The Application Of Chiral Ligand Containing Four-membered N-heterocyclic Amino Alcohol Moiety In The Asymmetric Michael Addition Reaction

This thesis mainly studied the application of chiral ligands of the amino alcohol containing four-membered N-heterocyclic structure in asymmetric Michael addition reaction, which has achieved excellent catalytic effect.1 The application of Four-membered N-heterocyclic Silyl Ethers for the Asymmetric Michael Addition Reaction of Aldehyde and Nitroolefins Nitro compounds are a kind of important nitrogen compounds that can undertake transformation through a variety of reactions into different compounds, which are widely applied in organic synthesis. In this thesis, a series of four-membered N-heterocyclic silyl ethers has been synthesized and applied in the asymmetric Michael addition reaction of aldehyde with nitroolefins,.First of all, we have designed and synthesized a series of four-membered N-heterocyclic silyl ethers for the asymmetric Michael addtion reaction of aldehyde with nitroolefins. The optimized reaction conditions show toluene as solvent, 10mol% of DMAP as additive, 10 mol% of 2 as catalyst at room temperature that can get the best catalytic effect. Under the optimum reaction conditions, we investigate the applicable scope of the substrates aldehydes and nitroolefins to explore the generality of this reation. Whether electron-donaing or eletron-withdrawing groups for nitro substrates can get good results, affording the corresponding products in excellent yields(up to 85%) and excellent enantioselectivities(up to 99% ee).According to the reaction mechanism of five-membered N-heterocyclic silyl ether catalyst in the asymmetric Michael addition reaction of aldehyde with nitroolefins, we put forward the possible reaction mechanism.2 The application of chiral aza-semi-crown-ether azetidino alcohol ligand in the catalytic asymmetric addition of 2-hydroxy-2’-methoxya-cetophenone to enones.In this thesis,we have discussed the application of chiral aza-semi-crown-ether azetidino alcohol ligand in the catalytic asymmetric addition of2-hydroxy-2’-methoxy-acetophenone to enones.The chiral ligand L3 and Et2 Zn were used as catalyst to promote the asymmetric Michael addition of 2-hydroxy-2’-methoxyacetophenone to enones affording the corresponding products in up to 97 % enantiomeric excess and in up to 93 %excellent yields.