I₂/O₂-Enabled N-S Bond Formation to Access Functionalized 1,2,3-Thiadiazoles

A new, metal-free intermolecular formal [3 + 2] heterocyclization between triethylammonium thiolates and aryl hydrazines has been established by using the combination of I₂ and O₂ as efficient oxidation sources, allowing a concise and low-cost access to new densely functionalized 1,2,3-thiadiazoles with good to excellent yields. The reaction showed a broad scope of substrates of both reactants and attractive characteristics consisting of eco-friendly oxidants, flexible structural modification, broad functional group compatibility, and mild reaction conditions.