A copper-catalyzed asymmetric Friedel-Crafts hydroxyalkylation of pyrazole-4,5-diones with 5-aminoisoxazoles

An asymmetric Friedel-Crafts hydroxyalkylation reaction of 5-aminoisoxazoles with pyrazole-4,5-diones was developed under the catalysis of 5% chiral copper complexes. This reaction exhibits functional group tolerance and excellent enantioselectivity. Moreover, the reaction can be scaled up and its mechanism was studied. An asymmetric Friede-Crafts hydroxyalkylation reaction was developed under the catalysis of chiral copper complexes. A variety of pyrazolone derivatives were obtained with excellent yields and enantioselectivities.