P–C bond formation via direct and three-component conjugate addition catalyzed by ZnO nano-rods for the synthesis of 2-oxindolin-3-yl-phosphonates under solvent-free conditions

Abstract

A simple and novel method is reported for the synthesis of 2-oxindolin-3-yl-phosphonates using ZnO nano-rods as a catalyst under solvent-free conditions at room temperature. ZnO nano-rods are synthesized successfully by employing Zn(OAc)₂·2H₂O, NH₃ and polyethylene glycol (PEG , M_w = 2000). X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and BET surface measurement were used to characterize the structure and morphology of the catalyst.