| 摘要 |
The present invention relates to a process for the preparation of compounds of formula (1), wherein R1 is unsubstituted or substituted C1-C8alkyl or a radical of formula -COOR3, wherein R3 is hydrogen or unsubstituted or substituted C1-C8alkyl, R2 is hydrogen or unsubstituted or substituted C1-C8alkyl, X is the radical -O- or -NH-, Y is hydrogen or an acyl or silyl radical, n is the number 0, 1 or 2, and the chiral carbon atom denoted by the symbol* in the compound of formula (1) is predominantly in pure form in either the R or S configuration, in which process a compound of formula (2) is converted by enantioselective hydrogenation and, where approriate, introduction of the radical Y to form an enantiomeric mixture, enriched with one of the enantiomers (R or S configuration), of the compound of formula (3), and the enantiomeric mixture is separated by enzymatic stereoselective hydrolysis, alcoholysis, aminolysis or ammonolysis, and in the case of the preparation of compounds of formula (1) wherein X is the radical -NH-, the resolution is effected by enzymatic stereoselective aminolysis or ammonolysis in the presence of a compound of formula NH2-R2', wherein R2' is as defined above for R2.
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