Preparation of enantiomerically enriched amine-functionalized compounds

Process for removing a residual fragment of a chiral auxiliary in the preparation of an enantiomerically enriched, amine-functionalized compound with formula 1

• 6
• in which R2, R3, R4 are each different and stand for H, a substituted or unsubstituted (cyclo)alkyl group, alkenyl group, aryl group, cyclic or non-cyclic heteroalkyl or heteroaryl group with one or more N—, O—or S-atoms, or (CH2)n-COR6, where n=1, 2, 3 . . . 6 and R6═OH, a substituted or unsubstituted alkyl group, aryl group, alkoxy group or amino group, in which a diastereomeric compound with formula 2
• 7
• in which R2, R3 and R4 are as defined above, and R1 and R5 are each different and R1 stands for a modified or unmodified side tail of a proteogenous amino acid or a substituted or unsubstituted phenyl group, R5 stands for H or a lower alkyl group, and in which X═O and Y═OR, where R represents H or a C1-C7 alkyl group, or NR7R8, where R7 and R8 each independently represent H, a (cyclo)alkyl group, alkenyl group or aryl group, or X and Y together stand for N, is subjected to a non-reductive removal of the residual fragment of the chiral auxiliary, the carbon atom which is removed having an oxidation state of +3 which is not lowered during the method of removal.