Visible-Light-Promoted Manganese-Catalyzed Atom Transfer Radical Cyclization of Unactivated Alkyl Iodides.

An expedient visible-light-promoted atom transfer radical cyclization (ATRC) reaction of unactivated alkyl iodides facilitated by earth-abundant and inexpensive manganese catalysis is described. The practical protocol shows a broad substrate scope and good functional-group tolerance, allowing for the preparation of synthetically valuable alkenyl iodides and diquinanes under simple and mild reaction conditions. Notably, the method provides a net redox-neutral strategy for ATRC reactions that avoids classic hydrogen atom transfer mechanism.