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DOI: 10.1055/s-0039-1690705
Stereoselective Synthesis of syn-γ-Hydroxynorvaline and Related α-Amino Acids
This work was supported by the Agentúra na Podporu Výskumu a Vývoja (Slovak Research and Development Agency) under contract no. APVV-16-0258.Publikationsverlauf
Received: 09. August 2019
Accepted after revision: 17. September 2019
Publikationsdatum:
16. Oktober 2019 (online)


Abstract
The total syntheses of three enantiomerically pure non-proteinogenic amino acids, l-norvaline, γ-oxonorvaline, and syn-γ-hydroxynorvaline, are reported. The chromatography-free route pivoted on the construction of highly enantiomerically enriched substituted α-amino-γ-oxopentanoic acid, from which all three members were accessed divergently via chemoselective and stereoselective reductions. The rapid synthesis of this key α-amino-γ-oxopentanoic acid was achieved by a highly diastereoselective crystallisation-driven three-component Mannich reaction from the readily available building blocks acetone, glyoxylic acid monohydrate, and (S)-(4-methoxyphenyl)ethylamine. The enantiomeric purity of all target molecules was confirmed by HPLC analysis, either of the amino acids or their derivatives.
Key words
stereoselective synthesis - α-amino acids - Mannich reaction - crystallisation-induced - norvaline - γ-hydroxynorvaline - aza-Michael additionSupporting Information
- Supporting information for this article is available online at http://dx.doi.org/10.1055/s-0039-1690705.
- Supporting Information