Synthesis 2007(6): 918-928  
DOI: 10.1055/s-2007-965937
PAPER
© Georg Thieme Verlag Stuttgart · New York

Synthesis of γ-Amino Acid Esters by 1,4-Addition of Deprotonated α-Aminonitriles and α-(Alkylideneamino)nitriles to α,β-Unsaturated Esters

Ines Bergner, Till Opatz*
Institut für Organische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
Fax: +49(6131)3924786; e-Mail: opatz@uni-mainz.de;
Further Information

Publication History

Received 20 September 2006
Publication Date:
20 February 2007 (online)

Abstract

α-Aminonitriles and α-(alkylideneamino)nitriles can serve as readily available α-aminocarbanion equivalents. Their conjugate addition to α,β-unsaturated esters followed by reduction furnishes polysubstituted γ-amino acid esters in moderate to high yield.

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A NOESY-spectrum of trans-8d was recorded and the distance between H4 and H5 was calculated from the cross-peak volume integrals using the diastereotopic NCH2 protons as a reference. The obtained value (3.3 Å) was in good accordance with a 3D model of the trans-isomer (3.1 Å) but not with the cis-isomer (2.4 Å). Moreover, a transient NOE experiment on trans-8d revealed a close contact between H4 and one of the benzylic protons of the substituent in 5-position. The γ-lactam obtained by cyclization of 7d was not identical with trans-8d.

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CCDC 621580 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.