Glycine Enolate Research Articles

Claisen-type addition of glycine to pyridoxal in water.

The reaction between 5'-deoxypyridoxal and glycine in D2O buffered at pD 7.0 does not result in significant formation of the expected products of pyridoxal-catalyzed transamination or deuterium exchange of the alpha-amino protons of glycine, but rather gives a quantitative yield of the two diastereomeric products of the formal Claisen-type addition of glycine to 5'-deoxypyridoxal. The unexpected extensive formation of these products reflects the extraordinary selectivity of the 5'-deoxypyridoxal-stabilized glycine enolate toward addition to the carbonyl group of 5'-deoxypyridoxal in the protic solvent water.

An Efficient Asymmetric Synthesis of Fmoc‐L‐cyclopentylglycine via Diastereoselective Alkylation of a Glycine Enolate Equivalent.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Stereocontrolled synthesis of 3-(trans-2-aminocyclopropyl)alanine, a key component of belactosin A.

Herein we report a concise synthesis of 3-(trans-2-aminocyclopropyl)alanine, a component of belactosin A, using asymmetric alkylation of a glycine enolate in the presence of chiral phase-transfer catalysts to control the configuration at C2. Reaction of protected glycidol with triethyl phosphonoacetate (Wadsworth-Emmons cyclopropanation) is used for enantiospecific preparation of an intermediate cyclopropanecarboxylate that is converted to a cyclopropylamine via Curtius rearrangement. [reaction: see text]

An efficient asymmetric synthesis of Fmoc- l-cyclopentylglycine via diastereoselective alkylation of glycine enolate equivalent

Stereoselective alkylation of the enolate derived from benzyl (2 R,3 S)-(−)-6-oxo-2,3-diphenyl-4-morpholinecarboxylate ( 1 ) with cyclopentyl iodide afforded anti-α-monosubstituted product, benzyl (2 R,3 S,5 S)-(−)-6-oxo-2,3-diphenyl-5-cyclopentyl-4-morpholinecarboxylate ( 3 ) in 60% yield. Catalytic hydrogenolysis over PdCl 2 cleaved the auxiliary ring system to give l-cyclopentylglycine ( 4 ) in 84% yield. Subsequent protection of the α-amino function with Fmoc-OSu gave Fmoc- l-cyclopentylglycine ( 5 ) in high yield.

Optically pure beta-substituted beta-hydroxy aspartates as glutamate transporter blockers.

A short asymmetric synthesis of optically pure beta-substituted beta-hydroxy aspartates is described. The key step is an aldol reaction between a glycine enolate derived from an oxazinone intermediate used as chiral auxiliary and various alpha-keto esters. Excellent diastereomeric excesses are obtained.

Synthesis of C-Linked Glycopyranosyl Serines via a Chiral Glycine Enolate Equivalent

[formula: see text] The stereoselective preparation of C-linked D-gluco- and D-galactopyranosyl L-serines in their alpha and beta forms is herein reported. The syntheses require the conversion of the allyl C-glycopyranosides into their iodoethyl derivatives, which then undergo substitution with the Williams' chiral glycine enolate equivalent. Deprotection and acetylation affords Boc-protected amino acids for peptide synthesis.

Syntheses of four unusual amino acids, constituents of cyclomarin A

The stereoselective syntheses of four unusual amino acids, constituents of cyclomarin A, are described. The protected N-methylhydroxyleucine 2 was synthesized using Evans’ asymmetric azide-transfer reaction. The unusual amino acid 3 was prepared via diastereoselective methylation of the l-aspartic acid derived lactone 13 . The stereoselective formation of threo-β-methoxyphenylalanine 4 was performed via aldol reaction using Schöllkopf's chiral glycine enolate. The synthesis of N-reverse prenylated tryptophane 5 was achieved by the AQN ligand-promoted Sharpless regioreversed asymmetric aminohydroxylation protocol.

ChemInform Abstract: Preparation of α‐Amino‐carboxylic Acid Derivatives via Diastereoselective Reactions of Glycine Enolate Equivalents.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Preparation of α-amino-carboxylic acid derivatives via diastereoselective reactions of glycine enolate equivalents

Protected glycine analogues tethered to an imidazolidinone auxiliary undergo diastereoselective alkylation and acylation reactions in moderate to good yields (9–91%) with high levels of stereocontrol (generally >95% de). Subsequent alkylation of these derivatives has been demonstrated for the production of non-racemic α,α-disubstituted amino acid precursors. Diastereoselective aldol reactions are also found to proceed with good yields and excellent stereocontrol (62–84%, 93–95% de). Chiral auxiliary cleavage and hydrogenolysis of these adducts affords the β-hydroxy-α-amino acid derivatives with no observed erosion of optical purity.

Highly enantioselective synthesis of a fluorescent amino acid

A high enantiomeric excess (>99.5%) synthesis of l-2-amino-3-(7-methoxy-4-coumaryl) propionic acid (l-Amp) is described. The two step synthesis route of this non-proteinogenic amino acid includes an oxazinone derivative as glycine enolate, which is alkylated with the fluorogenic group.

Syn-Selective boron mediated aldol condensations for the asymmetric synthesis of β-hydroxy-α-amino acids

Imidazolidinone-bound glycine enolate derivatives have been shown to undergo aldol condensation with aromatic and aliphatic aldehydes in good yields and with excellent stereocontrol (62–84%, 93–95% d.e.). Removal of the pendant imidazolidinone auxiliary and hydrogenolysis affords the β-hydroxy-α-amino acid derivatives.

Stereoselective Aldol Addition of a Chiral Glycine Enolate Synthon to Heteroaromatic Aldehydes

Stereoselective Aldol Addition of a Chiral Glycine Enolate Synthon to Heteroaromatic Aldehydes

Enantiospecific synthesis of (+)-ribasine

The alkaloid (+)-ribasine was synthesized by stereocontrolled addition of substituted α-lithium- o-toluate 6d to enantiomerically pure ( R)- N-(9-phenylfluoren-9-yl)-2-amino-5,6-(methylenedioxy)indan-1-one [(+)- 5]. Aminoindanone (+)- 5 was prepared from amino acid (−)- 15 obtained by diastereoselective alkylation of a chiral glycine enolate synthon.

ChemInform Abstract: Practical Synthesis of α‐Amino Acids Using cis‐Aminoindanol Derived Hippuric Acid Amide as a Glycine Enolate Equivalent.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Practical synthesis of α-amino acids using cis-aminoindanol derived hippuric acid amide as a glycine enolate equivalent

Abstract The use of cis -aminoindanol as a chiral auxiliary for asymmetric synthesis of α-amino acids is described. Alkylation of the chirally modified glycine enolate 2 with a number of alkyl halides in the presence of lithium chloride gave the corresponding alkylated product in 90 ∼ 99% diastereoselectivity.

ChemInform Abstract: Chemoenzymatic Synthesis of Unnatural Amino Acids via Modified Claisen Rearrangement of Glycine Enolates. Approach to Morphine Synthesis.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Chemoenzymatic Synthesis of Unnatural Amino Acids via Modified Claisen Rearrangement of Glycine Enolates. Approach to Morphine Synthesis

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTChemoenzymatic Synthesis of Unnatural Amino Acids via Modified Claisen Rearrangement of Glycine Enolates. Approach to Morphine SynthesisDavid Gonzalez, Valeria Schapiro, Gustavo Seoane, Tomas Hudlicky, and Khalil AbboudView Author Information Department of Chemistry, University of Florida, Gainesville, Florida 32611, and Facultad de Química, Universidad de la República, Gral. Flores 2124, Montevideo, Uruguay Cite this: J. Org. Chem. 1997, 62, 5, 1194–1195Publication Date (Web):March 7, 1997Publication History Received11 December 1996Published online7 March 1997Published inissue 1 March 1997https://doi.org/10.1021/jo962315wCopyright © 1997 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views573Altmetric-Citations18LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (116 KB) Get e-AlertsSupporting Info (2)»Supporting Information Supporting Information SUBJECTS:Enolates,Monomers,Peptides and proteins,Rearrangement,Transition states Get e-Alerts

Asymmetric synthesis of fluorinated l-tyrosine and [formula omitted

A convenient asymmetric synthesis of (2 S)-2-amino-3-(2-fluoro-5-hydroxyphenyl) propanoic acid, (2 S)-2-amino-3-(4-fluoro-3-hydroxyphenyl) propanoic acid and (2 S)-2-amino-3-(2-fluoro-4-hydroxyphenyl) propanoic acid is described. Key steps include the synthesis of the benzyl bromides, the alkylation of the glycine enolate derivative (( S)-Boc-BMI) and the hydrolysis of the alkylated Boc-BMI.

Synthesis of a 14-Membered Cyclic Peptide Model of the CFG Rings of Ristocetin A and Observations on Atropdiastereoisomerism

Two routes for the synthesis of a 14-membered heterodetic cyclic peptide as a model for the CFG ring system of the antibiotic ristocetin A (2) are described. The key aryl ether bonds for this molecule were constructed by using the reaction of phenoxides from (hydroxyaryl)glycine derivatives with tricarbonyl(3-methoxy-2-methylchlorobenzene)manganese hexafluorophosphate (11). This coupling reaction can be performed in the presence of protected amino acids and dipeptides without racemization of the sensitive arylglycine. Stereoselective introduction of the F-ring glycine side chain was accomplished by reaction of the aryl ether manganese complexes with Schollkopf's bislactim glycine enolate equivalent. The product(s) from this reaction were demetalated and aromatized by treatment with N-bromosuccinimide. Deprotection of tha aromatized compounds followed by cycloamidation furnished two atrodiastereomeric cyclic peptides corresponding to the target molecule, the structures of which were assigned on the basis of 2D-NMR NOESY experiments coupled with molecular modeling. One of the product molecules corresponds closely to the structure that has been proposed for the CFG ring system of ristocetin, except for the orientation of the w 3 amide group

Diastereoselective Synthesis of Glycos-3-yl-α-amino Easters

Abstract We report here the diastereoselective synthesis of (2S, 3′R)-(α-D-allofuranos-3-yl) t-butyl glycinate by the condensation of a glycine enolate on the carbonyl function of α-D-ribohexofuranos-3-ulose 2.