Asymmetric Michael Reaction In The Construction Of Oxazolidine And Enantioselective Michael Reaction In Water

Ever since its discovery,Michael addition has been a very popular reaction among organic chemists.Based on the important significance of Michael reaction,a chiral N,O-ketals was developed via an asymmetrical Michael reaction.To further investigate the Michael reaction,a series of novel Schiff based ligands were designed and synthesized for the asymmetric Michael reaction in water.Then,the dissertation will be introduced from three sections.In section one,we developed an efficient asymmetric formal[3+2]annulation with quinine-based derivatives as catalysts.This novel approach provided a straightforward access to the N,O-ketal and fluoroalkylated structure motifs which could greatly enhance the pharmacological and agrochemical activities.The detailed mechanism study revealed the excellent enantioselectivity generated from the final aza-Michael addition step.In section two,we designed and prepared a series of Schiff based ligands,which were tertiary amines derived from amino acids.Moreover,these ligands mixed with CuBr2 can afford the water-soluble ammonium salts in situ,giving new catalytic systems for the Michael addition of pyrroles to nitroalkenes in water.By virtue of this water-soluble catalytic system,we developed a Lewis acid catalyzed Michael addition with carbon nucleophiles in water,delivering a series of nitroethylpyrrole derivatives with excellent yields and enantioselectivities.In section three,a series of novel Schiff based ligands,which mixed with Lewis acids to provid surfactant-like catalysts,were designed and synthesized.Using this emulsion catalytic system,we developed a Lewis acid catalyzed asymmetric Michael addition of indole to 2-enoylpyridine 1-oxides,delivering the corresponding products with excellent yields and enantioselectivities.Spherical micelles were clearly observed with an average diameter of 1-2 ?m by metalloscope and confocal laser scanning microscope which confirmed that the reaction took place at the interface of water/oil biphase emulsion droplets.In conclusion,this dissertation is mainly about the research of Michael addition reaction.Based on asymmetric Micheal addition,a chiral C-O bond delivering chiral N,O-ketals was developed via a formal[3+2]annulation of p-quinol with fluoroalkylated hemiaminal.Additionally,a series of novel Schiff based ligands were designed and synthesized for the asymmetric Michael reaction in water.By using these novel catalytic systems,we developed a Lewis acid catalyzed asymmetric Michael addition of indole to 2-enoylpyridine 1-oxides and a Lewis acid catalyzed asymmetric Michael addition of pyrrol to nitroalkene,delivering the corresponding products with excellent yields and enantioselectivities.