Asymmetric synthesis of α-amino acids from α,β-(Z)-didehydroamino acid derivatives with 1,2,3,6-tetrahydropyrazin-2-one structure
作者:Tomás Abellán、Balbino Mancheño、Carmen Nájera、José M Sansano
DOI:10.1016/s0040-4020(01)00553-1
日期:2001.7
structure 10 by condensation with carbonyl compounds, Eschenmoser's salt and Bredereck's reagent, respectively. The didehydroalanine derivative 15 and the enaminone 16 can give DDAA derivatives 14 using Heck olefination and vinylic nucleophilic substitution. These DDAA derivatives 14 and 15 undergo diastereoselective cyclopropanation, 1,3-dipolar and Diels–Alder cycloaddition reactions giving, after
New Chiral Didehydroamino Acid Derivatives from a Cyclic Glycine Template with 3,6-Dihydro-2<i>H</i>-1,4-oxazin-2-one Structure: Applications to the Asymmetric Synthesis of Nonproteinogenic α-Amino Acids
作者:Rafael Chinchilla、Larry R. Falvello、Nuria Galindo、Carmen Nájera
DOI:10.1021/jo991736l
日期:2000.5.1
reactions using Corey's ylide for the asymmetric synthesis of 1-aminocyclopropane-1-carboxylic acids (ACCs) such as allo-corononamic and allo-norcoronamic acids. The hydrogenation reaction of these systems at ambient pressure in the presence of formaldehyde affords saturated oxazinones and N-methylated oxazinones which have been transformed into the N-methyl-alpha-amino acids (N-MAAs) (S)-2-(methylamino)butanoic
(1S,2R)- and (1R,2S)-Allonorcoronamic acids have been efficiently synthesised from the cyclic sulfate of 1,2-propanediol and Belokon's complex (a complex of Ni(II) with glycine-(S)-2-[N '-(N-benzylprolyl)amino]benzophenone Schiff base ligands). The stereochemical outcome of the reaction was totally controlled bq the sulfate partner. (C) 2001 Elsevier Science Ltd. All rights reserved.
A straightforward synthesis of both enantiomers of allo-norcoronamic acids and allo-coronamic acids, by asymmetric Strecker reaction from alkylcyclopropanone acetals
作者:Antoine Fadel、Aballache Khesrani
DOI:10.1016/s0957-4166(97)00633-2
日期:1998.1
Methylcyclopropanone hemiacetal (2S)-3a underwent the asymmetricStrecker reaction induced by a chiral amine to provide a useful synthesis of enantiomerically pure (1R,2S)-(+)-allo-norcoronamic acid 1 in good yield and high enantiomeric excess. From racemic alkyl hemiacetal (±)-3, the same methodology also constituted a useful way to prepare both (+)-1 and (−)-1 and (+)-allo-coronamic acid 2 and its
New α,β-didehydroamino acid derivatives as precursors in the synthesis of 1-aminocyclopropanecarboxylic acids
作者:Carlos Cativiela、María D. Díaz-de-Villegas、Ana I. Jiménez
DOI:10.1016/s0040-4020(01)85381-3
日期:1994.1
idehydroalanine methyl ester with diazoalkanes or ylides gives the corresponding cyclopropane derivatives in high yields. The cis/trans ratio of these compounds was dependent on substrate, reagent and reaction temperature. From stereochemically homogeneous compounds the corresponding 1-aminocyclopropanecarboxylicacids were easily obtained by acid hydrolysis.