Enantioselectivity, swelling and stability of 4-hydroxyprolinol containing acrylic polymer beads in the asymmetric reduction of ketones

摘要: Abstract A new 4-hydroxy-α,α-diphenyl- l -prolinol containing polymethacrylate, prepared without chromatography by a large scale adaptable synthesis, has been evaluated as catalyst in the asymmetric reduction of 1-arylethanones. Using 1-(4-bromophenyl)ethanone model substance, was tested with various borane sources and solvents. The best swellings polymer reactivity were observed THF using N , -diethylaniline complex hydride source. selectivity found to depend on substrate concentration loading. conditions identified, series 1-arylethanones reduced their corresponding enantioenriched secondary alcohols. High rates ee-values obtained acetophenones electron withdrawing groups aromatic ring, whereas moderate result for products donating substituents. Upon recovery beads, it that vacuum drying led extensive rupturing, while bead structure intact if washed methanol air dried at atmospheric pressure. Repeated use gave product alcohol lower 90% ee. Elemental analysis showed this be due loss chiral prolinol unit.