Synthesis Of Alkoxyl-Modified ZPS-PVPA And Sulfoalkyl-Modified ZnPSPPP Axially Immobilized Chiral Salen Mn(â…¢) Complexes And Their Applications In Asymmetric Epoxidation Of Unfuntionalized Olefins

Chiral salen Mn(â…¢) complexes have proven to be one of the most efficient homogeneous catalysts in the asymmetric epoxidation of unfunctionalized olefins. Compared with the homogeneous catalysts, immobilization of salen Mn(â…¢) catalysts have aroused increasing attentions. New types of supported catalysts were obtained by anchoring chiral salen Mn(â…¢) complex on a series of alkoxyl-modified zirconium poly (styrene-phenylvinyl phosphonate)-phosphate (ZPS-PVPA) in the text. And these catalysts were characterized by FT-IR, UV-vis, XPS, SEM, TEM, N2 absorption, TG and elemental analysis.The catalytic capabilities were investigated with m-CPBA as an oxidant and with indene and a-methylstyrene as substrates for asymmetric epoxidation of unfunctionalized olefins. Contrary to most of the literatures reported, the results showed that the heterogeneous catalysts 3a-f exhibited excellent catalytic activities, and their conversions and ee values increased remarkably in the absent of N-methylmorpholine N-oxide (NMO) under the same catalytic conditions. Futhermore, these prepared catalysts were easily separated and reused ten times without significant loss of activities.In addition, we synthesized chiral salen Mn(â…¢) catalysts axially immobilized onto sulfoalkyl-modified zinc poly (styrene-phenylvinyl phosphonate)-phosphate (ZnPSPPP). These catalysts were characterized with FT-IR, UV-vis, XRD, SEM, TEM and were applied in epoxidation of unfunctionalized olefins. The crystalline support ZnPSPPP was synthesized on mild condition completely differentiated to the traditional methods. The catalysts 6a-c exhibited excellent catalytic activities, and their conversions and ee values also increased remarkably without NMO, further leading us to analysis the reason of this phenomenon.