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

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