Large scale enantiomeric synthesis, purification, and characterization of ω-unsaturated amino acids via a Gly-Ni(II)-BPB-complex

Xuyuan Gu, John M. Ndungu, Wei Qiu, Jinfa Ying, Michael D. Carducci, Hank Wooden, Victor J. Hruby

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

The enantiomeric syntheses of ω-unsaturated amino acids and β-substituted ω-unsaturated amino acids were accomplished by using Gly-Ni-2[N-(N′-benzylprolyl)amino]benzophenone (BPB) as a chiral auxiliary. The synthesis provides excellent yields and high diastereoselectivities. The product crystallization followed by isomer epimerization strategy makes the reaction practical and useful for large-scale preparations. Dialkylation of the Ni(II)-complex, which was designed for mechanistic considerations, revealed that high diastereoselectivity is obtained due to the thermodynamic conformational stability of the Ni(II)-complex. The assignment of absolute configuration was accomplished by NMR, which is supported by corresponding X-ray structure and optical rotation data. Both enantiomerically pure amino acids can be synthesized in this alkylation-hydrolysis two-step strategy in multi gram scales.

Original languageEnglish (US)
Pages (from-to)8233-8243
Number of pages11
JournalTetrahedron
Volume60
Issue number37
DOIs
StatePublished - Sep 6 2004

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Keywords

  • Alkylation
  • Amino acids
  • Diastereoselectivity
  • Epimerization
  • Ni(II)-complex chiral auxiliary

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

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