Lewis Acid-catalyzed Asymmetric Ring-opening Of Aziridines With Amines:Construction Of Nitrogen-Substituted Quaternary Centers

This thesis mainly focuses on the synthesis of chiral phosphoramide ligands and their applications in Lewis acid catalyzed ring opening reaction of racemic2,2-disubstituted aziridines with amines via kinetic resolution.Following literature methods with necessary modifications,a series of chiral phosphoramide ligands were synthesized from（S）-phenethylamine,2-naphthol and other cheap and readily available reagents,and the new ligands were characterized by spectropic methods and/or x-ray crystallographic analysis.After a screen of various reaction conditions for the asymmetric ring opening reaction of 2,2-disubstituted aziridine by organic amines,the best catalytic system was determined as AgNTf ₂（2.5 mol%）/L22（3 mol%）/m-xylene（0.5 mL）/15°C,which provided the chiral 1,2-diamine products bearing one N-substituted quaternary center with high enantioselectivity（up to 94%ee）and in high yield（up to 99%）.