The present invention relates to a process for the preparation of a diastereomerically enriched compound, wherein a first compound according to formula (I), is contacted with a second compound according to formula (II), to form a third compound according to formula (III), whereby the compound according to formula (III) is subsequently reduced and thereby converted into a compound according to formula (IV), in which formulas: R1=a cycloalkyl group whereby R1 # R2, R2=a substituted or unsubstituted: (cyclo)alkyl group, (cyclo)alkenyl group, aryl group, cyclic or acyclic heteroalkyl group or heteroaryl group, R3=an alkyl group, R4=a substituted or unsubstituted: phenyl- or naphthyl-group, *=a chiral center. The invention furthermore relates to a diastereomerically enriched compound according to formula (IV) and its use in the preparation of pharmaceutical and agrochemically active compounds. The invention further relates to a process for the preparation of enantiomerically enriched compounds of formula (V), through hydrogenolysis of diastereomerically enriched compounds of formula (IV), wherein R1 and R2 have the meanings given above.