An asymmetric organocatalytic aza-Friedel-Crafts reaction was developed to give the enantioenriched Δ4-isoxazoline scaffold bearing a quaternary-substituted stereogenic centre in good-to-excellent yields and enantioselectivity (50–99%, 55–>99% ee). This protocol involves the in situ generated isoxazolium ions in the presence of a chiral phosphoric acid followed by the heteroarene addition through asymmetric counteranion-directed catalysis. (Figure presented.).
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