A novel example of chiral counteranion induced enantioselective metal catalysis: The importance of ion-pairing in copper-catalyzed olefin aziridination and cyclopropanation

[GRAPHICS] A new ion-pairing route to achieve asymmetric catalysis has been observed i n the copper-catalyzed aziridination of styrene with a chiral counteranion. Structural studies suggest that enantioinduction occurs via ion-pairing of the cationic copper catalyst in the chiral pocket created by the anion, Th e degree of asymmetric induction can be tuned with features that affect ion -pairing, such as achiral and chiral ligands, temperature, and solvent pola rity.