Regiodivergent ZnO-NP-Catalyzed Decarboxylative Synthesis of Substituted Quinolines and Application of N-Oxide via Late-Stage Diversification

Abstract An efficient regiodivergent ZnO-NP catalyzed decarboxylative protocol for the direct synthesis of 3-arylquinolines and 2,3-diarylquinolines with readily available cinnamic acids and arylazides via C-H functionalization and C-C/C-N bond formation has been developed. In this work, the regioselectivity can be rationally tuned via the perfect choice of reaction solvents; 3-substituted quinolines were obtained when ethylene glycol was used as the solvent, whereas the use of AcOH as solvent afforded 2,3-disubstituted quinolines. The reaction is simple, gram-scale synthesis, environmentally friendly, and proceeds under very mild conditions with a range of functionalities in good to excellent yields. Furthermore, this strategy’s synthetic utility provided a practical approach for the C-H activation of 3-substituted quinoline via N-oxide through the C-C, C-O, C-S, and C-N bond formation and late-stage functionalization (LSF) of drug molecules and natural products were also performed.