Straightforward Synthesis of Quinoline Sulfonamides via Aminosulfonylation Using a Bench-Stable SO₂ Surrogate

In this study, we utilize inexpensive, bench-stable, and nontoxic K₂S₂O₅ as a surrogate for SO₂ in a palladium-catalyzed one-pot, two-step synthesis of quinoline sulfonamides. The protocol exhibits broad substrate tolerance, accommodating a wide range of amines and substituted quinolines, affording sulfonamides in 25-92%. We obtained mechanistic insights through time-dependent reaction monitoring and control experiments. The methodology was successfully extended to synthesizing an antiproliferative analogue and the one-pot diaminosulfonylation of 3,6-diiodoquinoline, demonstrating its versatility and scalability.