amine–thioureas are effective catalysts for the first diastereo- and enantioselectiveepoxidation of unsaturated pyrazolones. The trans- or cis-spiroepoxides are preferentially obtained in good yield and high to excellent enantioselectivityusing an appropriate organocatalyst and tert-butyl hydroperoxide as the oxidant. The epoxidation appears applicable to highly challenging β,β′-substituted unsaturated