Redox-Neutral Photocatalytic Radical Cascade Cyclization for the Synthesis of CH2CN/CF2COOEt/CF3-Containing Benzo[4,5]imidazo[2,1-a]isoquinolin-6(5H)-One Derivatives

A novel method for the synthesis of benzo[4,5]imidazo[2,1-a]isoquinolin derivatives via visible-light-induced radical cascade cyclization is described. By using N-methacryloyl-2-phenylbenzoimidazoles and diverse radical precursors, various benzo[4,5]imidazo[2,1-a]isoquinolin derivatives containing CH2CN/CF2COOEt/CF3 can be formed in good to excellent yields under mild reaction conditions. This method exhibits good functional group tolerance and a wide range of substrate scope.