Light promoted metal-free regio- and stereoselective isoperfluoropropylation of unactivated alkenes with an i-C₃F₇-iodine(iii) reagent

The isoperfluoropropyl group (i-C3F7) is a large analogue of the classical CF3 group, featuring more steric hindrance and a stronger electron-withdrawing effect, and is normally considered as a "super" CF3 group and plays an irreplaceable role in pharmaceuticals and agrochemicals. Herein, a visible-light promoted metal-free regio- and stereoselective isoperfluoropropylation of various terminal alkenes and alkynes with an i-C3F7-iodine(III) (PFPI) reagent has been developed. Benefitting from the operational simplicity of the procedure and broad substrate applicability, this strategy provides a general and green way for the synthesis of various perfluoroalkylated products without the use of any metal catalysts. Detailed mechanistic experiments revealed a SET-induced concerted mechanistic pathway in the photoredox reactions and demonstrated for the first time that Ritter-type cations can undergo intramolecular elimination to generate alkenes.