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%?.