Electro‐ and Mechanochemical C(sp ² )‐H Chalcogenations of 4‐Hydroxycoumarins/4‐Hydroxy‐ N ‐methylquinolin‐2‐one: A Dual Green Synthetic Approach

We report two distinct and complementary synthetic strategies—electrochemical and mechanochemical—for the preparation of diversely functionalized chalcogenated 4‐hydroxycoumarins/4‐hydroxy‐ N ‐methylquinolin‐2‐one. Each method provides a practical and straightforward route to biologically relevant sulfide‐ and selenide‐functionalized oxygen‐ and nitrogen‐containing heterocycles. The developed protocols offer multiple advantages, including mild and energy‐efficient reaction conditions, the elimination of transition‐metal catalysts, the use of external heating and additional oxidants, short reaction times, high to excellent yields, a broad substrate scope, gram‐scale applicability, operational simplicity, and environmentally friendly execution. Additionally, the synthetic application of the synthesized compounds has been extended.