Enantioselective phase transfer alkylation using orthopalladated complex in chiral ionic liquid

The optically active orthopalladated phenanthrylamine phase transfer catalyst has been produced and explored for asymmetric glycine alkylation. The catalyst (10 mol%) in toluene/chloroform with 50% aqueous KOH (25 °C) promoted benzylation of benzophenone imine tert-butyl glycine. The product was obtained in 85% yield and 15% enantiomeric excess (ee). Addition of the chiral ionic liquid N,N-dimethyl ephedrinium bis(trifluoromethansulfon)imidate enhanced reactivity and selectivity for PTC glycine alkylation. It appears that the chiral ionic liquid has a cooperative effect to boost the ee content of an asymmetric reaction.