| In this thesis, fourteen novel enantiopure ferrocenyl aziridino alcohols as chiral ligands were designed and synthesized from readily available natural L-amino acids. The systematic studies on these chiral ligands possessing two central chiralities and C2-symmetrical axial chirality were carried out for the application in the catalytic asymmetric addition of diethyl zinc to aldehydes.1. The synthesis of chiral ferrocenyl aziridino alcohol ligands with twostereogenic carbons and their application in the asymmetric catalysis of aldehydesL -threonine (25,35) was obtained from easily available L -threonine (2S,3R) after four steps, then seven chiral ligands 9a-9g were prepared by the esterification, condensation, reductive alkylation, cyclization, then reduction with treatment withRMgX. All nine kinds of novel compounds were characterized by 1H NMR, 1C NMR, IR, HRMS, and the specific rotation were recorded. Compound 9a was further characterized by X-ray diffraction.The X-ray structure analysis revealed that an intermolecular hydrogen bond is present.The effect of the the configurtion of methy group on the aziridine ring on the reactivity and enantioselectivity of reaction was investigated in the asymmetric addition of diethylzinc to aldehydes. It was shown that the configuration of methyl group has great effect on the enantioselectivity , but the absolute configuration of the product was not affected. In the optimized condition, the reaction of diethyl zinc with arylaldehydes gave the corresponding alcohols in 99% chemical yields and up to 100% ee.2. The synthesis of chiral ferrocenyl aziridino alcohol ligands with C2-asymmetry and their application in the asymmetric catalysis of aldehydesSeven novel chiral C2-asymmetric 1,1 -disubstituted ferrocenyl aziridino alcoholligands 18a-18g were synthesized and characterized by 1H NMR, 1C NMR, IR, HRMS respectively. The chiral ligands 18a-18g were used to catalyzed the reaction of diethylzinc with aldehydes. Only in the presence of 0.5% of 18g, up to 87% ee was obtained. Comparing to the chiral ligand 9g possessing two central chrirality, ee increased from 41.7% to 89.0%. This result suggested that the matching of axial and central chiralities was essential for obtaining excellent asymmetric induction and also demonstrated that the axial chirality was important. In the optimized condition, the reaction of diethyl zinc with arylaldehydes gave the corresponding alcohols in 98% chemical yields and up to 100% ee. |
