Thiosemicarbazone Salicylaldiminato-Palladium(II)-Catalyzed Mizoroki-Heck Reactions

Four tridentate thiosemicarbazone salicylaldiminato-palladium(l I) complexes of the general formula [Pd(saltsc-R)PPh3] [saltsc = salicylaldehyde thiosemicarbazone; R=H (1), 3-tert-butyl (2), 3-methoxy (3), 5-chloro (4)], have been evaluated as catalyst precursors for the Mizoroki-Heck coupling reaction between a variety of electron-rich and electron-poor aryl halides and olefins. The palladium complexes (0.1-1 mol% loading) were found to effectively catalyze these reactions with high yields being obtained when aryl iodides and aryl bromides were utilized. The effects of base, catalyst loading, reaction temperature and reaction time on the catalytic activity of the most active complex were also investigated.