Visible-Light-Induced Intramolecular Radical Cyclization\nfor the Synthesis of Benzimidazo-isoquinolineones and Pyrrolidones

A visible-light-induced\nradical cyclization of α-brominated\namides has been developed to construct benzimidazole[2,1-<i>a</i>]isoquinolin-6(5<i>H</i>)-ones and pyrrolidonesin in yields\nup to 97%. The methodology exhibits a certain functional-group compatibility\nwith 43 examples and operational simplicity, offering a rapid and\nconcise approach to obtain five- and six-membered rings under the\nirradiation of 18 W blue LED. Additionally, large-scale reaction of\nthis method for synthesizing benzimidazo-isoquinolineones and the\nfurther transformations to useful pyrrolidones were also conducted\nand afforded positive results.