Asymmetric transition metal catalysis using racemic ligands can be accomplished in chiral ionic liquids report chemists in Germany. 

Asymmetric catalysis usually requires the use of enantiopure chiral ligands in combination with a transition metal. Preparation of the ligands often requires separation of the enantiomers, which can be difficult or time-consuming. 

Giancarlo Franciò, at RWTH Aachen, Germany, and colleagues used a rhodium catalyst with racemic tropoisomeric ligands for the hydrogenation of alkenes. When the reaction was performed in a chiral ionic liquid, Franciò observed remarkable enantioselectivity. 

'In this approach, the chiral information is provided by the reaction medium,' said Franciò. 'We are fascinated by the possibility to achieve an effective enantiodiscrimination through the interactions of the catalyst with its environment.' 

Franciò plans to investigate the use of different ligand systems and substrates and hopes to extend the approach to other catalytic reactions. 

'The understanding of the reaction mechanism and the basis of chirality transfer will be of fundamental importance to guide the further development,' he said. 

Joanne Thomson