Condensation Of Ketones Research Articles

Novel mercuric triflate-catalyzed condensation of ketones and homoallyl alcohols

Novel condensation of ketones with homoallyl alcohols catalyzed by Hg(OTf) 2 has been developed, generating a 6-membered ring ether alcohol, bisether, and olefins. The reaction is initiated b hemiacetal formation, and cyclization of the resulting oxonium cation provides the 6-membered ring carbocation as a common intermediate. Thus, it is a catalytic Prins-type condensation of non-activated homoallyl alcohols and ordinary ketones.

ChemInform Abstract: Asymmetric Darzens Condensation of Ketones with α‐Chloroacetates by Means of (‐)‐8‐Phenylmenthyl Auxiliary.

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Syntheses of Knerachlin A and Knerachlin B

The first total syntheses of knerachlin A and knerachlin B are described, starting from 2,4,6-trihydroxyacetophenone and 2,6-dihydroxyacetophenone, respectively. The key step in the synthesis is the condensation of ketone 5 with cinnamaldehyde.

Synthetic Application of Et3GeNa/LnCl3: Stereoselective Aldol Condensation of Ketones and Amides

Synthetic Application of Et3GeNa/LnCl3: Stereoselective Aldol Condensation of Ketones and Amides

Asymmetric darzens condensation of ketones with α-chloroacetates by means of (–)-8-phenylmenthyl auxiliary

The Darzens condensation of symmetric and unsymmetric ketones with (–)-8-phenylmenthyl α-chloroacetate diastereoselectively affords glycidic esters in 77–94% de; the stereochemistry [(2R,3R) configuration] of the product is understandable in terms of π–π interaction in the open transition state model.

A Simple One-Pot Synthesis of Functionalized Ketimines from Ketones and Amine Hydrochloride Salts

Abstract Functionalized ketimines of the general formula RR′C(=NCH2Y) [R and R′ = Ph, alkyl; Y = CN (1), CH2Cl (2), COOMe (3)] have been prepared by the condensation of ketones with the corresponding primary amine hydrochloride salts [NH2CH2Cl.HCl (4), NH2CH2CH2Cl.HCL (5) and NH2CH2COOMe HCl (6), respectively]. The reported reaction proceeds mildly in a single step without the need of a previous isolation of the free amine from its salt. N,N-Dimethylformamide (DMF) is used as the solvent and TiCl4 as the drying agent.

Synthesis of α-amidoketones. An application of the multi-hetero cope rearrangement

Condensation of ketone derived nitrones with N-methylcarboximidoyl chloride affords after hydrolytic workup α-amidoketones. The results are interpreted in terms of the formation of an intermediate capable of undergoing a facile [3,3] sigmatropic rearrangement. Aldehyde derived nitrones form imides via a [3+2] cycloaddition reaction.

Application of solid base catalysts in the preparation of prepolymers by condensation of ketones and malononitrile

Solid base catalysts such as zeolites, sepiolites and hydrotalcites have been used to prepare prepolymers of malononitrile with cyclohexanone, benzophenone, and p-amino acetophenone which are of interest for preparing living polymers. The reactivity depends on both the catalyst and the nature of the ketone. Among the catalysts studied, hydrotalcites are the most active, followed by cesium-exchanged sepiolites. High selectivities and good yields have been obtained with these two solid base catalysts. It is proposed that the controlling step for these condensation reactions is not the formation of the carbanion, but the addition of the carbanion to the carbonyl group.

Synthesis and structure of strained polycyclic cyclobutane-containing derivatives

The compounds cis,anti,cis-8-methoxytricyclo[6.3.0.-0 2,7 ]undecan-2,3-diol and cis,anti,cis-tricyclo[6.5.0.0 2.7 ]-tridec-6-en-13-spiro-2'-[1,3]dioxan-1-ol were obtained by condensation of ketone enolates with cyclohexadiene generated in situ from 1-chlorocyclohexene. X-ray structure analysis established the conformations of the polycyclic systems, the stereochemistry at the ring junctions and the deformations caused by fusion of the rings. The results of the refinements on F and F 2 are compared

Trimethylsilylcyanid als Umpolungsreagens, XXIII. Umpolungsprodukte aus α,β1‐ungesättigten Aldehyden mit α,β1‐ungesättigten Carbonyl‐Verbindungen: Folgereaktionen

Trimethylsilyl Cyanide – A Reagent for Umpolung, XXIII[1]. – Products from Umpolung of α,β1‐Unsaturated Aldehydes and α,β1‐Unsaturated Carbonyl Compounds: Consecutive ReactionsThe unsaturated nitrile 1 is transformed by TiCl4 into chloronitrile 2, whereas reaction with [BzNMe3]+F− and treatment with acids yields cyanocyclopentenone 4. Removal of the umpolung groups from 1 and 5–8 by [BzNMe3]F− results in the unsaturated 1,4‐diketones 9–13 only if the cyanide ions formed are prevented by ZnO from adding to the double bond. Condensation of ketones 9 and 11–13 with tBuOK yields cyclopentenones 14–18 with conjugated vinylic groups. In the presence of [BzNMe3H]+F− α1‐cyano enol silyl ethers 22–24 are smoothly converted in methanol into ϵ1‐oxo‐carboxylic esters 19–21, whereas in pure methanol α1‐hydroxycyclopentanecarboxylic esters 25–27 are produced in high yied.

Efficient Synthesis of New Benzocyclobutenic Phenethylamines

Abstract New benzocyclobutenic phenethylamines were easily obtained from simple starting materials by arynic condensations of ketones enolates.

Synthesis of cyclo-bis[7α, 12α-diacetoxy-3β-dicyanomethyl-3α-(4-methylenephenyl)cholanamide]; a cholaphane with reduced flexibility and externally-directed functionality

A second ‘cholaphane’ framework is manifested in the title compound 8, which has been prepared from methyl 3α,7α, 12α-triacetoxycholanoate 9 in 23% overall yield. The synthesis involves the Knoevenagel condensation of ketone 11 with malononitrile to give dicyanomethylene derivative 12, equatorialselective addition to the latter of an organocuprate derived from aryl bromide 15, conversion of the resulting adduct into amino acid 22, and cyclodimerisation. The framework of 8 has less conformational freedom and a better-defined cavity than the ‘first-generation’ cholaphanes 2, and also bears externallydirected functionality.

Investigations of the tetrachlorosilane-ethanol induced self condensations of ketones.

Silicon tetrachloride-ethanol induced self condensation of ketones to yield tri- or hexasubstituted benzenes, can be diverted in a variety of ways, dependent on the steric hindrance of the ketone. A number of examples of cyclic ketone condensations are given, and the surprising result from condensation of propiophenone as compared with acetophenone is presented.

Conformational dichotomy and pyramidalized carbonyl groups in zinc aldolate chelates obtained from aldol condensations of ketones: crystallographic characterization of {[(Me3Si)2N]Zn[.mu.,.eta.2-OCR1(CH2R2)CHR2C(O)R1]}2

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConformational dichotomy and pyramidalized carbonyl groups in zinc aldolate chelates obtained from aldol condensations of ketones: crystallographic characterization of {[(Me3Si)2N]Zn[.mu.,.eta.2-OCR1(CH2R2)CHR2C(O)R1]}2Subhash C. Goel, Michael Y. Chiang, and William E. BuhroCite this: J. Am. Chem. Soc. 1991, 113, 18, 7069–7071Publication Date (Print):August 1, 1991Publication History Published online1 May 2002Published inissue 1 August 1991https://doi.org/10.1021/ja00018a072RIGHTS & PERMISSIONSArticle Views82Altmetric-Citations11LEARN 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 (1 MB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

ChemInform Abstract: Aldol Condensation of Ketones Promoted by Sterically Crowded Aryloxide Compounds of Aluminum.

AbstractThe mixture (III)/(IV) crystallizes in P21 with Z=2.

Aldol condensation of ketones promoted by sterically crowded aryloxy compounds of aluminum

Aldolisation de O=C(He) t Bu, O=C(Et)Ph, O=CEt 2 en utilisant AlEt x (BHT) 3−x (x=1, 2) BHT=2,6-di-t-butyl-4-methylphenol

Heteroadamantanes and their derivatives 11. Synthesis of 3,6-diazahomoadamantan-9-one and its derivatives with substituents in the angular positions

The condensation of ketones with tetramethylenediethylenediamine led to the isolation of 3,6-diazahomoadamantan-9-one and its derivatives with substituents in the angular positions; their structure was confirmed by the data of the IR, PMR, and mass spectra.

Arynic Condensation of Ketone Enolates XX. New Access To Polycyclic Phenylethanolamines

Abstract A new preparation of two kinds of potentially biologically active phenylethanolamines is described. The basic reaction of these syntheses is arynic condensation of ketone enolates in the presence of Complex Bases.

A Facile Preparation of Highly Substituted ß-Ketoamides

Abstract A procedure is described for the preparation of s-ketoamides by the condensation of ketones and isocyanates under mild conditions.

Arynic condensation of ketone enolates 18 1: Efficient access to benzocyclenones and polycyclic indanone derivatives

It is shown that benzocyclobutenols 1 are excellent starting materials for the obtention of polycyclic aromatic ketones. Thus under basic conditions they lead to benzocyclenedione mono ketals which may be hydrolyzed into the corresponding benzocyclenediones. Under acidic conditions, a transposition takes place leading to indanone derivatives. The mechanism of this transposition is discussed.