Enabling Fluoroalkyl-Sulfonylalkylation and Fluoroalkyl-Halogenation of Alkenes and Alkynes via Photoredox Catalysis

High Resolution Image Download MS PowerPoint Slide 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 SO 2 groups and alkyl bromides to intercept the ensuing sulfonyl intermediates in a process that creates one C(sp 3 )-C(sp 3 ) and two C(sp 3 )-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, SO 2 incorporation, and subsequent S N 2-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.