A process for the separation of the enantiomers of a compound of formula I wherein X denotes O or CH 2, Y is NH, and n denotes 0 or 1, comprising the steps of: a) contacting the respective racemate or other enantiomeric mixture of the respective compound of formula I with a chiral, non-racemic acid in a suitable solvent, wherein the chiral, non-racemic acid is selected from (1R or 1S)-10-camphorsulfonic acid, (1R or 1S)-3-bromocamphor-10-sulfonic acid, (D or L)-tartaric acid and substituted analogues such as (D or L)- diacetyltartaric acid, (D or L)-dibenzoyl tartaric acid, (D or L)-di-O,O'-p-toluoyl-tartaric acid, (D or L)-di-O,O'-o-toluoyl-tartaric acid, (R or S)-1,1"-binaphthyl-2,2"-diyl-hydrogenphosphate, (D or L)-N-acetyl-phenylalanine, (D or L)-acetylmandelic acid, (R or S)-cyclohexylphenylglycolic acid, -camphanic acid, (R or S)-2-pyrrolidone-5-carboxylic acid, naproxen, ibuprofen; (D or L)-malic acid, L-lactic acid, (R or S)-3-hydroxybutyric acid, hyodeoxycholic acid, (R or S)-mandelic acid, (R or S)-Me-mandelic acid, (R or S)-4-bromo-mandelic acid, (R or S)-4-chloro-mandelic acid or (R or S)-phenylsuccinic acid, or suitable N-protected amino acids, or substituted (D or L)-tartaric acids; b) optionally heating the mixture obtained under step a) and allowing the mixture to cool to room temperature; c) separating the formed crystals from the solution; d) optionally liberating the free base of the respective enantiomer of formula I from the formed crystals obtained under c) by treatment with a base. X denotes O or CH 2, Y is NH, and n denotes 0 or 1, comprising the steps of: a) contacting the respective racemate or other enantiomeric mixture of the respective compound of formula I with a chiral, non-racemic acid in a suitable solvent, wherein the chiral, non-racemic acid is selected from (1R or 1S)-10-camphorsulfonic acid, (1R or 1S)-3-bromocamphor-10-sulfonic acid, (D or L)-tartaric acid and substituted analogues such as (D or L)- diacetyltartaric acid, (D or L)-dibenzoyl tartaric acid, (D or L)-di-O,O'-p-toluoyl-tartaric acid, (D or L)-di-O,O'-o-toluoyl-tartaric acid, (R or S)-1,1"-binaphthyl-2,2"-diyl-hydrogenphosphate, (D or L)-N-acetyl-phenylalanine, (D or L)-acetylmandelic acid, (R or S)-cyclohexylphenylglycolic acid, -camphanic acid, (R or S)-2-pyrrolidone-5-carboxylic acid, naproxen, ibuprofen; (D or L)-malic acid, L-lactic acid, (R or S)-3-hydroxybutyric acid, hyodeoxycholic acid, (R or S)-mandelic acid, (R or S)-Me-mandelic acid, (R or S)-4-bromo-mandelic acid, (R or S)-4-chloro-mandelic acid or (R or S)-phenylsuccinic acid, or suitable N-protected amino acids, or substituted (D or L)-tartaric acids; b) optionally heating the mixture obtained under step a) and allowing the mixture to cool to room temperature; c) separating the formed crystals from the solution; d) optionally liberating the free base of the respective enantiomer of formula I from the formed crystals obtained under c) by treatment with a base. a) contacting the respective racemate or other enantiomeric mixture of the respective compound of formula I with a chiral, non-racemic acid in a suitable solvent, wherein the chiral, non-racemic acid is selected from (1R or 1S)-10-camphorsulfonic acid, (1R or 1S)-3-bromocamphor-10-sulfonic acid, (D or L)-tartaric acid and substituted analogues such as (D or L)- diacetyltartaric acid, (D or L)-dibenzoyl tartaric acid, (D or L)-di-O,O'-p-toluoyl-tartaric acid, (D or L)-di-O,O'-o-toluoyl-tartaric acid, (R or S)-1,1"-binaphthyl-2,2"-diyl-hydrogenphosphate, (D or L)-N-acetyl-phenylalanine, (D or L)-acetylmandelic acid, (R or S)-cyclohexylphenylglycolic acid, -camphanic acid, (R or S)-2-pyrrolidone-5-carboxylic acid, naproxen, ibuprofen; (D or L)-malic acid, L-lactic acid, (R or S)-3-hydroxybutyric acid, hyodeoxycholic acid, (R or S)-mandelic acid, (R or S)-Me-mandelic acid, (R or S)-4-bromo-mandelic acid, (R or S)-4-chloro-mandelic acid or (R or S)-phenylsuccinic acid, or suitable N-protected amino acids, or substituted (D or L)-tartaric acids; b) optionally heating the mixture obtained under step a) and allowing the mixture to cool to room temperature; c) separating the formed crystals from the solution; d) optionally liberating the free base of the respective enantiomer of formula I from the formed crystals obtained under c) by treatment with a base.