Diastereoselective Heterocyclization of Geminal Bromo-fluoro Arylcyclopropanes by Nitrosonium Tetrafluoroborate: Access to 4-fluorinated Isoxazolines and Isoxazoles
2-Aryl-1-bromo-1-fluorocyclopropanes, Nitrosonium tetrafluoroborate, 5-Aryl-4-bromo-4-fluoroisoxazolines, 5-Aryl-4-fluoroisoxazoles
College of Natual Science and Mathematics, Chemistry and Biochemistry
A series of 5-aryl-4-bromo-4-fluoroisoxazolines was synthesized via nitrosation of 2-aryl-1-bromo-1-fluorocyclopropanes with NOBF4. It was shown that the E-isomers of the cyclopropanes react highly regio- and diastereoselectively leading exclusively to the E-isomers of the isoxazolines. The obtained 5-aryl-4-bromo-4-fluoroisoxazolines were transformed selectively into the corresponding 5-aryl-4-fluoro- or 5-aryl-4-bromoisoxazoles in good yields in the reaction with Lewis acids.
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Bondarenko, O. B., Komarov, A. I., Karetnikov, G. L., Nikolaeva, S. N., Zyk, N. V., Holt, T., & Kutateladze, A. G. (2019). Diastereoselective heterocyclization of geminal bromo-fluoro arylcyclopropanes by nitrosonium tetrafluoroborate: Access to 4-fluorinated isoxazolines and isoxazoles. Tetrahedron, 75(46), 130666. DOI: 10.1016/j.tet.2019.130666.