Visible-Light-Induced CdSeS/CdZnSe/ZnSe/ZnS Quantum-Dot-Catalyzed Three-Component Reaction for the Synthesis of α-(4-Pyridyl)benzylaniline Derivatives

Using recyclable CdSeS/CdZnSe/ZnSe/ZnS core/shell quantum dots (QDs) as a photocatalyst under visible light irradiation, the synthesis of α-(4-pyridyl)benzylaniline derivatives was achieved through a three-component reaction. These reactions offer advantages such as low catalyst loading, wide substrate scope, high yield, mild reaction conditions, and easy scalability. They have been successfully applied for the derivatization of natural amino acids and pharmaceutical late-stage structural modification. Importantly, this core/shell QD exhibits a remarkably high turnover number (TON) of 2.27 × 10⁵ and can be easily recovered and recycled in the reaction for more than 5 times without significant loss of catalytic activity. Mechanistic studies reveal that thiols/thiophenols in the reaction serve as proton donors, facilitating the reduction of cyanopyridine and the <i>in situ</i> form of imine.