Mechanoredox radical annulation for the solvent-free synthesis of 2-substituted benzothiophenes

https://doi.org/10.1039/d6mr00013d

A mechanoredox-enabled radical annulation under ball-milling conditions affords 2-substituted benzothiophenes 3 from 2-(methylthio)benzenediazonium salts 1 and alkynes 2. Mechanical energy drives single-electron transfer without photoredox or electrochemical systems, providing a practical and environmentally benign approach to heterocycle synthesis.