A Novel Approach to N-Tf 2-Aryl-2,3-Dihydroquinolin-4(1H)-ones via a Ligand-Free Pd(II)-Catalyzed Oxidative Aza-Michael Cyclization

2-Aryl-2,3-dihydroquinolin-4(1H)-ones have recently been identified as important structures with potent biological activities such as antitumor and antidiabetic effect. Herein, a total of 25 novel N-Tf 2-aryl-2,3-dihydroquinolin-4(1H)-ones were expediently synthesized via the oxidative aza-Michael cyclization of N-Tf-2 '-aminodihydrochalcones by ligand-free palladium(II) catalysis. This study presents a new synthetic approach to yield N-Tf 2-aryl-2,3-dihydroquinolin-4(1H)-ones, which can be easily transformed into pharmacologically interesting aza-flavanones and other N-heterocycles, such as quinolines and tetrahydroquinolines, in yields up to 84 %. This methodology has various advantages, which includes short reaction times under mild conditions and suitable functional group tolerance. Furthermore, a plausible mechanism was proposed and demonstrated by kinetic analysis.

Automated summary

2-Aryl-2,3-dihydroquinolin-4(1H)-ones have been identified as important structures with potent biological activities. In this study, 25 novel N-Tf 2-aryl-2,3-dihydroquinolin-4(1H)-ones were efficiently synthesized via oxidative aza-Michael cyclization. This methodology offers advantages such as short reaction times and suitable functional group tolerance.