Ester Dienolate Research Articles

Stereoselective Synthesis of a Protected Side Chain of Meliponamycin A.

The Matteson homologation was found to be a versatile tool for the construction of the linear polyketide side chain of meliponamycin and related compounds in only four steps. The ester dienolate version of this reaction allowed the introduction of the unsaturated ester moiety in a highly stereoselective fashion. Boronate oxidation/deoxygenation and Sharpless dihydroxylation are additional key steps in the stereoselective construction of this highly functionalized tetrahydropyran ring system, which is characteristic of this substance class.

A Straightforward Synthesis of Polyketides via Ester Dienolate Matteson Homologation.

Application of ester dienolates as nucleophiles in Matteson homologations allows for the stereoselective synthesis of highly substituted α,β‐unsaturated δ‐hydroxy carboxyl acids, structural motifs widespread found in polyketide natural products. The protocol is rather flexible and permits the introduction of substituents and functionalities also at those positions which are not accessible by the commonly used aldol reaction. Therefore, this ester dienolate Matteson approach is an interesting alternative to the “classical” polyketide syntheses.

Ester Dienolate [2,3]-Wittig Rearrangement in Natural Product Synthesis: Diastereoselective Total Synthesis of the Triester of Viridiofungin A, A2, and A4

[structure: see text] An ester dienolate [2,3]-Wittig rearrangement was utilized to access the alkylated citric acid skeleton 6 that is characteristic for the viridiofungins and other members of the alkyl citrate family of secondary natural products. The [2,3]-sigmatropic rearrangement of (Z,Z)-15 provided the rearrangement product (+/-)-syn-16 in moderate yield and with very good diastereoselectivity. A Julia-Kocienski olefination efficiently served to connect the polar head (+/-)-syn-26 with the lipophilic tail (32a-c) of the viridiofungins. Amide formation between the racemic viridiofungin precursors 35a-c and the enantiomerically pure amino acid L-tyrosine methyl ester followed by preparative reversed-phase HPLC provided the isopropyl dimethyl ester of viridiofungin A ((+)-39a), A2 ((+)-39b), and A4 ((+)-39c) as well as the nonnatural diastereomers (-)-38a-c.

Total synthesis of (3 S,4 S,2′ S)- and (3 R,4 R,2′ S)-viridiofungin A triester

The total synthesis of an alkylcitrate secondary metabolite from the fungi Trichoderma viride is described. An ester dienolate [2,3]-Wittig rearrangement and a S. Julia-Kocienski olefination served as key C/C-connecting transformations. The highly convergent synthesis consists of a longest linear sequence of 17 steps.

The Ester Dienolate [2,3]‐Wittig Rearrangement — Development, Opportunities, and Limitations.

AbstractFor Abstract see ChemInform Abstract in Full Text.

The Ester Dienolate [2,3]-WittigRearrangement - Development, Opportunities, andLimitations

The account summarizes the development of the ester dienolate [2,3]-Wittig rearrangement as a versatile synthetic tool for the construction of highly substituted 3-alkoxycarbonyl-3-hydroxy-substituted 1,5-hexadienes. Furthermore, the account provides an insight into a novel sequential pericyclic reaction employing the 1,5-hexadienes accessible through the ester dienolate [2,3]-Wittig rearrangement.

ChemInform Abstract: Sequencing Pericyclic Reactions: The Ester Dienolate [2,3]‐Wittig/Oxy‐Cope Rearrangement/Carbonyl Ene Reaction, a New Access to Substituted Carbocycles.

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.

Sequencing Pericyclic Reactions: The Ester Dienolate [2,3]-Wittig/Oxy-Cope Rearrangement/Carbonyl Ene Reaction, a New Access to Substituted Carbocycles

The sequential ester dienolate [2,3]-Wittig/oxy-Cope rearrangement/carbonyl ene reaction has been investigated. Acyclic α,β-unsaturated α-allyloxy-substituted esters 1a−j were transformed into cyclopentane- or cyclohexanecarboxylates 6a−f and 7a−7d. This study presents a domino ester dienolate [2,3]-Wittig/oxy-Cope rearrangement or a domino oxy-Cope rearrangement/carbonyl ene reaction, depending on the substrate structure. The thermal intramolecular type-I carbonyl ene reaction as the terminating ring-closing reaction proceeds with high simple diastereoselectivity, but low induced diastereoselectivity. The corresponding type-II ene reaction afforded the cyclohexanecarboxylates 7a−d in high yield with complete simple and induced diastereoselectivity. Unfortunately, an attempted auxiliary-controlled enantioselective sequence was inefficient.

The Sequential Ester Dienolate [2,3]-Wittig/3-oxy-Cope Rearrangement. New Access to Substituted α-Keto Esters

The Sequential Ester Dienolate [2,3]-Wittig/3-oxy-Cope Rearrangement. New Access to Substituted α-Keto Esters

The ester dienolate [2,3]-Wittig rearrangement. Diastereoselective synthesis of 2,3-dialkenyl-substituted 2-hydroxy-γ-lactones

The ester dienolate [2,3]-Wittig rearrangement proceeds with high yield and anti/syn diastereoselection to afford 3-alkoxycarbonyl-3-hydroxy-substituted 1,5-hexadienes. No donor solvent or metal salt additive was necessary to trigger the rearrangement. The rearrangement product was transformed to diastereomerically pure 2,3-dialkenyl-substituted γ-lactones. A transition state picture was proposed based on previously reported transition state models for enolate [2,3]-Wittig rearrangements.

ChemInform Abstract: Stereoselective Ester Dienolate Carroll Rearrangement: A New Approach to the Prelog‐Djerassi Lactone Framework.

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.

Stereoselective ester dienolate Carroll rearrangement: A new approach to the Prelog-Djerassi lactone framework

Abstract The stereoselective ester dienolate Carroll rearrangement of (E) and (Z)-allylic β-ketoesters has been studied and found to be a new attractive approach to the synthesis of the Prelog-Djerassi lactone and related compounds. The synthesis of the optically active lactone (−)-(2R, 3R, 4R, 6S)-1 as well as the formal synthesis of its natural occurring isomer are described.

The preparation of ethyl and isopropyl dienol ethers and dienol pivalate esters from Hagemann's ester and its t-butyl analogue, and the reactions of the derived ester dienolates with electrophiles

The preparation of ethyl 4-ethoxy-2-methylcyclohexa-1,3-diene-1-carboxyate, ethyl 4-isopropoxy- 2-methylcyclohexa-1,3-diene-1-carboxylate, t-butyl 4-isopropoxy-2-methylcyclohexa-1,3-diene-1- carboxylate, ethyl 4-(t-butylcarbonyloxy)-2-methylcyclohexa-1,3-diene-1-carboxylate, and t-butyI 4-(t-butylcarbonyloxy)-2-methylcyclohexa-1,3-diene-1-carboxylate from Hagemann's ester and its t-butyl analogue in the presence of diethyl or diisopropyl sulfates and sodium hydride in dimethyl sulfoxide, or pivaloyl chloride and N,N,N',N'-tetramethylethylenediamine in tetrahydrofuran is described. The foregoing dienol ethers and esters are smoothly deprotonated by lithium diisopropyl- amide in tetrahydrofuran at -78" to give the corresponding ester dienolates, which react regio- specifically with a number of electrophiles, either a or y to the alkoxycarbonyl group of the dienol ether or ester. A number of the products, which are generally obtained in good yields, have been hydrolysed to Hagemann's ester derivatives substituted exclusively at C1.

Stereochemistry of ester dienolate anions. Stereoselective route to botryodiplodin

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStereochemistry of ester dienolate anions. Stereoselective route to botryodiplodinStephen R. Wilson and Richard S. MyersCite this: J. Org. Chem. 1975, 40, 22, 3309–3311Publication Date (Print):October 1, 1975Publication History Published online1 May 2002Published inissue 1 October 1975https://doi.org/10.1021/jo00910a043RIGHTS & PERMISSIONSArticle Views144Altmetric-Citations42LEARN 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 PDF (376 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Regioselectivity in the alkylation of lithium and copper ester dienolates. Allylic transposition associated with .gamma.-alkylation of copper dienolates

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRegioselectivity in the alkylation of lithium and copper ester dienolates. Allylic transposition associated with .gamma.-alkylation of copper dienolatesJohn A. Katzenellenbogen and Ann L. CrumrineCite this: J. Am. Chem. Soc. 1974, 96, 17, 5662–5663Publication Date (Print):August 1, 1974Publication History Published online1 May 2002Published inissue 1 August 1974https://doi.org/10.1021/ja00824a104RIGHTS & PERMISSIONSArticle Views333Altmetric-Citations34LEARN 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 PDF (299 KB) Get e-Alerts Get e-Alerts