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*
*Department of Chemistry, National Taiwan Normal University, 88, Sec. 4, Tingchow Road, Taipei 11677, Taiwan R.O.C., Email: wenweilinntnu.edu.tw
P. V. Khairnar, T.-H. Lung, Y.-J. Lin, C.-Y. Wu, S. R. Koppolu, A. Edukondalu, P. Karanam, W. Lin, Org. Lett., 2019, 21, 4219-4223.
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α-Halohydrazones/ketoximes are transformed into trisubstituted pyrazoles/disubstituted isoxazoles by treatment with phosphine, acyl chloride, and a base. Proper functionalization of α-haloketoximes and a change of conditions also allowed the chemoselective synthesis of chromenone-oximes as well as rearranged isoxazoles.
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