Palladium and copper complexes with oxygen–nitrogen mixed donors as efficient catalysts for the Heck reaction

A simple bidentate ligand, 2-(2′-hydroxyphenyl)-5,6-dihydro-1,3-oxazine, was readily prepared with a two-step synthesis. Two novel complexes of Pd(II) and Cu(II) with this (N,O) oxazine ligand have been prepared and the molecular structures of these complexes have been confirmed by X-ray structure analysis, NMR, IR and UV–Vis spectroscopy. These complexes efficiently catalyze the Heck reaction of aryl halides with olefins at 120 °C in 8 h. The reaction conditions for the Heck coupling of iodobenzene with styrene was optimized by varying the amount of the catalyst, reaction temperature, solvent and exogenous base.