Allylic Isomerization Research Articles

Silylation de la tetraline et obtention d'une octaline monosiliciee

In the presence of lithium and in tetrahydrofuran as solvent, trimethylchlorisilane reacts with tetralin to give two new compounds, (I) and (II). The latter when refluxed with acetic acid leads to a new monosilylated olefin (III). The study of the desilylation mechanism leads to envisage an isomerization of allyl- into vinyl-silane.

Nonenzymic biogenetic-like cyclizations. Synthesis and cyclization of 4-(trans, trans-7,12-dimethyl-3,7-11-tridecatrienyl)-3-methyl-2-cyclohexen-1-ol and of its allylic isomer

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNonenzymic biogenetic-like cyclizations. Synthesis and cyclization of 4-(trans, trans-7,12-dimethyl-3,7-11-tridecatrienyl)-3-methyl-2-cyclohexen-1-ol and of its allylic isomerKathyln A. Parker and William S. JohnsonCite this: J. Am. Chem. Soc. 1974, 96, 8, 2556–2563Publication Date (Print):April 1, 1974Publication History Published online1 May 2002Published inissue 1 April 1974https://doi.org/10.1021/ja00815a039RIGHTS & PERMISSIONSArticle Views132Altmetric-Citations19LEARN 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-Alerts Get e-Alerts

Reactions of 2-chloro-NN-diethyl-1,1,2-trifluoroethylamine with alcohols. Part I. Preparation of 2β- and 4β-fluorogibberellins

The allylic 2β-hydroxy-group in esters of gibberellic acid (9) reacts with 2-chloro-NN-diethyl-1,1,2-trifluoro-ethylamine to give the corresponding esters of 2β-fluoro-4aα,7-dihydroxy-1β-methyl-8-methylenegibb-3-ene-1α, 10β-dicarboxylic acid 1,4a-lactone (5) and its allylic isomer 4β-fluoro-4aα,7-dihydroxy-1β-methyl-8-methylenegibb-2-ene-1α,10β-dicarboxylic acid 1,4a-lactone (14). The fluoro-acids (5) and (14) themselves were obtained by de-esterification of the corresponding p-bromophenacyl esters (7) and (15).

Cyclobutene derivatives from addition of α-halogeno electrophilic olefins to ynamines

Reaction of α-chloro- and α-bromoacrylonitrile, α-chloro- and α-bromoacrylic esters with diethylaminomethylacethylene and diethylaminophenylacetylene leads to cyclobutene derivatives of type 3 in high yields. Reaction of E- and Z-α-bromocrotononitrile takes place in a stereospecific way. A mechanistic scheme for a reaction sequence of cycloaddition and subsequent allylic isomerization is formulated on the basis of stereochemical and kinetic data. The halogen substituents of the cyclobutene derivatives are stereospecifically displaced by the OH or the OEt groups in solvolytic reactions, with retention of configuration. Methylenecyclobutene derivatives are obtained from the 3-methylcyclobutenes by elimination of hydrogen halide with potassium t-butoxide. Hydrolysis of the enamine function of the cyclobutenes leads to the corresponding cyclobutanones. The configurations of four pairs of cis-trans isomeric cyclobutenes have been established by 1H- and 13C-NMR spectroscopy.

15-Hydroxy-9-oxoprosta-11,13-dienoic acid as the product of a prostaglandin isomerase

The initial product of the interaction between prostaglandin A(1) and the prostaglandin isomerase of cat blood plasma has been isolated. By ultraviolet spectroscopy and mass spectrometry and from stability and chromatographic studies, the structure of the compound has been established as 15-hydroxy-9-oxoprosta-11,13-dienoic acid, an allylic isomer of prostaglandin A(1). The compound is unstable under mild alkaline conditions, isomerizing to prostaglandin B(1). The biological significance of the enzymatic isomerization of prostaglandin A(1) is discussed.

Continuous allylic isomerization of tertiary vinyl carbinols to compounds with varied odors

Continuous allylic isomerization of tertiary vinyl carbinols to compounds with varied odors

Investigations in the field of oxygen-containing heterocycles

In the presence of stannic chloride, 2,3-dichlorotetrahydrofuran adds to isoprene with the formation of 3-chloro-2-(4′-chloro-2′-methylbut-2′-enyl)tetrahydrofuran and to piperylene and bivinyl with the formation, predominantly, of 3-chloro-2-(4′-chloropent-2′-enyl)- and 3-chloro-2′-(4′-chlorobut-2′-enyl)tetrahydrofuran, respectively, with their allyl isomers. The amount of the latter was estimated from the NMR spectra at 20–30%.

A novel palladium(II) catalysed allylic isomerization

A palladium(II) catalysed allylic isomerization which apparently proceeds via a 1,3-acetoxonium ion type intermediate is reported.

Action de nucléophiles sur des sucres ramifiés cyanovinylidéniques: Addition conjuguée, stéréomutation, migration de doubles liaisons. Communication préliminaire

AbstractWhen treated with a series of nucleophiles cis‐3‐cyanomethylene‐3‐deocy‐1,2:5,6‐di‐O‐isopropylidene‐α‐D‐ribo‐hexofurannose (1) may yield its trans isomer, a product of allylic isomerization or a product of conjugate addition, depending on the nature of the nucleophile. The configuration of the starting material is also important as shown by the differences in reactivity between 1 and its trans‐xylo isomer 8.

Über eine ungewöhnliche Cyclisationsreaktion bei der Umsetzung von (+)‐Epoxy‐α‐dihydrojonon mit Hydrazinhydrat

Abstract(+)‐Epoxy‐α‐dihydroionone (2) is formed completely stereospecifically from (+)‐α‐ionone (1). Under the conditions of the Wharton reaction this epoxide gives the expected isomeric allyl alcohols 4 and 5 and, surprisingly, the bicyclic allyl alcohol 3. The structure and absolute configuration of the reaction products have been established. A common intermediate for the formation of compounds 3, 4 and 5 is probably the vinyl anion C.

Novel A-nor sterols: Synthesis and stereochemistry

A new and simple method of synthesis of A-nor sterols having a tertiary hydroxyl group allylic to an exocyclic methylene is described consisting of utilization of the Eschenmoser Fragmentation of αβ-epoxy ketones and the Stork Ring-closure of acetylenic ketones. 4 β,5 β-epoxycholestan-3-one gave 3-methylene-A-nor-cholestan-5 β-ol together with 3-methyl-A-nor-cholest-3-ene (III). The structure of the former was established by NMR, IR and by allylic isomerization. The stereochemistry at the 5 position was established by correlation with the diol and the minor epoxide obtained from III and to which configurations were assigned using NMR data. Exclusive formation of cis-hydrindane brings forth an unsuspected stereoselectivity in the Stork Ring-closure. The 17 β-hydroxyandrostane analogue was prepared via the pyranyl ether. With the hydroxyl unprotected the sole product in the Stork reduction was III (R = OH).

The mechanism of the acid-catalysed cyclization of labdadienols

The mechanism of the formic acid-catalysed cyclization of the allylic isomer (Ia) of manool to 14α-hibol formate is determined using deuterium labelling.

Correction. The Base-Catalyzed Isomerization of Allyl to Propenyl Sulfides.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCorrection. The Base-Catalyzed Isomerization of Allyl to Propenyl Sulfides.C Price and W SnyderCite this: J. Org. Chem. 1968, 33, 11, 4314Publication Date (Print):November 1, 1968Publication History Published online10 September 2003Published inissue 1 November 1968https://doi.org/10.1021/jo01275a600RIGHTS & PERMISSIONSArticle Views23Altmetric-Citations-LEARN 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 (172 KB) Get e-Alerts Get e-Alerts

The Stereochemistry of bicyclo[3.2.1]octane—XVI

Abstract The reductive debromination of exo-1-methyl-3,4-dibromobicyclo[3.2.1]octene-2 and its allylic isomer with LAH and LAD was shown to take place by an SN2′ mechanism. Moreover, it was established that the entering deuteride and leaving bromide ions were cis to each other.

The acid-catalysed hydrolysis of α-methylallyl acetate in aqueous solution

The kinetics of the acid-catalysed hydrolysis of a-methylallyl acetate in aqueous solution have been studied over the range 30-100�. Oxygen-18 tracer experiments reveal the mechanism to be solely Aac2 and the Arrhenius parameters are consistent with this conclusion. Crotyl alcohol is observed in the reaction products. The formation of rearranged alcohol is explained by allylic isomerization of the α-methylallyl alcohol produced by the hydrolysis.

The decomposition of gaseous chloroformates. Part IV. Allylic and benzyl chloroformates

The rates of conversion of some allylic and benzyl chloroformates into the allylic (or benzyl) chloride are reported. Reactions not previously observed for the gas phase are the SNi′ reactions which give the chlorides with allylic rearrangement and the reversible allylic isomerisation of the chloroformates. There are parallel heterogeneous processes which are more extensive at lower temperatures. The ready calculation of rate constants from the data, even when there are several reactions at once, is described and is characteristic of the stirred flow method used.

Catalytic hydrogenation of polychloroalkenes containing a $$CCl_3 - \begin{array}{*{20}c} | \\ C \\ \end{array} = CH_2 $$ or $$CCl_2 = \begin{array}{*{20}c} | \\ C \\ \end{array} CH_2 Cl$$ group

1. We subjected 3,3,3-trichloropropene, 1,1,3-trichloropropene, 3,3,3-trichloropropene, and 1,1,3-trichloro-2-methylpropene to catalytic dimerization by hydrogen in the presence of palladium on barium sulfate. 2. Compounds containing a\(CCl_3 - \begin{array}{*{20}c} | \\ C \\ \end{array} = CH_2 \) group undergo allyl rearrangement to form compounds containing two dichlorovinyl groups\((CCl_2 - \begin{array}{*{20}c} | \\ C \\ \end{array} - CH_2 - )_2 \) under these conditions, their allyl isomers react without rearrangement.

The chemistry of polyenic and polyacetlenic compounds

1. The reactions of sodiomalonic ester with the primary vinylacetylenic bromides formed in the allyl isomerization of tertiary isopropenylacetylenic alcohols have been studied. 2. The reactions of the bromides from 1-bromo-3,4-dimethylpent-4-en-1-yn-3-ol, 2,3-dimethylundec-1-en-4,6-diyne-3-ol, and 2,3-dimethyltridec-1-ene-4,6,8-triyne-3-ol lead to the intramolecular nucleophilic addition of the elements of the malonic ester to the acetylenic bonds with the formation of the corresponding cyclopentene derivatives, the structure of which was confirmed by their IR spectra and some chemical reactions. 3. In the case of the reaction of the bromide from 2,3-dimethylnon-1-en-4-yn-3-ol, no C-C cyclization takes place and, consequently, this intramolecular cyclization depends not only on a cis- configuration of the double bond but also on the electronic nature of the triple bond.

The base-catalyzed isomerization of allyl to propenyl amines

The base-catalyzed isomerization of allyl to propenyl amines

Small-Ring Compounds. XXVII. Nucleophilic Displacement Reactions of Some Halogen-substituted Phenylcyclobutenes1

Displacement reactions between alkali hxlides and several cyclic allylic-type halides, namely, 2,2-dihalo-3-phenylcyclo,-butenones, have been found to proceed with rearrangement to give 2,4-dihalo-3-phenylcyclobutenones. The 2,2-dihalocompounds also were found to rearrange to the corresponding allylic isomers on heating with triethylamine. The allylic iodides, 2-fluoro-4-iodo- and 2-chloro-4-iodo-3-plienyl-2-cyclobutenones,rearranged in reactions with halogens to form 2,2-dihalo-3-phenylcyclobutenones. Evidence is presented for the stereospecific nature of these reactions.