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α‐Amino Acid Derivatives by Enantioselective Decarboxylation
Author(s) -
Brunner Henri,
Baur Markus A.
Publication year - 2003
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200300206
Subject(s) - chemistry , decarboxylation , enantioselective synthesis , benzamide , catalysis , amino acid , organic chemistry , base (topology) , stereochemistry , biochemistry , mathematical analysis , mathematics
The methodology of enantioselective decarboxylation was applied to 2‐aminomalonic acid derivatives in order to obtain enantio‐enriched amino acid derivatives. Full conversion was achieved stirring racemic N ‐acetylated 2‐aminomalonic hemiesters in THF at 70 °C with 10 mol % of a chiral base for 24 h. The catalyst may be recycled. Whereas the commercially available cinchona alkaloids gave poor results, benzamide and benzenesulfonamide derivatives of 9‐amino(9‐deoxy)epicinchonine turned out to be effective catalysts. The best result was obtained with 2‐ N ‐acetylamino‐2‐ethoxycarbonyl‐3‐phenylpropionic acid as the starting material and N ‐(9‐deoxyepicinchonine‐9‐yl)‐4‐methoxybenzamide as the chiral base to give ethyl N ‐acetyl‐ L ‐phenylalaninate in 70% ee . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)