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

Abstract

Abstract 2‐Aryl‐2,3‐dihydroquinolin‐4(1 H )‐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(1 H )‐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(1 H )‐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.