Sythesis of Chiral Salen Mn(III) Immobilized ...

In the absence of any templated agents, A novel type of organic polymer-inorganic hybrid material layered crystalline zinc poly(styrene-phenylvinylphosphonate)-phosphate (ZnPS-PVPP) was designed and prepared. A series of new heterogeneous catalysts were obtained by grafting chiral salen Mn(III) onto aryldiamine-modified ZnPS-PVPP. The immobilized catalysts revealed much higher ee values for asymmetric epoxidation of a-methylstyrene (ee, >99% vs 54%) and indene (99.9% vs 65.0%) with m-CPBA as oxidant than those of the corresponding homogeneous catalyst and could be reused at least nine times without significant loss of activity and enantioselectivity. Another noteworthy aspect of these heterogeneous catalysts was that it was so reactive that no additional co-catalyst 4-methylmorpholine N-oxide (NMO) was required to increase the reactivity, which provided the potentiality for application in industry.