Short step synthesis of natural 2-arylquinolones based on iridium-catalyzed three-component coupling quinoline synthesis

Eduline (la), graveoline (1b), and 6-methoxy-2-(4-methoxyphenyl)-1-methylquinolone (1c) were synthesized by iridium-catalyzed three-component coupling reaction. Reaction of an aniline, an aromatic aldehyde, and acetaldehyde gave the corresponding substituted quinoline. Using 1,1-dimethoxyethane instead of acetaldehyde, the three component coupling reactions were also carried out to give the quinolines in higher yields. N-Methylation of the quinolines with methyl trifrate followed by oxidation with potassium ferricianate gave the quinolones.