Enantioselective Synthesis of 5-Trifluoromethyl-2-isoxazolines and Their N-Oxides by [Hydroxy(tosyloxy)iodo]benzene-Mediated Oxidative N–O Coupling

Biologically attractive trifluoromethyl-2-isoxazoline N-oxides were synthesized in good yields for the first time by the [hydroxy(tosyloxy)iodo]benzene-mediated oxidative N–O coupling of β-trifluoromethyl β-hydroxy ketoximes generated from trifluoromethyl β-keto alcohols. The present method allows the synthesis of previously unknown 5-trifluoromethyl-2-isoxazoline N-oxides and also provides an alternative for the enantioselective synthesis of antiparasitic 5-trifluoromethyl-2-isoxazolines by sequential reduction.