Axially dissymmetric binaphthyldiimine chiral salen-type ligands for copper-catalyzed asymmetric aziridination

Abstract

Axially dissymmetric chiral salen-type ligands 1– 4 and 7 were prepared from the reaction of ( R)-(+)-1,1′-binaphthyl-2,2′-diamine with 2,6-dichlorobenzaldehyde, 2,3-dichlorobenzaldehyde, 3,4-dichlorobenzaldehyde or salicylaldehyde in high yields, respectively. The catalytic asymmetric aziridination of alkenes has been examined using these novel chiral ligands. Excellent enantioselectivity in the aziridination of cinnamates has been achieved using the C 2-symmetric chiral ligand 1.