Synthesis of 5‐Seleno‐Substituted Spirocyclopentapyridine‐2,5‐dien‐4‐ones and Benzoquinolines via Radical Cyclization of Arylethynylpyridines

A practical strategy for obtaining novel 5‐seleno‐substituted spirocyclopenta[b]pyridines‐2,5‐dien‐4‐ones and benzo[h]quinolines via radical cyclization is reported. The synthetic protocol explores the reaction between arylethynylpyridines and diorganyl diselenides in acetonitrile as solvent and Oxone® as oxidant at 82 °C. This easy‐to‐handle, eco‐friendly metal‐free approach was carried out under an open atmosphere, affording functionalized organoselenium compounds in good to excellent yields. Control experiments and scale‐up test were performed to demonstrate the efficiency of this methodology.