Visible Light‐Induced the Radical Cascade Cyclization of 2‐Isocyanobiaryls via 1,2‐Hydrogen Atom Transfer

Phenanthridines, as important structural moieties of many naturally occurring products, pharmaceuticals, and functionalized polycyclic heteroarenes, have attracted considerable attention among chemists due to their significant potential in pharmaceutical and material chemistry. The hydrogen atom transfer (HAT) process provides an important strategy for selective CH functionalization. However, net 1,2‐HAT processes have been reported and applied infrequently compared to the popularity of 1,5‐HAT processes. Herein, a visible light‐induced radical cascade cyclization of 2‐isocyanobiaryls via 1,2‐HAT is described to rapidly synthesize phenanthridines under mild conditions. This approach represents an example of radical cascade cyclization of 2‐isocyanobiaryls via infrequent 1,2‐HAT to access the phenanthridine core. This protocol features a 1,2‐HAT, a radical cascade process, broad substrate scope, and good functional group compatibility under mild and oxidant‐free reaction conditions.