Abstract: A process for obtaining an isomer of a compound of general formulaR--CH(CN)--R' (I)wherein each of R and R' may be any organic radical linked directly or through a heteroatom to the carbon atom bearing the cyano group provided that at least one of R and R' comprises at least one resolved chiral center which is stable under the conditions of the process, or a racemic modification comprising the isomer and its enantiomer, which comprises the step of treating the epimer of the isomer, or the racemate comprising the epimer and the enantiomer of the epimer, in solution in a polar organic solvent, or in slurry in a polar organic liquid diluent in which the epimer or the racemate is partially soluble, with a source of cyanide ions, in the absence of a base, the isomer, or the racemic modification comprising the isomer and its enantiomer, being less soluble in the solvent or diluent than the epimer of the isomer, or the racemate comprising the epimer of the isomer and the enantiomer of the epimer, respectively.