Expanding Radical Chloropentafluorosulfanylation of Alkynes.

The chloropentafluorosulfanylation of alkynes is a delicate but crucial operation for accessing SF5-alkynes that serve as substrates in numerous transformations. Dolbier's procedure using Et3B/O2 was the most efficient approach, while recent efforts make use of other initiators and light activation. We found that THF, as a single stimulus, is sufficient to trigger the reaction of SF5Cl with alkynes. We determined the configuration of Cl/SF5 products and clarified the structure of side-products.