Electromagnetic Milling-Promoted Steel Rods-enabled Sonogashira Coupling Reactions of Aryl halides and Terminal alkynes

Abstract

Nickel-catalyzed Sonogashira reactions between aryl halides and terminal alkynes have become a powerful method for constructing C(sp²)–C(sp) bonds. Conventional approaches typically required copper co-catalysts, solvents, inert atmospheres, and external heating. Herein, we report an alternative and streamlined reductive C(sp²)–C(sp) cross-coupling protocol that employs inexpensive steel rods as a nickel catalyst source, eliminating the need for expensive Ni/Cu dual catalysts. This electromagnetic milling (EMM) promoted strategy effectively circumvents the constraints associated with traditional nickel-catalyzed Sonogashira reactions. Mechanistic studies reveal that alloyed Ni⁰ within the steel rods functions as the active catalyst, and EMM plays a critical role in promoting alkyne transfer to Niᴵᴵ species.