Synthesis of Polycyclic Amines through Mild Metal‐Free Tandem Cross‐Dehydrogenative Coupling/Intramolecular Hydroarylation of <i>N</i>‐Aryltetrahydroisoquinolines and Crotonaldehyde

Abstract

Abstract A [4+2] cycloaddition reaction proceeding through tandem cross‐dehydrogenative coupling/intramolecular hydroarylation between N ‐aryltetrahydroisoquinolines and crotonaldehyde was developed by virtue of enamine–iminium catalysis, which enabled the rapid construction of ring‐fused tetrahydroquinolines. The first metal‐free catalytic oxidative coupling of γ‐selective C(sp 3 )–H bonds of crotonaldehyde was realized by using a secondary amine catalyst and 2,3‐dichloro‐5,6‐dicyanoquinone.