Cu-catalyzed [2 + 2 + 1] cascade annulation of vinyl iodonium salts with elemental sulfur/selenium for the modular synthesis of thiophenes and selenophenes

The Cu-catalyzed [2 + 2 + 1] regioselective synthesis of thiophenes/selenophenes was realized from aryl-vinyl iodonium salts and elemental sulfur/selenium.