On-Demand Continuous Flow Synthesis of Pentafluorosulfanyl Chloride (SF₅Cl) Using a Custom-Made Stirring Packed-Bed...

The pentafluorosulfanyl (SF₅-) group has been the subject of a surge of interest in the past decade, but there is still little practicality associated with its synthesis and installation. Herein is reported the first continuous flow synthesis of pentafluorosulfanyl chloride (SF₅Cl), the most common reagent for the synthesis of SF₅-substituted compounds. The synthesis is based on inexpensive and easy-to-handle reagents: sulfur powder (S₈), trichloroisocyanuric acid (TCCA) and potassium fluoride (KF). To this end, a custom-made stirring reactor was designed to allow for fast, safe, and highly efficient on-demand synthesis of SF₅Cl. The resulting SF₅Cl solution is showcased in the radical addition on alkynes in a telescoped fashion.