Visible-Light-Mediated Three-Component Decarboxylative Coupling Reactions for the Synthesis of 4-Alkylpyridines.

4-Alkylation of pyridines has been achieved by a photocatalyzed three-component reaction of an olefin, an aryloxyacetic acid, and cyanopyridine using Ir[dF(CF)ppy](dtbbpy)PF as a photocatalyst. In this way, a new type of 4-alkylpyridines bearing aryl and aryloxy substituents on the phenyl was accessed with potential pharmaceutical value. In addition to mild reaction conditions, the method has several other advantages, including a multicomponent one-pot protocol, good functional group tolerance, and easy amplification of the reaction scale. The reaction mechanism has been clarified by control experiments and computation of the reaction energy profile.