with urea–hydrogen peroxide using iron(III) and manganese (III)- tetraphenylporphyrins [Fe(TPP)Cl], [Mn(TPP)Cl] and manganese (III)-octabromotetraphenyl porphyrin [Mn(TPPBr8)Cl] as catalysts. Experimental results showed the released urea from UHP acts as an axial ligand. These catalysts showed high selectivity in oxidation of imines to corresponding nitrones and oxaziridines at 0°C to room temperature
Using hydrogen peroxide as a key oxidant, catalytic oxidativeamidation between aldehydes and amines was effectively carried out with PdCl2–xantophos as a catalyst in methanol under acidic conditions. The new protocol is mechanistically different from the previous one through β-hydride elimination.