Olefinic Alcohols Research Articles

The photolysis of tetrahydrofuran and of some of its methyl derivatives at 185 nm

The uv photolysis of tetrahydrofuran, 1, 2-methyltetrahydrofuran, 2, cis-2,5-dimethyltetrahydrofuran, 3, trans-2,5-dimethyltetrahydrofuran, 4, and 2,2,5,5-tetramethyltetrahydrofuran, 5, has been investigated by product analysis in the liquid phase, and quantum yields have been determined. The photolysis of tetrahydrofuran itself was also studied in the gas phase at pressures ranging from 1 to 120 atm (pressurizing gas N2); and very little difference was found between the photolytic behaviour of the vapour at 120 atm and that of the liquid. The major products are in ail cases the cyclopropanes and the corresponding carbonyl compounds, as well as the olefinic alcohols and the carbonyl compounds that are isomeric with the starting material. These products are considered to be formed by the two major primary processes [i] and [ii].[Formula: see text]The cyclopropanes formed in reaction [i] retain some excess energy (apparently more than is needed to realize the trimethylene form), and in the photolysis of tetrahydrofuran vapour the hot cyclopropane rearranges to a considerable extent into propene. The propene to cyclopropane yield ratio falls strongly with increasing pressure, to a value of 0.065 at 120 atm. A similar value is observed in the liquid phase photolysis.The five-membered oxyl alkyl diradical from reaction [ii] is the likely intermediate in the cis-trans photoisomerization that is observable with the 2,5-dimethyltetrahydrofurans [Formula: see text]. The photolysis of these compounds also demonstrates that steric factors have a strong bearing on the course of the reaction, e.g. the quantum yield of methylcyclopropane from the cis compound is 0.22, vs. 0.08 from the trans compound.Molecular hydrogen is produced if the tetrahydrofurans carry hydrogen in α-position. Its production is enhanced if the α-position is shared with a methyl group (1 gives a hydrogen quantum yield of 0.07, 2 of 0.17, 3 of 0.27, 4 of 0.29, and 5 of zero).

ChemInform Abstract: NEW METHOD FOR CARBON‐CARBON BOND FORMATION: BIOGENETIC‐TYPE SYNTHESIS OF SAFRANAL

AbstractGeranylacetat (I) reagiert mit der Selenverbindung (II) zu einem Gemisch der Verbindungen (III) und nicht zu den Cyclisierungsprodukten (IV).

Nucleophilic addition to C,C double bonds. III. Chemical reactivity of 1endo, 4endo: 5exo, 8exo‐dimethano‐1,2,3,4,4a,5,8,8a‐octahydronaphthalen‐10syn‐ol and X‐ray structure analysis of its p‐nitrobenzoate

AbstractThe title compound 1 is a further example of an olefinic alcohol that undergoes ether formation under basic conditions (→ 3) although the double bond is not activated by an electron‐attracting group. This unusual reactivity is due to steric compression, which is increased in the 10‐methyl analogue 2. This forms the corresponding ether 7 at a much higher rate. ‐ In a deuteriated medium, base‐catalysed cyclization of 1 gives the exo‐deuteriated ether 6, corresponding to trans‐addition. ‐ An X‐ray structure analysis of 4, the p‐nitrobenzoate of 1, is presented.

Nucleophilic Addition to C, C Double Bonds. Proximity and homoconjugative effects. Preliminary communication

AbstractProximity effects alone as well as in combination with electronic effects are responsible for the observed phenomenon of base‐catalyzed ether formation initiated by nucleophilic attack on a C, C double bond of the tricyclic olefin alcohols 1–10 (Scheme 1, Table 1).With compounds 1–4, bearing a keto group, formation of the ethers 11–14 proceeds through a corresponding homoenolate b (Scheme 2) as an intermediate. In one case such a species could be trapped as the methyl ether 21 (Scheme 3).Special attention is given to the stereochemical course of the homoketonization. Ring opening in 21 under acidic conditions occurs regioselectively, however non‐stereoselectively (Scheme 3). Full regio‐ and stereoselectivity (retention) is observed under basic conditions starting from the unsaturated keto alcohols 1 and 2 (Scheme 4) as well as from the keto ethers 11 and 12 (Scheme 5, Table 2).

New method for carbon–carbon bond formation: biogenetic-type synthesis of safranal

Acid catalysed cyclisation of the olefinic β-hydroxy selenide (5) afforded the cyclic compound (7) which was converted into safranal (16)via the olefinic alcohol (12), diolefinic alcohol (14), and aldehyde (15).

Remote functionalisation by ferrous ion-cupric ion induced decomposition of alkyl hydroperoxides

By decomposition of alkyl hydroperoxides 1-8 with ferrous sulfate-cupric acetate reagent, intramolecular functionalisation of remote non-activated C atom takes place and unsaturated alcohols with double bond mainly at δ-position are obtained. The reaction proceeds involving the corresponding alkoxy radical 9 and δ-carbon radical 10 as intermediates. One-electron oxidative interception of δ-carbon radical by cupric acetate does not involve the corresponding carbonium ion; instead, the alkyl-copper intermediate 11 is formed and by elimination affords olefinic alcohols. The isotope effect for this elimination process was found to be k h /k d =6.1.

Simple syntheses of dihydrojasmone and cis-jasmone via 1,4-diketones

Two new routes for the synthesis of dihydrojasmone (10a) and cis-jasmone (10b)via 1,4-diketones (5a and b) are described. For the first route, pent-4-en-1-ol (1) was oxidised to the corresponding aldehyde (2), which on reaction with suitable Grignard reagents gave the olefinic alcohols (3a and b). The former (3a) was oxidised directly to the diketone (5a) by Jones reagent catalysed by Hg-(OAc)2. The latter (3b) was oxidised stepwise, first by PCC to give (4), then by PdCl2 to yield (5b). For the second route, pent-4-yn-1-ol (6) was converted to the aldehyde (7), which on Grignard reaction using suitable reagents gave the hydroxy-acetylenes (8a and b). These were oxidised to the corresponding acetylenic ketones (9a and b), which in turn were converted by Hg2+ catalysed hydration to (5a and b). Base cyclisation of the diketones (5a and b) yielded (10a and b) respectively.

ChemInform Abstract: TOTAL SYNTHESIS OF YLANGO SESQUITERPENOIDS‐ (+)‐CIS AND (+)‐TRANS‐SATIVENEDIOL, (+)‐HELMINTHOSPORAL, (+)‐HELMINTHOSPOROL, PREHELMINTHOSPORAL, PREHELMINTHOSPORAL DIETHYL ACETAL, (+)‐VICTOXININE, (+)‐ISOSATIVENEDIOL

AbstractAus dem Dien (I) werden (+)‐cis‐ und (+)‐trans‐Sativendiol (IV) bzw. (V) dargestellt.

Total synthesis of ylango sesquiterpenoids: (+)-cis- and (+)-trans-sativenediol, (+)-helminthosporal, (+)-helminthosporol, prehelminthosporal, prehelminthosporal diethyl acetal, (+)-victoxinine, (+)-isosativenediol

Oxidation of the previously prepared olefinic alcohol 26 with chromium trioxide – pyridine in dichloromethane containing trifluoroacetic acid gave the tricyclic ketone 29 as the major product. Hydroxylation of the latter, followed by reduction of the resulting α-hydroxy ketone 31, afforded a 1:1 mixture of (+)-cis- (22) and (+)-trans-sativenediol (23). In view of earlier synthetic transformations reported by a number of different researchers, the present work also constitutes formal total syntheses of the enantiomers of the following sesquiterpenoids: (−)-helminthosporal (1), (−)-helminthosporol (2), prehelminthosporal (3), prehelminthosporal diethyl acetal (4), (−)-victoxinine (8), and (−)-isosativenediol (19).

Stereoselective Total Synthesis of Copa and Ylango Sesquiterpenoids: (−)-Copacamphene, (−)-Cyclocopacamphene, (+)-Sativene, (+)-Cyclosativene

Stereoselective total syntheses of the tricyclic sesquiterpenoids (−)-copacamphene (1) and (+)-sativene (3) and of the related tetracyclic compounds (−)-cyclocopacamphene (2) and (+)-cyclosativene (4) are described. An efficient four-step synthetic sequence was employed to convert the bicyclic dione 5 into the olefinic ketone 8. The latter compound was converted in four steps into the olefinic alcohol 23. Eliminative cyclization of the corresponding tosylate 25 gave (−)-copacamphene (1) in high yield. In similar fashion, (+)-sativene (3) was obtained by cyclization of the olefinic tosylate 42, which in turn was derived via a four-step synthetic sequence from the olefinic ketone 9. Oxidation of the olefinic alcohol 23 afforded the aldehyde 34. Conversion of the latter compound into the p-tosylhydrazone 35, followed by pyrolysis of the corresponding lithium salt 36, gave the pyrazoline 37. Photolysis of 37 afforded, in high yield, (−)-cyclocopacamphene (2). Similarly, (+)-cyclosativene (4) was obtained from the olefinic alcohol 41 via the pyrazoline 46.

Chelation in Cu(I) — Olefinic alcohol complexes

Chelation in Cu(I) — Olefinic alcohol complexes

Copper(I)-promoted substitutions of methoxy and tetrahydro-2-pyranyloxy groups. Synthesis of allenic and olefinic alcohols

Copper(I)-promoted substitutions of methoxy and tetrahydro-2-pyranyloxy groups. Synthesis of allenic and olefinic alcohols

The Formation of Cyclic Ethers by Intramolecular Addition and Substitution Processes in the Reaction of Olefinic Alcohols with Lead Tetraacetate. Part I. Preliminary communication

The Formation of Cyclic Ethers by Intramolecular Addition and Substitution Processes in the Reaction of Olefinic Alcohols with Lead Tetraacetate. Part I. Preliminary communication

High stereo- and regioselectivities in the transition metal catalyzed epoxidations of olefinic alcohols by tert-butyl hydroperoxide

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh stereo- and regioselectivities in the transition metal catalyzed epoxidations of olefinic alcohols by tert-butyl hydroperoxideK. B. Sharpless and R. C. MichaelsonCite this: J. Am. Chem. Soc. 1973, 95, 18, 6136–6137Publication Date (Print):September 1, 1973Publication History Published online1 May 2002Published inissue 1 September 1973https://doi.org/10.1021/ja00799a061RIGHTS & PERMISSIONSArticle Views7862Altmetric-Citations654LEARN 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 (282 KB) Get e-Alerts Get e-Alerts

Total Synthesis of Eremophilane-type Sesquiterpenoids: (±)-Eremophilenolide, (±)-Tetrahydroligularenolide, and (±)-Aristolochene

The total synthesis of the racemic forms of the eremophilane-type sesquiterpenoids eremophilenolide (2), tetrahydroligularenolide (3), and aristolochene (4) is described. The octalone 7 was converted via an efficient, regioselective route into the keto ester 12, which served as a common synthetic intermediate for the preparation of the three sesquiterpenoids. Successive subjection of 12 to alkylation, hydrolysis, and decarboxylation afforded the keto acid 14. Hydrogenation of the latter provided both the cis-fused keto acid 20, which was readily converted into (±)-eremophilenolide (2), and the trans-fused keto acid 15, which was similarly transformed into (±)-tetrahydroligularenolide (3). Conversion of 12 into the dithioketal 23, followed by desulfurization and treatment of the resultant olefinic ester 25 with excess methyllithium, provided the olefinic alcohol 27. Dehydration of the latter yielded (±)-aristolochene (4).

Reactions of some organic peroxides with triphenylphosphine and sodium dialkyl phosphites

AbstractThe reactions of the allylic peroxides ascaridole, cyclohexadiene endoperoxide, and α‐phellandrene peroxide with triphenylphosphine follow an SNi'‐type mechanism. In contrast, the acyclic allylic compounds, allyl tert‐butyl peroxide, α‐cumyl cyclohexenyl peroxide, and tert‐butyl cyclohexenyl peroxide apparently react with triphenylphosphine by a free‐radical mechanism. The saturated cyclic peroxide dihydroascaridole, in which there is no possibility of an allylic rearrangement, gives with triphenylphosphine a mixture of olefinic alcohols. Di‐n‐butyl peroxide is readily cleaved by sodium dialkyl phosphites, but sterically hindered peroxides do not react under similar conditions. Reaction can, however, take place at the oxygen adjacent to a large group if a smaller substituent is present on the other oxygen atom.

Reaction of iodonium nitrate with some olefinic alcohols

Iodonium nitrate in pyridine–chloroform at room temperature undergoes preferential electrophilic addition to certain olefinic alcohols to form (i) hydroxyiodoalkyl nitrates and (ii) hydroxyiodoalkylpyridinium nitrates. Parallel reactions in sym-collidine–chloroform gave three-, four-, and five-membered cyclic ethers as well as products of type (i). Introduction of a hydroxy-function stabilises the intermediate iodonium ion leading to an increase in the product ratio (ii): (i) relative to the additions to alkenes of comparable structure. The trans stereospecific addition of iodonium nitrate to cyclohex-2-en-1-ol indicates that the iodonium ion is formed cis to the hydroxy-group during the reaction.

Electroorganic chemistry IX anodic cyclization of olefinic alcohols to cyclic ethers

Electroorganic chemistry IX anodic cyclization of olefinic alcohols to cyclic ethers

Intramolecular interaction between a hydroxyl group and π-electrons—XXII: Relationship between conformation and frequency shift by intramolecular O—H ⋯ π interaction in olefinic alcohols

In olefinic alcohols the intramolecular interaction between the OH group and the π-electrons is observed as a shift to the lower frequency of the OH stretching band (ν OH, when the molecule is fixed in a conformation in which both groups are mutually in proximity or when it can adopt such a conformation. The closer the interacting groups, the greater the value of the ν OH shift, and Δν OH can be correlated to the degree of the overlap between the orbitals of the OH group and the π-electrons.

Complexation of olefinic alcohols with aqueous silver ion

Complexation of olefinic alcohols with aqueous silver ion