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.