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 in 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, The degree of asymmetric induction can be tuned with features that affect ion-pairing, such as achiral and chiral ligands, temperature, and solvent polarity.