Comprehensive Summary The pentafluorosulfanyl (SF 5 ) moiety has garnered significant attention as a fluorinated functional group in the fields of medicinal chemistry, agrochemistry, and materials science, attributable to its distinctive physicochemical properties. In comparison to its structural analogue, trifluoromethyl, the SF 5 group demonstrates notably increased lipophilicity and pronounced electron‐withdrawing capacity. However, the direct pentafluorosulfanylation of unactivated alkenes remains challenging due to the intrinsic propensity of SF 5 Cl to undergo spontaneous chloropentafluorosulfanylation. Herein, we report a photoinduced radical pentafluorosulfanylation‐cyclization of alkenes enabled by an in situ substrate‐derived radical moderator strategy. Upon irradiation with LEDs, homolytic cleavage of the S–Cl bond in SF 5 Cl affords an electrophilic SF 5 radical, which undergoes addition to the alkene unit of the sulfinamide substrate, thereby generating a carbon‐centered radical intermediate. Subsequent intramolecular S H i cyclization yields the cyclic sulfinamide product, while a tert ‐butyl radical partakes in an XAT process with SF 5 Cl to regenerate the SF 5 radical and perpetuate the radical chain mechanism. Intriguingly, intramolecular hydrogen‐bonding interactions between the sulfinyl group and the CH 2 SF 5 moiety are posited to be responsible for the exceptional stereocontrol observed. Furthermore, the resulting SF 5 ‐containing motifs are readily amenable to further functionalization, thereby highlighting the broad synthetic utility and potential applications of these cyclic sulfinamides in pharmaceutical and materials science research.
Li et al. (Fri,) studied this question.