Pd-Catalyzed Domino Cross-Coupling: Synthesis of Functionalized 4-(Arylethynyl)Coumarins

A Pd-catalyzed domino cross-coupling methodology was developed to synthesize various 4-(arylethynyl)coumarin derivatives involving 4-(gem-dibromovinyl)coumarins and triarylbismuths as threefold aryl donor reagents. In these reactions, 4-(gem-dibromovinyl)coumarin derivatives have been cross-coupled with sub-stoichiometric amounts of triarylbismuth reagents. This study involving mono-, chemoselective and bis-couplings have been demonstrated with versatile reactivity under the established Pd-catalyzed domino coupling conditions affording good to high product yields.