Visible-Light-Promoted Xanthate-Transfer Cyclization Reactions of Unactivated Olefins under Photocatalyst- and Additive-Free Conditions.

A general visible-light-induced photocatalyst-/additive-free strategy was developed for the construction of various nitrogen-heterocycles (42 examples, up to 97% yield) such as γ-lactams, δ-lactams, pyrrolidines, indolones, quinolinones, and fused polycyclic structures at room temperature. The prominent features of this protocol are mild and environmentally friendly conditions, broad substrate scope, and good functional group tolerance. Importantly, the reaction can be performed under natural sunlight, the most sustainable energy source imaginable. Furthermore, this strategy provides straightforward access to a range of derivatives through subsequent elaboration of the xanthate group.