Immobilization of Acid-base cooperative catalyst on MCM-41 as a heterogeneous approach for asymmetric cyanoethoxycarbonylation of isatins
A novel, highly efficient and recyclable quinine thiourea based catalyst grafted on MCM-41 mesoporous silica was synthesized and explore as a heterogeneous catalyst for cyanoethoxycarbonylation of isatin. MCM-41 has a high specific surface area and pore volume which allow maximum catalytic centre to incorporate into pores. The catalyst was characterized by various sophisticated analytical technique viz X-ray powder diffraction (XRD), TEM, Thermogravimetric analysis (TGA), FTIR, BET surface area analysis, 13C CP-MAS NMR spectroscopy. The catalyst found efficient for various isatin derivatives to give good yield and enanioselectivity upto 98%. Further catalyst works well up to five cycle without losing its merit.