Oxidative Fluorination of Heteroatoms Enabled by Trichloroisocyanuric Acid and Potassium Fluoride

In synthetic method development, the most rewarding path is seldom a straight line. While our initial entry into pentafluorosulfanyl (SF(5)) chemistry did not go according to plan (due to inaccessibility of reagents such as SF(5)Cl at the time), a “detour” led us to establish mild and inexpensive oxidative fluorination conditions that made aryl‐SF(5) compound synthesis more accessible. The method involved the use of potassium fluoride and trichloroisocyanuric acid (TCICA)—a common swimming pool disinfectant—as opposed to previously employed reagents such as F(2), XeF(2), HF, and Cl(2). Thereafter, curiosity led us to explore applications of TCICA/KF as a more general approach to the synthesis of fluorinated Group 15, 16, and 17 heteroatoms in organic scaffolds; this, in turn, prompted SC‐XRD, VT‐NMR, computational, and physical organic studies. Ultimately, it was discovered that TCICA/KF can be used to synthesize SF(5)Cl, enabling SF(5) chemistry in an unexpected way.