両親媒性高分子を利用する高分子固定化型不斉触媒の創製

概要

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The heterogeneous chiral catalysts for the synthesis of optically active compounds have been energetically developed mainly due to their easy separation and recycle use. However, the supported catalysts sometimes lead to negative effects both on the reactivity and the enantioselectivity. Design of the polymer–support is important issue to develop essentially useful polymeric chiral catalyst. We have designed novel polymer–immobilized chiral catalysts based on the use of amphiphilic polymer support. For example, polymers having quaternary ammonium sulfonate pendant groups were efficiently used as suitable polymer support of the chiral catalyst for the reactions in aqueous solution. By using of the amphiphilic polymer–immobilized chiral catalyst, asymmetric transfer hydrogenation in water smoothly occurred to give the corresponding optically active alcohol with positive effect on the enantioselectivity. When the enantiopure quaternary ammonium sulfonate was introduced into polymer, asymmetric alkylation of glycine derivatives can be catalyzed by the chiral ammonium polymer. Chiral quaternary ammonium cation was attached to polymeric sulfonate anion through ionic bonding. This immobilization method using ionic bond is substantially useful since any type of chiral quaternary ammonium structure can be immobilized into polymer without any additional chemical modification on the catalyst molecule.
2009-10-01