We describe a versatile photocatalytic approach for inter- and intramolecular fluoroalkyl-sulfonylalkylation of carbon-carbon bonds in activated and unactivated alkenes and alkynes. This protocol employs fluoroalkyl sulfinate salts as bifunctional reagents to introduce fluoroalkyl and SO2 groups and alkyl bromides to intercept the ensuing sulfonyl intermediates in a process that creates one C(sp3)-C(sp3) and two C(sp3)-S bonds in one step. This method is applicable for the fluoroalkyl-sulfonylalkylation of both alkenes and alkynes bearing a diverse set of functional groups and unsaturated gaseous hydrocarbons. The robustness of the method is also demonstrated by the late-stage diversification of steroids, alkaloids, and pharmaceuticals. Mechanistic insights reveal a photoredox-mediated sequential process involving fluoroalkyl radical addition, SO2 incorporation, and subsequent SN2-type displacement. Notably, the same reaction condition can be extended to achieve iodo- and bromo-trifluoromethylation via a halogen atom transfer mechanism by utilizing alkyl iodides and bromoacetyl bromides, respectively, in place of general alkyl bromides.
Inaththappulige et al. (Fri,) studied this question.