Radical Alkylation of Imines with 4-Alkyl-1,4-dihydropyridines Enabled by Photoredox/Brønsted Acid Cocatalysis.

Radical alkylation of imines with 4-alkyl-1,4-dihydropyridines cocatalyzed by iridium/ruthenium complex and Brønsted acid under visible light irradiation has been achieved. Both aldimines and ketimines can undergo this transformation. Common functional groups, such as hydroxyl groups, ester, amide, ether, cyanide, and heterocycles, can be tolerated in this reaction. A variety of structurally diverse amines (57 examples) have been produced with up to 98% isolated yields using this method.