Ionic-Liquid-Promoted Palladium-Catalyzed Multicomponent Cyclocarbonylation of <i>o</i>-Iodoanilines and Allenes To Form Methylene-2,3-dihydro-1<i>H</i>-quinolin-4-ones

Abstract

The palladium-catalyzed cyclocarbonylation reaction of o-iodoanilines with allenes and CO in 1-butyl-3-methylimidazolium hexafluorophosphate afforded 3-methylene-2,3-dihydro-1H-quinolin-4-ones in moderate to excellent yields under a low pressure (5 atm) of CO. The ionic liquid, as the solvent and promoter, enhances the efficiency of the cyclocarbonylation reaction. The recyclability of the system of ionic liquid/catalyst/ligand was also demonstrated.