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

The pentafluorosulfanyl (SF-) 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 (SFCl), the most common reagent for the synthesis of SF-substituted compounds. The synthesis is based on inexpensive and easy-to-handle reagents: sulfur powder (S), trichloroisocyanuric acid (TCCA) and potassium fluoride (KF).

1,3-Dipolar Cycloaddition of SF-Alkynes with Nonstabilized Diazo: Synthesis of Highly Substituted SF-3-Pyrazoles.

This work presents the 1,3-dipolar cycloaddition of SF-alkynes with nonstabilized diazo compounds under mild conditions, producing highly substituted SF-3-pyrazoles. Eighteen examples are given, with yields of up to 91%. The two regioisomers were obtained in ratios ranging from 27:73 to 73:27.

Rhodium-Catalyzed Intramolecular Cyclopropanation of Trifluoromethyl- and Pentafluorosulfanyl-Substituted Allylic Cyanodiazoacetates.

The synthesis of trifluoromethyl (CF)- and pentafluorosulfanyl (SF)-substituted cyclopropane-fused γ-lactones was carried out through Rh(esp)-catalyzed intramolecular cyclopropanation in up to 99% yields. Twelve examples of this interesting scaffold are reported, as well as postfunctionalizations that provide access to highly functionalized CF- and SF-substituted cyclopropanes. These novel SF-substituted analogues join the very short list of available pentafluorosulfanyl intermediates.