Efficient asymmetric aldol reaction catalyzed by polyvinylidene chloride-supported ionic liquid/l-proline catalyst system

摘要

A series of polyvinylidene chloride (PVDC)-supported ionic liquids were derived from 4-dimethylaminopyridine and used together with l-proline in water as efficient asymmetric organocatalysts for direct asymmetric aldol reactions between cyclohexanone and a variety of aromatic aldehydes at room temperature. These PVDC-supported ionic liquids/l-proline catalyst systems have been used as asymmetric organocatalysts to afford the corresponding aldol products with a moderate to high isolated yield of up to 99%, with diastereoselectivity of up to 6:94, and excellent enantioselectivity of up to 98%. Furthermore, they could be easily recycled and showed only a slight reduction in selectivity after seven recycles.