A photosensitized metal free approach to α-ketoamides: sequential oxidative amidationdiketonization of terminal alkynes

摘要

A novel transition metal-free photosensitized protocol has been developed for the synthesis of α-ketoamides via oxidative coupling of alkynes and amines in the presence of thiophenol under visible light irradiation and rose bengal dye. A series of alkynes with both electron-donating and electron-withdrawing groups were successfully employed for the synthesis of their corresponding α-ketoamides. This reaction presents a benign visible light based milder synthetic methodology with broad functional-group tolerance.