Asymmetric epoxidation of unfactionalized olefins catalyzed by chiral salen Mn(III) immobilized onto sulfoalkyl modified zirconium poly(styrene-isopropenyl phosphonate)-phosphate and zirconium poly(styrene-phenylvinyl phosphonate)-phosphate

Chiral salen Mn(III) complex has been supported onto sulfoalkyl-modified zirconium poly(styrene-isopropenyl phosphonate)-phosphate and zirconium poly(styrene-phenylvinyl phosphonate)-phosphate (ZPS-IPPA and ZPS-PVPA) by axial coordination. The supported catalysts showed higher chiral induction for enantioselective epoxidation of styrene, α-methylstyrene and indene than its homogeneous chiral salen Mn(III). In addition, ZPS-PVPA-supported catalyst (4c), with a larger pore diameter, was found to be more active than ZPS-IPPA-based catalyst (3c). The influence of the linkage lengths on the catalytic performance was investigated. What's more, the catalysts were easily separated from the reaction systems and could be reused for several times without significant loss of catalytic activity.

Chiral salen Mn(III) complex has been supported onto sulfoalkyl modified zirconium poly(styrene-isopropenyl phosphonate)-phosphate and zirconium poly(styrene-phenylvinyl phosphonate)-phosphate (ZPS-IPPA and ZPS-PVPA).Figure optionsDownload as PowerPoint slideHighlights
► A special type of hybrid material was easily prepared in mild conditions.
► The catalysts were conveniently separated from the reaction system.
►  All the immobilized catalysts exhibited great activity and enantioselectivity.
► These catalysts showed better catalytic effect for bulkier olefins such as indene.