Deracemisation methods

New methods continue to be developed for the dynamic kinetic resolution (DKR) and deracemisation of racemic chiral compounds, in particular alcohols, amines and amino acids. Many of the DKR processes involve the combination of an enantioselective enzyme, often a lipase or protease, with a metal racemisation catalyst. A greater range of ruthenium-based racemisation catalysts is now available with some showing good activity for the racemisation of amines that are more difficult to epimerise than the corresponding alcohols. In terms of deracemisation processes, further improvements have been achieved with the deracemisation of alcohols, using combinations of stereocomplementary ketoreductases, and additionally transaminases have been applied to the deracemisation of racemic amines.