Sulfuration‐Triggered Radical Cyclization of o‐Cyanoarylacrylamides to 3‐Thiomethylated Quinoline‐2,4‐dione

A radical cascade sulfuration/cyclization of o‐cyanoarylacrylamides with dicumyl peroxide as an oxidant and thiols as coupling partners has been developed. This reaction was conducted under simple conditions and showed wide substrate scope, affording the corresponding products in good chemical yields. This work provides a new and efficient strategy for the preparation of 3‐thiomethylated quinoline‐2,4‐diones. A DCP‐promoted radical cascade sulfuration/cyclization/hydrolysis reaction of o‐cyanoarylacrylamides with thiols as coupling partners under metal‐free conditions was developed, which afforded the corresponding 3‐thiomethylated quinoline‐2,4‐diones with good yields.