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-]isoquinolin-6(5)-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.

Synthesis of Sulfone Methylene-Substituted Indolines by Radical Cascade Cyclization of 2-Alkynylaniline Derivatives.

A radical cascade cyclization of 2-alkynylaniline derivatives with sulfonyl chlorides was developed to construct C3-sulfone methylene-substituted indolines in yields of 21 to 85% with a broad substrate scope under metal- and base-free conditions. This protocol could simultaneously build three new chemical bonds and employ a solvent-radical relay strategy, providing a rapid and concise approach toward an indoline framework. Scale-up reactions of this method and further transformations to afford useful indolines were also demonstrated.

Synthesis of Difluoroarymethyl-Substituted Benzimidazo[2,1-]isoquinolin-6(5)-ones under Mild Conditions.

A highly efficient method for synthesis of difluoroarymethyl-substituted benzimidazo[2,1-]isoquinolin-6(5)-ones using 2-arylbenzoimidazoles with α,α-difluorophenylacetic acid as reaction substrates has been developed through radical cascade cyclization. The advantage of this strategy lies in excellent functional group tolerance to generate the corresponding products in good yields under base- and metal-free conditions.