Vinyl Ketene Research Articles

Cyclobutanone formation via in situ generated vinyl ketene complexes of chromium

La reaction du chrome (methoxymethylmethylene) pentacarbonyle avec l'heptene-1yne-6 dans l'acetonitrile conduit aux deux isomeres de la bicyclo [3.2.0] heptanone-6 substitues en α du groupe carbonyle par un groupe methoxy-2propenyl(E) ou (Z)

Vinylketene: VI. [2+ 2]cycloaddition an silylvinylketene: Konkurrierende addition von inaminen an die keten-CC- und die keten-CO-bindung

Alcohols and amines react with silyl vinyl ketenes to give esters and amides. Ynamines undergo a primary competing addition across the ketene CC and the ketene CO bond. A sequence of cycloaddition and ring-opening reactions finally leads to bicyclo[3.1.0]hexenones, cyclohexadienones and allenic amides.

Proton and carbon-13 NMR of vinyl ketene and its dimerization by [4 + 2] cycloaddition. Synthesis of sibirinone and bicyclo[4.2.1]nona-3,7-diene-2-one

Bei der Vakuumpyrolyse des Saureanhydrids (I) entsteht Vinylketen (IV) im Gemisch mit Crotonsaure (II) und Propin (III).

ChemInform Abstract: VINYL KETENES. 3. ADDITION OF YNAMINES TO VINYLKETENES

Chemischer InformationsdienstVolume 12, Issue 28 Organoelement Compounds ChemInform Abstract: VINYL KETENES. 3. ADDITION OF YNAMINES TO VINYLKETENES K. H. + DOETZ, K. H. + DOETZSearch for more papers by this authorB. TRENKLE, B. TRENKLESearch for more papers by this authorU. SCHUBERT, U. SCHUBERTSearch for more papers by this author K. H. + DOETZ, K. H. + DOETZSearch for more papers by this authorB. TRENKLE, B. TRENKLESearch for more papers by this authorU. SCHUBERT, U. SCHUBERTSearch for more papers by this author First published: July 14, 1981 https://doi.org/10.1002/chin.198128263Read 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 onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume12, Issue28July 14, 1981 RelatedInformation

Anthracyclines. II - regiospecific synthesis of 6-deoxyanthracycline intermediates

Resume Reaction of vinyl ketene acetal 4 , easily prepared from diethyl 4-oxopimelate, with various naphthoquinones affords a short and regiospecific route to tetracyclic ketones, key intermediates for the further synthesis of 6-deoxyanthracylines.

ChemInform Abstract: PREPARATION AND THE MICROWAVE AND INFRARED SPECTRA OF VINYL KETENE

Chemischer InformationsdienstVolume 11, Issue 11 Physical Organic Chemistry ChemInform Abstract: PREPARATION AND THE MICROWAVE AND INFRARED SPECTRA OF VINYL KETENE E. BJARNOV, E. BJARNOVSearch for more papers by this author E. BJARNOV, E. BJARNOVSearch for more papers by this author First published: March 18, 1980 https://doi.org/10.1002/chin.198011058AboutPDF 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 onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume11, Issue11March 18, 1980 RelatedInformation

Preparation and the Microwave and Infrared Spectra of Vinyl Ketene

Vinyl ketene (1,3-butadiene-1-one) has been synthesized by vacuum pyrolysis of 3-butenoic 2-butenoic anhydride. The microwave and infrared spectra of vinyl ketene in the gas phase at room temperature have been studied. The trans-rotamer has been identified, and the spectroscopic constants were found to be Ã= 39571(48) MHz, B̃ = 2392.9252(28) MHz, C̃ = 2256.0089(28) MHz, ⊿j = 0.414(31) kHz, and ⊿JK = - 34.694(92) kHz. The electrical dipole moment was found to be 0.987(23) D with μa = 0.865(14) D and μb = 0.475(41) D. A tentative assignment has been made for 17 of the 21 normal modes of vibration

Umpolung of the Reactivity of Carbonyl Compounds Through Sulfur-Containing Reagents

The synthetic usefulness of the umpolung of the reactivity of carbonyl compounds by reaction of sulfur-containing reagents is discussed. Firstly, hydrolysis and other reactions of S, S-acetals (mainly 1,3-dithianes) and vinyl sulfides are described. The second part is concerned with the reactions of other sulfur-containing reagents such as derivatives of vinyl sulfides, ketene S,S-acetals and derivatives, etc. Finally the applications of the methods to the syntheses of natural products are briefly mentioned. 1. Introduction 2. Hydrolysis of S,S-Acetal and Vinyl Sulfide Derivatives and other Desulfurization Reactions 2.1. Acidic Hydrolysis and Transacetalization 2.2. The Transition Metal-Induced Hydrolysis 2.3. Oxidative and Alkylative Hydrolysis of S,S-Acetals 2.4. Oxidative Solvolysis of Vinyl Sulfides and Ketene S, S-Acetals 2.5. Reductive Desulfurizations 3. Reactions of S,S-Acetal Derivatives (E1-Type) 3.1. Metallated 1,3-Dithianes 3.2. Use of Metal Derivatives of S,S-Acetals other than 1,3-Dithianes 3.3. S,S-AcetalS-Oxides: Alkylation, Cycloalkylation, Arylation, Hydroxyalkylation, and Acylation Reactions 3.4. Reactions of Metallated S,S-Acetals with Heteroelectrophiles 3.5. Michael-Addition of S,S-Acetal Metal Derivatives 4. Miscellaneous Sulfur-Containing Reagents 4.1. Nucleophilic Acylations with Diheterosubstituted Anionic Reagents (XYRC-) 4.2. Reactions of (RS)3C- -Reagents and of Thioformyl Anions with Electrophiles 4.3. Umpolung of Carbonyl Reactivity with α-Phenylsulfonyl Nucleophiles and with Sulfur-Substituted Cyclopropanes 5. The Use of Vinyl Sulfides and Ketene S,S-Acetal Derivatives (E1-, N2--, N4-Type Reactions) 5.1. Generation and E1-Reactions of α-Lithiovinyl Sulfides 5.2. Derivatives of Ketene S, S-Acetals 5.3. Survey of Useful Transformations through Vinyl Sulfides and Ketene S, S-Acetals 6. Applications of Sulfur-Substituted Allylic Anions (E3-, E5-Type) 7. Natural Product Synthesis 7.1. 1,4-Diketone Synthesis: Access to Jasmonoids, Rethrolonoids, and Prostanoids 7.2. Use of 2-Lithio-1,3-dithianes in Carbohydrate Synthesis 7.3. Other Natural Product Syntheses

Synthesen von 2‐Pyronen aus α, β‐ungesättigten Säurechloriden und tertiären Aminen

AbstractA new synthesis of 2‐pyrones has been developed. Two molecules of α, β‐unsaturated acid chlorides (8, 12 and 18) condense, with loss of two molecules hydrogen chloride, to pairs of substituted 2‐pyrones (9 and 10, 13 and 14, 19 and 20) when treated with triethyl amine in chloroform or methylene chloride at room temperature. In the case of 18, two additional products were obtained, namely the resorcinol derivative 21 and traces of the 1, 3‐cyclobutanedione derivative 22. Under the same conditions the α, β‐unsaturated acid chlorides 8, 15, 18 and 41 were condensed with trichloroacetyl chloride to give 6‐trichloromethyl‐2‐pyrones (42, 43, 44 and 46). These 2‐pyrones are valuable intermediates for the synthesis of 6‐carboxy‐2‐pyrones and 6‐methyl‐2‐pyrones.A methyl group in β‐position of the α, β‐unsaturated acid chloride appears to be essential for the described condensations, for the acid chlorides 16 and 17 did not yield defined products and the acid chloride 40 reacted with trichloroacetyl chloride in a very low yield. It is considered that the described reactions proceed via the 1, 4‐addition of an acid chloride to a vinyl ketene or through the acylation of an intermediate anion by an acyl derivative as outlined in reaction scheme 1. The structures of the 2‐pyrones were confirmed by their spectroscopic properties, summarized in table 3, and by some of their chemical transformations.