Abstract: One chiral form of a 1-aryl-2-aminopropane is produced in preference to its enantiomer by allowing a 1-arylpropan-2-one to react with a 1-amino-1-phenylethane of predominantly one chiral form and reducing the resultant 1-(1-arylprop-2-ylideneimino)-1-phenylethane to yield phenylethane and a mixture of 1-aryl-2-aminopropanes in which one chiral form thereof is present in preference to its enantiomer. The mixture of 1-aryl-2-aminopropanes then is subjected to the action of an omega-amino acid transaminase which converts one of the two chiral forms of 1-aryl-2-aminopropane into the corresponding arylpropanone which can be separated from the remaining chiral form of the 1-aryl-2-aminopropane.