Abstract
This review provides a comprehensive treatment of literature data dealing with asymmetric synthesis of α-amino-β-hydroxy and α,β-diamino acids via homologation of chiral Ni(II) complexes of glycine Schiff bases using aldol and Mannich-type reactions. These reactions proceed with synthetically useful chemical yields and thermodynamically controlled stereoselectivity and allow direct introduction of two stereogenic centers in a single operation with predictable stereochemical outcome. Furthermore, new application of Ni(II) complexes of α-amino acids Schiff bases for deracemization of racemic α-amino acids and (S) to (R) interconversion providing additional synthetic opportunities for preparation of enantiomerically pure α-amino acids, is also reviewed. Origin of observed diastereo-/enantioselectivity in the aldol, Mannich-type and deracemization reactions, generality and limitations of these methodologies are critically discussed.
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We thank IKERBASQUE, Basque Foundation for Science; the Basque Government (SAIOTEK S-PE12UN044) and Hamari Chemicals (Osaka, Japan) for generous financial support.
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Sorochinsky, A.E., Aceña, J.L., Moriwaki, H. et al. Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases. Part 2: Aldol, Mannich addition reactions, deracemization and (S) to (R) interconversion of α-amino acids. Amino Acids 45, 1017–1033 (2013). https://doi.org/10.1007/s00726-013-1580-3
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DOI: https://doi.org/10.1007/s00726-013-1580-3