Substrate-induced Selective -C(sp³)-H Activation of N-alkyl Amines: Synthesis of Coumarin-fused Quinolinones under Air

A substrate-induced synthesis of coumarin-fused quinolinones is achieved from 4-(phenylamino)-2H-chromen-2-ones using N-alkyl amines as the solvent and a carbon source under air conditions without any catalysts in one pot. This protocol highlights the special roles of 4-(phenylamino)-2H-chromen-2-ones which were not only used as reactants but also as an internal oxidant selectively activated N-alpha-C(sp(3))-H bond. This reaction features catalyst-free, broad substrate scopes (N-alkyl amines 27 examples and quinolinones 24 examples), operationally simple for the one-step synthesis, and recovery and recycling of the solvent.