Visible-light-promoted Meerwein 3,4-diarylation of maleimides with electron-deficient diazonium salts

3,4-Diarylmaleimides are widely explored as structural fragments of natural products, bioactive substances and components of luminescent materials. The reaction of aryl diazonium salts with various maleimides under visible light irradiation was studied. It was found, that aryl diazonium salts with electron withdrawing substituents give 3,4-diarylmaleimides under visible light irradiation at room temperature in the presence of sodium trifluoroacetate under photocatalyst and transition -metal -free conditions in yields up to 54%.