One-Step Synthesis of 2-Arylquinolin-4(1<i>H</i>)-Ones from 1-(2-Aminoaryl)-3-Arylpropan-1-Ones via Pd(II)-Catalyzed Dehydrogenative Cyclization

In this study, we developed palladium-catalyzed dehydrogenative cyclization to transform 1-(2-aminoaryl)-3-arylpropan-1-ones into 2-arylquinolin-4(1<i>H</i>)-ones, also known as aza-flavones which are the bioisosteres of flavones, in an atom-economic manner. This method exhibited excellent chemical compatibility with a broad substrate scope, accommodating up to 25 derivatives. Additionally, kinetic studies were performed to elucidate the reaction mechanism. Further, 2-phenylquinolin-4(1<i>H</i>)-one was used as a common intermediate for synthesizing privileged structures such as 4-methoxyquinoline, <i>N</i>-methylquinoline-4(1<i>H</i>)-one, and 4-(pseudo)halogenated quinoline moieties.