Visible-Light-Promoted Fe(III)-Catalyzed N-H Alkylation of Amides and N-Heterocycles.

The combination of the radical chemistry of ligand-to-metal charge transfer with metal catalysis by a single iron salt helps to realize the visible-light-promoted N-H alkylation of amides and N-heterocycles. A wide variety of amides and nitrogen-containing heterocycles were tolerated in our protocol to give N-alkylated products. The applicability of this protocol was further demonstrated by late-stage alkylation of N-H-containing pharmaceuticals. Moreover, N-H-alkylated α-amino tetrahydrofurans could be transformed into versatile ring-opened amino alcohols under reducing conditions. A mechanistic study revealed that hydrogen atom transfer by a tert-butoxyl radical and a chlorine radical was responsible for the activation of C(sp3)-H precursors.