The Design Of Amphiphilic Organocatalyst And Its Application In Emulsion Catalysis

The use of emulsions as media for asymmetric reaction not only can enhance reaction rate, but control the regioselectivity, emulsion catalysis is developing a hot research field in recent years. In this paper, we developed a new type of emulsion catalysis system, and shown to be very effective for two kinds of reactions with high enantioselectivity. The main results are as follows:1. A series of amphiphilic proline-derived mercapto imidazole organic catalysts were synthesized and shown to be very effective with an acid cocatalyst for the asymmetric Michael addition reaction of ketones to aromatic nitroolefins and aliphatic nitroolefins with high diastereoselectivity (up to99:1) and execellent enantioselectivity (up to96%) using water as solvent. This method was found to be extensively applicable.2. A series of amphiphilic mercapto imidazole organic catalysts derived from phenylalanine were synthesized and applied to the reaction of cyclohexanone and β,γ-unsaturated ketones acid ester in emulsion system, an aldol reaction product was obtained with an acid cocatalyst. However a Michael [3+3] annulation product was obtained when the type of secondary amine catalyst was used with an acid cocatalyst. Especially that the reaction rate can be improved considerablely in emulsion system compared to that in homogeneous system. Both reactions were catalyzed effectively and with excellent enantioselectivity(up to97%) and this method was found to be extensively applicable.