Nicholas Turner and Matthew Truppo from the University of Manchester and a co-worker from Codexis Incorporated, California, have synthesised a range of enantiomerically pure (R)- and (S)-configured chiral amines.

Enantiomerically pure chiral amines are important as they have applications in a number of different areas including building blocks for pharmaceuticals, resolving agents and ligands for asymmetric synthesis. In order to minimize the cost of production it is important to devise efficient catalytic methods for their preparation, particularly on a large scale. 

Turner and his team have developed a novel biocatalytic system, involving the use of two enzymes (transaminase and amino acid oxidase), for the kinetic resolution of a range of racemic amines. Both (R)- and (S)-configured chiral amines can be prepared using this approach with high enantioselectivity (e.e. >99%). Turner explains that 'the key to our method is to use a catalytic (as low as 0.05 mol%) quantity of the amine acceptor pyruvate, which is converted to alanine during the transamination of a ketone substrate. The addition of L- or D-amino acid oxidase results in the efficient conversion of the alanine back to pyruvate.' 

'The process is fast, generally applicable, and should be amenable to rapid scale-up by those in industry wishing to apply this method to specific chiral amines of interest,' says Turner.

Emma Shiells