Palladium-catalyzed Sonogashira coupling reaction followed by isomerization and cyclization

2-Iodoaniline reacts with terminal acetylenic carbinols in THF at 80 °C in the presence of a catalytic amount of PdCl2(PPh3)2 and CuI along with aqueous tetrabutylammonium hydroxide to afford the corresponding 2-arylquinolines in good yields. The catalytic pathway seems to be proceeded via a sequence involving initial Sonogashira coupling between 2-iodoaniline and terminal acetylenic carbinols to form coupled acetylenic carbinols, isomerization of coupled acetylenic carbinols to α,β-unsaturated ketones, and cyclodehydration.

Graphical abstract2-Iodoaniline undergoes tandem Sonogashira coupling, isomerization and cyclodehydration with terminal acetylenic carbinols in the presence of PdCl2(PPh3)2 and CuI along with aqueous tetrabutylammonium hydroxide in THF to afford 2-arylquinolines in good yields. The present reaction is a convenient one-pot synthetic route for 2-arylquinolines from 2-iodoaniline and terminal acetylenic carbinols.Figure optionsDownload full-size imageDownload as PowerPoint slide