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Synthesis of beta-substituted alpha-amino acids via Lewis acid promoted radical conjugate additions to alpha,beta-unsaturated alpha-nitro esters and amides. 2004

G S C Srikanth, and Steven L Castle
Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.

[reaction: see text] Beta-substituted alpha,beta-unsaturated alpha-nitro esters and amides undergo radical conjugate additions when treated with an appropriate Lewis acid. Deuterium studies revealed that the acidic alpha-stereocenter of the alpha-nitro ester products does not racemize under strictly controlled workup conditions. The alpha-nitro amides did racemize significantly during chromatography, but this could be greatly minimized by subjecting the crude adducts to subsequent transformations. The conjugate addition products can be elaborated into beta-substituted alpha-amino acids in two simple steps.

UI MeSH Term Description Entries
D009566 Nitrates Inorganic or organic salts and esters of nitric acid. These compounds contain the NO3- radical. Nitrate
D009682 Magnetic Resonance Spectroscopy Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING). In Vivo NMR Spectroscopy,MR Spectroscopy,Magnetic Resonance,NMR Spectroscopy,NMR Spectroscopy, In Vivo,Nuclear Magnetic Resonance,Spectroscopy, Magnetic Resonance,Spectroscopy, NMR,Spectroscopy, Nuclear Magnetic Resonance,Magnetic Resonance Spectroscopies,Magnetic Resonance, Nuclear,NMR Spectroscopies,Resonance Spectroscopy, Magnetic,Resonance, Magnetic,Resonance, Nuclear Magnetic,Spectroscopies, NMR,Spectroscopy, MR
D004952 Esters Compounds derived from organic or inorganic acids in which at least one hydroxyl group is replaced by an –O-alkyl or another organic group. They can be represented by the structure formula RCOOR’ and are usually formed by the reaction between an acid and an alcohol with elimination of water. Ester
D005609 Free Radicals Highly reactive molecules with an unsatisfied electron valence pair. Free radicals are produced in both normal and pathological processes. Free radicals include reactive oxygen and nitrogen species (RONS). They are proven or suspected agents of tissue damage in a wide variety of circumstances including radiation, damage from environment chemicals, and aging. Natural and pharmacological prevention of free radical damage is being actively investigated. Free Radical
D000143 Acids Chemical compounds which yield hydrogen ions or protons when dissolved in water, whose hydrogen can be replaced by metals or basic radicals, or which react with bases to form salts and water (neutralization). An extension of the term includes substances dissolved in media other than water. (Grant & Hackh's Chemical Dictionary, 5th ed) Acid
D000577 Amides Organic compounds containing the -CO-NH2 radical. Amides are derived from acids by replacement of -OH by -NH2 or from ammonia by the replacement of H by an acyl group. (From Grant & Hackh's Chemical Dictionary, 5th ed) Amide
D000596 Amino Acids Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins. Amino Acid,Acid, Amino,Acids, Amino
D015394 Molecular Structure The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds. Structure, Molecular,Molecular Structures,Structures, Molecular

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