A new transition-metal-free protocol for the synthesis of polysubstituted 1,5-diketone derivatives from readily available starting materials has been developed.All the compounds were confirmed by HRMS,tH NMR and 13C NMR,and the single crystal structure of compound 4f was determined to be of triclinic system,space group P(1) with a =8.6515(8),b =8.6694(10),c =12.4985(8) (A),β =102.152(6)°,V=895.43(15) (A)3,Dc =1.625 g/cm3,Z =2,F(000) =436,μ(MoKa) =1.807 mm-1,R =0.0342 and wR =0.0691.Furthermore,the result ofantioxidation test demonstrated that compound 4a exhibited better antioxidant activity than butylated hydroxytoluene and vitamin C by the ABTS+ radical cation decolorization assay.In addition,we further studied the mechanism of the transition-metal-free catalytic multicomponent domino reaction.