- A chemoenzymatic approach to the synthesis of enantiomerically pure aza analogues of paraconic acid methyl ester and both enantiomers of methyl β-proline
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Enantiopure methyl esters of 1-alkyl-5-oxo-3-pyrrolidinecarboxylic acids were obtained by enzymatic resolution of the corresponding chiral racemic mixtures. A particularly favourable interaction, also supported by molecular mechanics calculations, was observed between the 1-benzyl derivative and α-chymotrypsin, for which the enantiomeric ratio, E, exceeded 200. The absolute configurations of the lactams were determined by means of CD spectroscopy. From the resulting enantiomerically pure (99% e.e.) (S)-(+)-1-benzyl-3-pyrrolidinecarboxylic acid and methyl (R)-(-)-1-benzyl-3-pyrrolidinecarboxylate, the methyl esters of (+) and (-)-β-proline were synthesised in 99% e.e. and 18 and 22% overall yield, respectively.
- Felluga, Fulvia,Pitacco, Giuliana,Prodan, Massimo,Pricl, Sabrina,Visintin, Marco,Valentin, Ennio
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p. 3241 - 3249
(2007/10/03)
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