Synthesis, Crystal Structures and Antioxidant Activities of 1,5-Diketone Derivatives

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,1H NMR and 13C NMR,and the single crystal structure of compound 4 f was determined to be of triclinic system,space group P1 with a=8.6515(8),b=8.6694(10),c=12.4985(8)?,b=102.152(6)°,V=895.43(15)?3,Dc=1.625 g/cm3,Z=2,F(000)=436,m(MoKα)=1.807 mm-1,R=0.0342 and w R=0.0691.Furthermore,the result of antioxidation test demonstrated that compound 4 a 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.