Theoretical Study on Photo‐induced Copper Autoredox Construction of Chiral Amines

Abstract

Density functional theory (DFT) calculations were conducted to investigate the photo‐induced copper‐catalyzed C‐N coupling reaction for the synthesis of chiral tertiary amines. The ligands' effects on the metal center and the factors determining regioselectivity in chiral tertiary amine formation were examined. The computational results revealed that the oxidative quenching process involved in the photocatalytic redox cycle via Cu I‐Cu I*‐Cu II‐Cu III transitions. Throughout the reaction, four key processes occurred: C‐Br bond activation, ligand exchange, amide ion/Br ion exchange, and C‐N coupling. Among these steps, alkyl radical generation through single electron transfer was identified as the rate‐determining step with an energy barrier of 13.9 kcal/mol. The chelating diphosphine ligand improved copper's reducibility and its capacity to activate the C‐Br bond by charge transfer when exposed to visible light (CT). Copper's own redox process was facilitated by interactions between diphosphine and diamine ligands. Finally, when combined with oxygen, this catalyst system formed a chiral plane Cu II‐O 1‐N 1‐N 2‐N 3 essential for enantioselective product formation.