Cycloaddition Of Ketenes Research Articles

ChemInform Abstract: Intramolecular Ketene Cycloadditions

ChemInformVolume 18, Issue 2 Reviews ChemInform Abstract: Intramolecular Ketene Cycloadditions H.-U. REISSIG, H.-U. REISSIG D-8700 WuerzburgSearch for more papers by this author H.-U. REISSIG, H.-U. REISSIG D-8700 WuerzburgSearch for more papers by this author First published: January 13, 1987 https://doi.org/10.1002/chin.198702353Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume18, Issue2January 13, 1987 RelatedInformation

Novel and effective routes to optically pure amino acids, dipeptides, and their derivatives viaβ-lactams obtained through asymmetric cycloaddition

Optically pure dipeptides bearing aromatic amino acid residues were synthesized via homochiral (optically pure)β-lactams which were obtained through asymmetric cycloadditions of homochiral ketenes to homochiral imines.

Stereochemistry and ring opening of a carbocyclic analogue of a 1-oxapenam

The cycloaddition of succinimido ketene to 2,3-dihydrofuran yields P- exo -succinimido bicyclo [3.2.0] 2-oxoheptan-6-one. This unusual stereochemistry is confirmed by 1H NMR and X-ray crystallography. The cyclobutanone product undergoes ring opening in concentrated hydrochloric acid to give 1-succinimido-5-chloro-2-pentanone.

Fused azetidinones from 2-keto-dihydropyrimidines.

Cycloaddition of ketenes to 2-keto dihydropyrimidines give the title compounds. These constitute a new kind of cephalosporins keto-aza analogs.

ChemInform Abstract: Solvolysen von 4‐Alkylidenbicyclo[3.2.0]hept‐2‐en‐6‐olen. Synthese von 1‐Vinylfulvenen und 8,8‐Diphenylheptafulven.

AbstractBei Reduktionen der Bicyclo[3.2.0]heptenone (I) bilden sich trennbare Gemische von endo‐/exo‐Alkoholen des Typs (II)/(III), die der Solvolysebedingung A) unterworfen werden.

Solvolysen von 4‐Alkylidenbicyclo[3.2.0]hept‐2‐en‐6‐olen. Synthese von 1‐Vinylfulvenen und 8,8‐Diphenylheptafulven

Solvolysis of 4‐Alkydenbicyclo[3.2.0]hept‐2‐en‐6‐oles. Synthesis of 1‐Vinylfulvenes and 8,8‐DiphenylheptafulveneFour 4‐alkylidenebicyclo[3.2.0]hept‐2‐en‐6‐ones 2–5, obtained via ketene cycloaddition to fulvenes, were reduced to separated mixtures of the ‘endo’ ‐alcohols ‘endo’‐6 to ‘endo’‐9 (68–73%) and ‘exo’‐6 to ‘exo’‐9 (3–20%). Treatment of some of these alcohols with (CF3SO2)2O in CH2Cl2/pyridine caused a spontaneous solvolysis to yield unsaturated 7‐membered rings as pyridinium triflates 10–12 or 1‐vinylfulvenes 13 and 14, a new class of reactive tetraenes: Both ‘endo’‐9 and ‘exo’‐9, having two methyl groups at C(7), were converted into the vinylfulvene 13 (≈ 80%). The alcohols with two H‐atoms at C(7) exhibited a stereochemically controlled reaction selectivity, inasmuch as ‘endo’‐6 to ‘endo’‐8 afforded only the corresponding 7‐membered‐ring pyridinium salts 10–12 (66–79%), while ‘exo’‐6 produced only the vinylfulvene 14 (77%). A stereoelectronic control argument explains the C(1), C(5)‐bond cleavage with ‘endo’‐B and ‘endo’–6‐‘endo’‐8, as well as the C(1), C(7)‐bond cleavage with ‘exo’‐B, ‘exo’‐6, and with both ‘endo’‐ and ‘exo’‐9. Thermolysis (120°) of the pyridinium triflates 10 and 11 yielded the 3‐isopropenyl‐cycloheptatrienes 18 and 19, respectively (≈90%); similar conditions (145°) applied to the triflate 12 produced the doubly cyclized fluorene derivative 21 (60%). When the iodide 22 derived from the triflate 12 with Nal was heated in refluxing toluene, 8,8‐diphenylheptafulvene (23, 86%) was obtained.

Intramolecular [2+2] cycloadditions of ketenes and keteniminium salts to olefins

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIntramolecular [2+2] cycloadditions of ketenes and keteniminium salts to olefinsIstvan Marko, Bruno Ronsmans, Anne Marie Hesbain-Frisque, Stephane Dumas, Leon Ghosez, Beat Ernst, and Hans GreuterCite this: J. Am. Chem. Soc. 1985, 107, 7, 2192–2194Publication Date (Print):April 1, 1985Publication History Published online1 May 2002Published inissue 1 April 1985https://doi.org/10.1021/ja00293a073RIGHTS & PERMISSIONSArticle Views1829Altmetric-Citations97LEARN 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 (403 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Cycloadditions of ketenes with cyclic carbodiimides

AbstractThe cycloaddition of ketenes with cyclic carbodiimides yields β‐lactams in good to excellent yields. The cycloaddition of equal molar amounts of diphenyl‐, phenylethyl‐ and phenylketenes with cyclic carbodiimides produced a 1:1 cycloaddition product, the expected β‐lactams. However, the cycloaddition of a 2:1 molar ratio of diphenyl‐ and phenylketenes with 1,3‐diazacycloocta‐1,2‐diene respectively, gave the 2:1 cycloadducts, the tricyclodi‐β‐lactams. The cycloaddition of methylchloro‐ and dichloroketenes yielded β‐lactams that were very susceptible to hydrolysis to the N‐substituted cycloureas. A trapping experiment suggests that these reactions proceed through a stabilized dipolar intermediate.

ChemInform Abstract: Autocatalyzed Additions and Cycloadditions of Ketenes to Thiazoles.

AbstractDie Thiazole (I) und (V) reagieren mit den Ketenen (II) zu den Addukten (III), (IV) und (VI) bis (VIII).

Reactions of coordinated cyclic polyolefins. Regio- and stereo-specific cycloadditions of ketenes and tricarbonyl(η 4-polyene)iron complexes. Structural evidence for a concerted 2 + 2 mechanism

The cycloaddition of ketenes R 1R 2CCO (R 1 = Me, R 2 = Ph; R 1 = R 2 = Ph; R 1 = Ph, R 2 = p-tolyl) (III) and tricarbonyl(η 4-cycloheptatriene)iron (II) at room temperature gave regiospecifically the cyclobutanones IV, in which the carbonyl is bonded to the uncoordinated terminal of the conjugated triene. Tricarbonyl(η 4-cyclooctatetraene)iron, VI, similarly reacts with dipenylketene to give the regioisomeric cyclobutanone VIII. Single crystal X-ray analysis of tricarbonyl[(η-2,3,4,5)-9-methyl-9-phenylbicyclo[5.2.0]nonan-2,4-dien-8-one]iron (IVa) confirmed the presence of the phenyl group at the endo position, providing a stereochemical evidence for a concerted 2 s + 2 a cycloaddition mechanism. The adducts IV undergo cyclobutanone ring cleavage catalyzed by acid to give the isomeric ketones VII. The diaryl adducts (IVb and IVc) rearrange thermally to the σ,π-allylic complexes IX, which may also be obtained directly upon heating cycloheptatriene complex II and the diarylketenes.

Additions and cycloadditions of ketenes to 1,3-thiazole and its alkyl derivatives

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAdditions and cycloadditions of ketenes to 1,3-thiazole and its alkyl derivativesAlessandro Medici, Giancarlo Fantin, Marco Fogagnolo, Paola Pedrini, Alessandro Dondoni, and Giovanni Dario AndreettiCite this: J. Org. Chem. 1984, 49, 4, 590–596Publication Date (Print):February 1, 1984Publication History Published online1 May 2002Published inissue 1 February 1984https://doi.org/10.1021/jo00178a003RIGHTS & PERMISSIONSArticle Views320Altmetric-Citations29LEARN 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 (2 MB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Autocatalyzed Additions and Cycloadditions of Ketenes to Thiazoles

Autocatalyzed Additions and Cycloadditions of Ketenes to Thiazoles

The (4 + 2) cycloaddition of ketenes and .beta.-methoxy .alpha.,.beta.-unsaturated ketones: 2-pyranones

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe (4 + 2) cycloaddition of ketenes and .beta.-methoxy .alpha.,.beta.-unsaturated ketones: 2-pyranonesWilliam T. Brady and Michael O. AghoCite this: J. Org. Chem. 1983, 48, 26, 5337–5341Publication Date (Print):December 1, 1983Publication History Published online1 May 2002Published inissue 1 December 1983https://doi.org/10.1021/jo00174a034RIGHTS & PERMISSIONSArticle Views375Altmetric-Citations17LEARN 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 (650 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

β-Lactone as intermediate in the perkin reaction catalyzed by tertiary amines

The Perkin reaction catalyzed by tertiary amines is found to run not according to the aldol-type condensation mechanism but according to the mechanism in which the first stage is the formation and cycloaddition of ketene, yielding a β-lactone, which cleaves to the unsaturated acid.

Syntheses of σ-cyclobut-1-en-3-onyl complexes by cycloaddition of ketenes to some transition metal alkynyl complexes

Reactions of ketenes (R 1R 2CCO) with (η 5-C 5H 5)Ni(PPh 3)CCR (I) and (η 5-C 5H 5)Fe(CO)(L)CCR (III, L = CO and PPh 3) give σ-cyclobut-1-en-3-onyl complexes, {(η 5-C 5H 5)Ni(PPh 3) CC(R)COC }R 1R 2 (VI) and (η 5-C 5H 5)Fe(CO)(L) CC(R)COC R 1R 2 (IX)}, (2 + 2) cycloaddition products, in good yields. The σ-cyclobutenonyl complexes also can be prepared by the reaction of I and III with acyl chlorides in the presence of triethylamine.

Additions and Corrections - Cyclo-additions of Ketenes with N-Fluorenylidenealklamine and -arylamine Oxides. Synthesis of Spirooxazolidinones and Spiroisoxazolidinones

Additions and Corrections - Cyclo-additions of Ketenes with N-Fluorenylidenealklamine and -arylamine Oxides. Synthesis of Spirooxazolidinones and Spiroisoxazolidinones

Spiro‐β‐lactame durch [2+2]‐Cycloaddition von Ketenen an Iminolactone

Spiro‐β‐lactams from [2+2]‐Cycloaddition of Ketenes to IminolactonesIminolactones (‘Isoimides’) derived from maleic anhydride and amines are shown to react with various ketenes in a [2+2]‐cycloaddition mode. Either preformed ketenes or the combination acid chloride/tertiary amine can be used as reagent. The reaction products have been assigned the spiro‐β‐lactam structure. Unsubstituted ketene is inert under the reaction conditions. It is possible to synthesize the spiro‐β‐lactams in a one‐pot procedure, starting from a mixture of maleic anhydride/amine and excess dialkylketene.

The Regioselectivity of the Cycloadditions of Ketenes with N-Alkyl- and N-Arylnitrones

The Regioselectivity of the Cycloadditions of Ketenes with N-Alkyl- and N-Arylnitrones

The effect of the trimethylsilylmethyl substituent on ketene cycloadditions

The effect of the trimethylsilylmethyl substituent on ketene cycloadditions

Cycloadditions. 12. The stereochemistry of cycloadditions of ketenes to unsymmetrical alkenes. Evidence for nonparallel transition states

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCycloadditions. 12. The stereochemistry of cycloadditions of ketenes to unsymmetrical alkenes. Evidence for nonparallel transition statesAlfred Hassner, Robert M. Cory, and Nelson SartorisCite this: J. Am. Chem. Soc. 1976, 98, 24, 7698–7704Publication Date (Print):November 1, 1976Publication History Published online1 May 2002Published inissue 1 November 1976https://doi.org/10.1021/ja00440a041RIGHTS & PERMISSIONSArticle Views350Altmetric-Citations22LEARN 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 (854 KB) Get e-Alerts Get e-Alerts