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.