Electrochemical reduction of sulfoxides to thioethers with hydrosilanes catalyzed by a recyclable ionic liquid

The first electrochemical reduction of sulfoxides to thioethers has been achieved using a recyclable ionic liquid as both catalyst and electrolyte, without metal catalysts, stoichiometric redox reagents, or external electrolytes. The ionic liquid showed no significant loss of catalytic activity over six cycles. Various sulfoxides (32 examples) were efficiently reduced to the corresponding thioethers in up to 98% yield using hydrosilanes as the activating agent. Notably, the protocol exhibits robust scalability under optimized conditions.