Studies On The Enantioselective Construction Of Quaternary Carbon Stereocenters Via The Michael Reaction

The chiral quaternary carbon centers are widely distributed in various bioactive natural products, and its catalytic asymmetric construction is an important research topic in organic synthesis. As one of the strategies for constructing the chiral quaternary carbons, the design and development of novel catalytic asymmetric Michael addition reaction are of great importance in the establishment of chiral quaternary carbons with high efficiency.Oriented toward constructing the key chiral quaternary carbon in the synthesis of some hydroindole alkaloids, this thesis made a preliminary study on the enantioselective Michael addition of a-cyano ketones to acrylates under the asymmetric organocatalysis. We initially investigated various influencing factors including catalysts, solvents, Michael donors and Michael acceptors in this reaction. Under the optimized conditions, the organocatalysts derived from Cinchona alkaloids can provide the better enantioselective control in this asymmetric Michael addition. The present results, to some extent, not only have enriched the chemistry of organocatalytic asymmetric Michael addition, but also could provide an alternative for constructing the functionalized chiral quaternary carbon. Certainly, it also paves the way for the asymmetric synthesis of relevant natural hydroindole alkaloids.