Photocatalytic Styrene [4 + 2] Cycloaddition/Decyanative Pyridylation Cascade for the Synthesis of 4-(Tetralyn-1-yl)pyridines.

We herein report a visible-light-driven multicomponent cascade reaction that integrates [4 + 2] cycloaddition with radical-radical coupling in a single step, enabling facile and rapid synthesis of structurally diverse cyanopyridines. This atom-economical protocol proceeds under mild conditions with broad functional group tolerance and is readily scalable to gram quantities, delivering drug-like scaffolds directly from simple arylethylenes. By obviation of the need for pre-assembled cyclic precursors, this strategy streamlines the fused-ring construction via radical annulation and establishes a powerful platform for C-4 functionalization of pyridines.