Electrochemical Synthesis of Phosphorothiolated Isocoumarins and Benzothiophenes

A new electrochemically driven radical annulation of o ‐alkynylbenzoates and o ‐alkynylthioanisoles with S ‐hydrogen phosphorothioates has been developed, offering an environmentally friendly and atom‐efficient approach to synthesize structurally diverse phosphorothiolated isocoumarins and benzothiophenes. Compared with previous methods, this transformation uses electrons as traceless reagents to oxidize S‐hydrogen phosphorothioates, circumventing the need for stoichiometric initiators and avoiding the formation of equivalent waste. Acetone is employed as a sustainable solvent, and green methanol is produced as the sole by‐product, further highlighting its sustainability. Moreover, the high efficiency and broad substrate scope are demonstrated by 47 total examples and up to 85% yield.