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Synthesis 2005(11): 1751-1756  
DOI: 10.1055/s-2005-870007
PAPER
© Georg Thieme Verlag Stuttgart · New York

Diastereo- and Enantioselective Synthesis of 2-Substituted 1-Aminocyclo­propane-1-Carboxylic Acids. Application to the Synthesis of Protected 2,3-Methano Analogs of Ornithine and Glutamic Acid

Jeffrey A. Frick*a,b, John B. Klassena, Henry Rapoporta
a Department of Chemistry, University of California at Berkeley, Berkeley, CA, 94720, USA
b Department of Chemistry, Illinois Wesleyan University, PO Box 2900, Bloomington, IL, 61702-2900, USA
Fax: +1(309)5563864; e-Mail: jfrick@iwu.edu;
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Publication History

Received 28 July 2004
Publication Date:
29 June 2005 (online)

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Abstract

An enantiodivergent synthesis of protected 2,3-methano amino acid analogs is described. (R)-2-benzyloxyethyloxirane, prepared from (S)-aspartic acid, was reacted with tert-butyl hydrogen malonate and further transformed into an enantiomeric pair of intermediate cyclopropane-fused-lactones, 1-carboxy-2-oxo-3-oxabicyclo[4.1.0]heptane. Each of these enantiomers allowed differentiation of the carboxy functions and generation of a 2-hydroxyethyl group on the cyclopropanes, thus affording access to any or all four stereoisomers. The two-carbon pendant allowed for the direct synthesis of protected 2,3-methano analogs of glutamic acid and ornithine and can be used for other useful transformations.

Key words

amino acids - asymmetric synthesis - chemoselectivity - chiral pool - protecting groups - cyclopropanes