Visible-Light-Mediated Iodoperfluoroalkylation of Alkenes in Flow and Its Application to the Synthesis of a Key Fulvestrant Intermediate.

Two efficient continuous flow iodoperfluoroalkylation methods are described: using 0.05 mol % perylene diimide (PDI) photocatalyst under 450 nm irradiation or substoichiometric triethylamine under 405 nm irradiation. These methods enable dramatically elevated productivity versus batch processes. The triethylamine-mediated method is explored mechanistically and in substrate scope. The gram-scale synthesis of an active pharmaceutical ingredient side chain is also reported in flow, via a photochemical iodoperfluoroalkylation followed by hydrogenolysis.