A poly(hydroxyethyl methacrylate)-immobilized chiral manganese(III)salen catalyst for asymmetric epoxidation of α-methylstyrene

Article abstract of DOI:10.1016/S1872-2067(11)60345-8

Phenylalaninol was introduced in the C5 and C5′ position of a chiral Mn(III)salenCl compound, and the catalyst was then immobilized on poly(hydroxyethyl methacrylate) (pHEMA) by axial coordination. The catalytic system, with (R,R)(R,R)pHEMA-immobilized Mn(III)salenCl as catalyst and [bmim]PF₆ as reaction medium, gave excellent catalytic activity and enantioselectivity with 80-91 ee values and 84-92 yields for the asymmetric epoxidation of α-methylstyrene. The catalyst can be reused several times without significant loss of catalytic activity. This was due to a chiral synergy between the chiral carbons of the amino alcohol and the chiral carbons of (R,R)-diaminocyclohexane.