Hypervalent iodine-mediated one-pot synthesis of C3,6-dithioquinolin-2-ones†

Abstract

This study presents a transition-metal-free one-pot synthetic strategy for the efficient construction of C3,6-dithioquinolin-2-ones, which employs N-substituted tetrahydroquinolines and disulfides in a direct reaction, utilizing 2-iodoxybenzoic acid (IBX) as the oxidant and water as co-solvent to achieve regioselective oxidative desulfurization and functionalization of quinoline C–H bonds under mild conditions. In contrast to conventional approaches, this protocol eliminates the need for transition-metal catalysts (e.g., Pd, Ru) and directing groups, significantly reducing environmental risks associated with toxic reagents and lowering synthesis costs, and demonstrates high atom and step economy. Furthermore, the mixed solvent system (DCE/H₂O) reduces organic solvent consumption, while maintaining a broad substrate scope. Derivatization experiments confirm the straightforward conversion of products into functional molecules, offering a sustainable pathway for synthesizing complex heterocycles and providing a powerful means to expand diverse synthetic routes.