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Synthesis 2003(11): 1679-1682
DOI: 10.1055/s-2003-40885
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Ethyl 2,4-Dioxo-4-phenylbutyrate: A Versatile Intermediate for the Large-Scale Preparation of Enantiomerically Pure α-Hydroxy and α-Amino Acid Esters

Hans-Ulrich Blaser*a, Stephan Burkhardta,b, Hans Jürg Kirnerb, Tanja Mössnerb, Martin Studera
a Solvias AG, Postfach 4002 Basel, Switzerland
Fax: +41(61)68666100 ; e-Mail: Hans-Ulrich.Blaser@solvias.com;
b Ciba Specialty Chemicals, Postfach 4002 Basel, Switzerland
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Publication History

Received 12 June 2003
Publication Date:
25 July 2003 (online)

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Abstract

Starting from ethyl 2,4-dioxo-4-phenylbutyrate, both enantiomers of six enantiomerically pure α-hydroxy and α-amino acid esters (homophenylalanine derivatives) were prepared on >100 g scale. The key step involves a Pt-cinchona catalyzed enantioselective hydrogenation followed by enrichment via crystallization. All derivatives are commercially available.

Key words

hydrogenation - enantioselective synthesis - α-keto ester - α-hydroxy ester - homophenylalanine

    References

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Exner, C.; Pfaltz, A.; Studer, M.; Blaser, H.-U. Adv. Synth. Catal., submitted.