Novel Chiral Amines: Design, Preparation And Properties In Chiral Recognition And Asymmetric Organocatalysis

In this dissertation, the recent advances in the asymmetric organocatalysis and especially in chiral amine catalyzed enantioselevtive Michael addition reactions were summarized and reviewed. Then, novel classes of chiral amines were extensively studied on their design, preparation, characterization and properties in chiral recognition and asymmetric organocatalysis.Firstly, a novel class of ionic chiral amines （ICAs） was designed and synthesized efficiently from natural amino acids. They could behave like ionic liquids with low melting point （T_m） or glass transition temperature （T_g） and good thermal stability (T_dec≥210℃). X-ray diffraction analysis result confirmed their netlike supramolecular structures formed through the hydrogen bonding and the electrostatic attraction. The NMR chiral recognition study indicated that these novel ICAs could provide efficient chiral environment and good enantiometic discrimination to Mosher acid was achieved by ¹⁹F NMR.Secondly, the novel chiral-amine-thioimidazoles were designed and synthesized by treating （S）-bromine-substituted alkylamine hydrongen bromide salt with 1-alkyl-2-mercaptoimidazole, and their structures were characterized by NMR、IR、MS and X-ray diffraction analysis. ¹⁹F NMR and ¹H NMR measurements also indicated that they had excellent enantiomeric acid recognition properties due to their multifunctionalties.Thirdly, novel pyrrolidinyl-thioimidazolium salts were developed as chiral multifunctional organocatalysts. ESI-MS spectrometric detection gave the apparent evidence for the ionic organocatalyst coordination ability of polyethylene glycols （PEGs） to form the like supramolecular structure. The unique stable PEGs-ionic-pyrrolidine complex was applied as a highly efficient and reusable system for the direct enantioselective Michael addition of ketones to nitroalkenes with 70～97% yields and up to 99% ee enantioselectivities obtained. The complex system and the resulting freely dissociable anion were considered to distribute to the excellent performance of the organocatalysts.Lastly, the novel （S）-pyrroline-thioimidazolium salts were further applied and exhibited good catalytic performance in the asymmetric Michael-aldol tandem reactions ofα,β-unsaturated aldehydes and 2-hydroxybenzaldehyde to form the chiral benzopyran derivatives as well. The desired products were S configuration escess.