Photoredox-Catalyzed Decarboxylative Coupling of 2-Quinolinones with α-Amino Acids

The dihydroquinolin-2-one scaffold is a privileged structure in many bioactive compounds. We describe a visible-light-driven photoredox catalysis strategy for the decarboxylative coupling of 2-quinolinones with α-amino acids, enabling the efficient synthesis of 3-aminoalkyl dihydroquinolin-2-ones. This method utilizes readily available α-amino acids to generate α-aminoalkyl radicals under mild conditions. It exhibits a broad substrate scope, accommodating natural α-amino acids (both cyclic and acyclic), other α-heteroatom-substituted acids, and aliphatic carboxylic acids. This redox-neutral transformation proceeds under simple conditions with good functional group tolerance, eliminates the need for sacrificial reagents or hydrogen atom donors, and exhibits good step economy. Decarboxylation generates CO₂ as the only byproduct.