Metal‐free Cascade Radical Cyclization of N‐Methylacrylyl‐2‐phenylbenzimidazole: Construction of Aryldifluoromethylated Benzimidazole[2,1‐a]iso‐Quinoline‐6(5H)‐ketone

A facile and effective metal-free decarboxylative cyclization of N-methacryloyl-2-phenylbenzimidazole with arylthio (oxy) difluoroacetic acids or alpha,alpha-aryldifluoroacetic acids was proposed to prepare a series of aryldifluoromethylated benzimidazole[2,1-a]iso-quinoline-6(5H)-one derivatives in medium to good yields with good functional group tolerance, readily available raw materials and simple operation. In addition, experimental studies showed that the CF2 group of arylthiodifluoroacetic acids plays a crucial role in this conversion.