| 摘要 |
A process for making enantiomerically enriched 4-piperidinylglycine having the formula (I),said process comprising (a) combining N-protected glycine ester with 4-piperidone to form didehydroamino acid ester; (b) reducing the didehydroamino acid ester with hydrogen gas in the presence of a rhodium catalyst selected from the group consisting of (R,R)-BPE-Rh; (S,S)-BPE-Rh; (R,R)-DuPHOS-Rh; (S,S)-DuPHOS-Rh; and combinations thereof; whereby a protected compound is formed; and (c) removing the protecting groups from the protected compound, whereby the 4-piperidinylglyeine having the formula (I) is formed, wherein X<- >is an anion wherein X is independently a halogen; and "*" designates an asymmetric carbon having (R)- or (S)-configuration. The process of the invention yields an enantiomerically enriched (R)-4-piperidineglycine or (S)-4-piperidineglycine.
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