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论文类型：期刊论文

发表时间：2014-10-01

发表刊物：CHINESE JOURNAL OF CHEMISTRY

收录刊物：SCIE、Scopus

卷号：32

期号：10,SI

页面范围：985-990

ISSN号：1001-604X

关键字：emulsion catalysis; asymmetric catalysis; organocatalysis

摘要：A series of of amphiphilic imidazole based secondary and primary amine catalysts were synthesized and shown to be very effective with an acid cocatalyst for the asymmetric reaction of cyclohexanone to ,-unsaturated -keto ester. Interestingly, primary and secondary amine catalysts show different regio-selectivities in this reaction. Under the catalysis of secondary amine 1, excellent enantioselectivities were observed for the products from direct 3+3 reactions of cyclohexanone with ,-unsaturated -keto esters using water as the solvent. Moreover, the same reactants catalyzed by the primary amines 2 lead to the aldol reactions, affording the corresponding products with high diastereoselectivities and up to 97% ee. Theoretical studies on the transition states by using a model in gas phase revealed that steric effect plays an important role on different chemo-selective induction between the secondary amine 1 and primary amine 2.