Synthesis of α-Amino Acids via Asymmetric Phase Transfer-Catalyzed Alkylation of Achiral Nickel(II) Complexes of Glycine-Derived Schiff Bases
- 30 September 2003
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 125 (42) , 12860-12871
- https://doi.org/10.1021/ja035465e
Abstract
Achiral, diamagnetic Ni(II) complexes 1 and 3 have been synthesized from Ni(II) salts and the Schiff bases, generated from glycine and PBP (7) and PBA (11), respectively, in MeONa/MeOH solutions. The requisite carbonyl-derivatizing agents pyridine-2-carboxylic acid(2-benzoyl-phenyl)-amide 7 (PBP) and pyridine-2-carboxylic acid(2-formyl-phenyl)-amide 11 (PBA) were readily prepared from picolinic acid and o-aminobenzophenone or picolinic acid and methyl o-anthranilate, respectively. The structure of 1 was established by X-ray crystallography. Complexes 1 and 3 were found to undergo C-alkylation with alkyl halides under PTC conditions in the presence of β-naphthol or benzyltriethylammonium bromide as catalysts to give mono- and bis-alkylated products, respectively. Decomposition of the complexes with aqueous HCl under mild conditions gave the required amino acids, and PBP and PBA were recovered. Alkylation of 1 with highly reactive alkyl halides, carried out under the PTC conditions in the presence of 10% mol of (S)- or (R)-2-hydroxy-2‘-amino-1,1‘-binaphthyl 31a (NOBIN) and/or its N-acyl derivatives and by (S)- or (R)-2-hydroxy-8‘-amino-1,1‘-binaphthyl 32a (iso-NOBIN) and its N-acyl derivatives, respectively, gave rise to α-amino acids with high enantioselectivities (90−98.5% ee) in good-to-excellent chemical yields at room temperature within several minutes. An unusually large positive nonlinear effect was observed in these reactions. The Michael addition of acrylic derivatives 37 to 1 was conducted under similar conditions with up to 96% ee. The 1H NMR and IR spectra of a mixture of the sodium salt of NOBIN and 1 indicated formation of a complex between the two components. Implications of the association and self-association of NOBIN for the observed sense of asymmetric induction and nonlinear effects are discussed.Keywords
This publication has 46 references indexed in Scilit:
- Asymmetric PTC C-Alkylation Catalyzed by Chiral Derivatives of Tartaric Acid and Aminophenols. Synthesis of (R)- and (S)-α-Methyl Amino AcidsThe Journal of Organic Chemistry, 2000
- 1,5-Dimethyl-4-phenylimidazolidin-2-one-Derived Iminic Glycinimides: Useful New Reagents for Practical Asymmetric Synthesis of α-Amino AcidsThe Journal of Organic Chemistry, 2000
- Catalytic Asymmetric Strecker Synthesis. Preparation of Enantiomerically Pure α-Amino Acid Derivatives from Aldimines and Tributyltin Cyanide or Achiral Aldehydes, Amines, and Hydrogen Cyanide Using a Chiral Zirconium CatalystJournal of the American Chemical Society, 2000
- Ti-Catalyzed Enantioselective Addition of Cyanide to Imines. A Practical Synthesis of Optically Pure α-Amino AcidsJournal of the American Chemical Society, 1999
- Asymmetric Michael addition of a glycine synthon to methyl methacrylate, mediated by disodium TADDOLateMendeleev Communications, 1997
- Solvent Effects on Homolytic Bond Dissociation Energies of Hydroxylic AcidsJournal of the American Chemical Society, 1996
- Homolytic Bond Dissociation Enthalpies of the Acidic H-A Bonds Caused by Proximate Substituents in Sets of Methyl Ketones, Carboxylic Esters, and Carboxamides Related to Changes in Ground State EnergiesJournal of the American Chemical Society, 1995
- 3‐Amino‐2H‐Azirines. Synthons for α,α‐Disubstituted α‐Amino Acids in Heterocycle and Peptide Synthesis [New Analytical Methods (43)]Angewandte Chemie International Edition in English, 1991
- Detailed stereochemistry in solution of a macrocyclic complex having eight chiral centers. Intramolecular nuclear Overhauser effectJournal of the American Chemical Society, 1973
- Proton magnetic resonance study of the stereochemistry of a macrocyclic Schiff base-amine complex of nickel(II)Journal of the American Chemical Society, 1968