title: Efficient protocols for the synthesis of enantiopure gamma-amino acids with proteinogenic side chains.
abstract: The synthesis of enantiopure gamma-substituted gamma-amino acids with proteinogenic side chains, starting from the corresponding natural alpha-amino acids, was studied. N-Protected amino aldehydes containing various protective groups were prepared from the corresponding amino alcohols by oxidation with NaOCl in the presence of AcNH-TEMPO and directly reacted with methyl, benzyl and tert-butyl phosphoranylidene acetate to produce alpha,beta-unsaturated gamma-amino esters. Simultaneous hydrogenation of the double bond and removal of either the benzyl or benzyloxycarbonyl group led to N- or C-protected gamma-amino acids in high yield. The enantiomeric purity was studied by 1H NMR analysis of Mosher amides and chiral HPLC analysis.
authors.affiliation: Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece.
authors.forename: Vassilios
authors.initials: V
authors.lastname: Loukas
authors.forename: Caterina
authors.initials: C
authors.lastname: Noula
authors.forename: George
authors.initials: G
authors.lastname: Kokotos
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry; D000605:Amino Alcohols / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006865:Hydrogenation; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D000596:Amino Acids; D000605:Amino Alcohols