Chiral Secondary Amines Catalyzing Asymmetric Michael Reactions

Because of its good catalytic properties showed in various asymmetric reactions, organic catalysis is considered to be very high performance and great potential asymmetric synthesis method, which has attracted a lot of attentions. This paper systematically summarizes and reviews the research status of several kinds of typical chiral secondary amine catalysts in catalytic asymmetric reactions, On this basis, in-depth researches the asymmetric Michael reaction of ketones with α,β-unsaturated aldehydes catalysed by MacMillan catalyst and the asymmetric Michael reaction of ketones with nitroolefin catalysed by prolinol thio-ethers. This paper mainly includes the following three parts:The research status of chiral secondary amines catalysts, especially the Jogensen-Hayashi catalyst, MacMillan catalyst and some other typical chiral secondary amine catalysts for many asymmetric reactions were reviewed.The asymmetric Michael reaction of α, β- unsaturated aldehydes with ketones catalyzed by chiral MacMillan catalyst was researched. It shows that, in DMF, the catalytic system of MacMillan catalyst and HCl can catalyze the asymmetric Michael reaction of cyclohexanone and various α,β- unsaturated aldehydes at room temperature. The Michael products were afforded in good yield (up to 79%) and good enantioselectivities (up to 77%) in 48 h. The Michael product can be further aromatized by dehydrogenation oxidation method in modest yield (up to 40%).The asymmetric Michael reaction of ketones with nitroolefin catalysed by prolinol thio-ethers was studied. In this reaction, the catalytic system of prolinol thio-ethers and benzoic acid showed good catalytic properties. The Michael products were afforded in high yield (up to 98%) and enantioselectivities (up to 99%) with in isopropyl ether in 12 h at room temperature. The Michael product can be further aromatized by bromination -dehydrobromination method in good yield (up to 70%).