Catalyst-Free Decarboxylative Couplings of Zinc Polyfluorobenzoates with Thiosulfonates for Accessing Polyfluoroaryl Sulfides

An efficient and environmentally friendly decarboxylative thiolation of zinc polyfluorobenzoates with odorless, nontoxic, and bench-stable thiosulfonates under catalyst-, ligand-, and additive-free conditions was realized. The uncatalyzed thioetherifications proceeded effectively via CO₂ extrusion in DMA, leading to a wide variety of polyfluoroaryl sulfides in moderate to good yields with broad functional group compatibility. In addition, scale-up synthesis and late-stage modification of bioactive complex molecules could be achieved, as well. Notably, a step-economical one-pot protocol with the straightforward utilization of polyfluorobenzoic acids and Zn(OH)₂ as precursors for in situ formation of zinc polyfluorobenzoates could also be successfully accomplished. Moreover, control experiments indicated that zinc polyfluorobenzoate was a more effective polyfluoroarylating agent in the current decarboxylative thioetherification when compared to its magnesium, potassium, and sodium counterparts.