512: Experimental Crystal Structure Determination

CCDC 1588092: Experimental Crystal Structure Determination

Cite this