ChemInform Abstract: Highly Enantioselective Epoxidation of Unfunctionalized Olefins Catalyzed by Chiral Jacobsen′s Catalyst Immobilized on Phenoxy‐Modified Zirconium Poly(styrene‐phenylvinylphosphonate)phosphate.

Chiral MnIII (Salen) Covalently Bonded on Modified ZPS-PVPA and ZPS-IPPA as Efficient Catalysts for Enantioselective Epoxidation of Unfunctionalized Olefins

“…Moreover, the immobilized catalysts could be reused at least 10 times without significant loss of activity and enantioselectivity. Furthermore, a point worth emphasizing is that ZPS-PVPA-based catalyst results in remarkable increase of conversion and ee values in the absence of expensive O-coordinating axial additive for the asymmetric epoxidation of olefins [ 23 , 24 ], which is exactly opposite to the literature reported earlier for both homogeneous and heterogeneous systems [ 25 , 26 ]. This novel additive effect was mainly attributed to the support ZPS-PVPA and the axial phenoxyl linker group.…”

“…Hutchings [ 31 ] found that the confinement effect originated from the zeolite cage could improve the chiral induction for the asymmetric epoxidition of styrene. It was deduced that the data of increase in enantiomeric excess is mainly attributed to the microenvironment effects of ZPS-PVPA and ZPS-IPPA immobilized Mn III (salen) [ 16 , 17 , 22 , 23 ], which result from the layered structure, micoropores, and channels; the hydrophilic property of polystyrenylphosphonate parts; and hydrophobic of zirconium parts of the hybrid zirconium phosphonate. These features are different from either pure polystyrene or pure zirconium.…”

Chiral MnIII (Salen) Immobilized on Organic Polymer/Inorganic Zirconium Hydrogen Phosphate Functionalized with 3-Aminopropyltrimethoxysilane as an Efficient and Recyclable Catalyst for Enantioselective Epoxidation of Styrene

“…The results show that the heterogeneous catalysts efficiently promoted the enantioselective epoxidation of styrene (entries 2, 3, and 4), as the ee obtained is higher than that of the corresponding homogeneous catalyst ( ee %, 53.3–63.9 vs. 46.2, Table 1 ). The increase in chiral recognition is mainly attributed to the microenvironment effects of the organic polymer–inorganic zirconium hydrogen phosphate immobilized Mn III (salen) [ 15 , 16 , 17 , 18 , 19 ]. The microenvironment effects originated from the layered structure, micoropores, and channels, and the hydrophilic property of the polystyrenylphosphonate parts and hydrophobic property of the zirconium parts of the hybrid zirconium phosphonate.…”

“…The conversion and ee values of styrene epoxide was determined by GC, with n -nonane as an internal standard. The racemic sample of the epoxide was independently prepared by the epoxidation of styrene with m -CPBA in CHC1 3 at 0 °C, and detected by GC [ 18 ].…”

“…More importantly, these support materials possess better thermal and mechanical stability during reaction. In previous works, a series of organic polystyrene–inorganic zirconium phosphate hybrid materials, including zirconium oligostyrenylphosphonate-phosphate (ZSPP) [ 15 ], zirconium poly(styrene-isopropenyl-phosphonate)-phosphate (ZPS-IPPA) [ 16 ], and zirconium poly(styrene-phenylvinyl-phosphonate)-phosphate (ZPS-PVPA) [ 17 , 18 , 19 ], were reported by our group. These hybrid materials, which were frequently functionalized on the benzene ring in the organic component, have been demonstrated to be a versatile support to immobilize homogeneous chiral Mn III (salen) complexes.…”