Metal-Free Temperature-Controlled Intermolecular [3 + 2] Annulation to Access Benzo[ d ]thiazole-2(3 H )-thiones and Benzo[ d ]thiazol-2(3 H )-ones.

A facile access to benzo[ d ]thiazole-2(3 H )-thiones and benzo[ d ]thiazol-2(3 H )-ones has been developed through a temperature-controlled intermolecular [3 + 2] annulation of N,N-disubstituted arylhydrazines with CS 2 in the presence of DMSO. This protocol can obviate the prefunctionalization of the starting materials. This direct C-S/C-N bond formation reaction was performed in the absence of any external catalysts, transition metals, bases, ligands, and oxidants with high step economy.