6232-22-0Relevant articles and documents
Synthesis of Enantio- and Diastereo-isomerically Pure β- and γ-Substituted Glutamic Acids via Glycine Condensation with Activated Olefins
Belokon, Yuri N.,Bulychev, Aleksandr G.,Ryzhov, Mikhail G.,Vitt, Sergei V.,Batsanov, Andrei S.,et al.
, p. 1865 - 1872 (1986)
The glycine fragment in the nickel(II) complex formed from the Schiff base of glycine and (S)-o-benzophenone undergoes base-catalysed Michael addition in methanol in the presence of MeONa to the activated olefins methyl acrylate, acrylonitrile, methyl methacrylate, acrolein, and methyl trans-cinnamate.Complexes of substituted (S)-glutamic acid or its derivatives were formed in good chemical yields with almost complete diastereoselection at the α-carbon atom of the amino acid moiety.Diastereoselection at the β- and γ-atoms was not significant, but the isomeric complexes could be easily separated chromatogrphically.Cleavage of the pure diastereoisomers with aqueous HCl gave, in good yields, optically pure glutamic acids and regenerated the original chiral reagent.The configurations of the amino acid β- and γ-carbon atoms were determined by 1H n. m. r. spectroscopy and crystal structure X-ray analysis of the corresponding original complexes.The addition to acrolein, catalysed by triethylamine in methanol, leads to the 1,4-adduct exclusively.The amino acid thus obtained could be converted into (S)-proline by reduction with NaBH4.
