Related Olefins Research Articles

Nichtplanare Doppelbindung in einem kristallinen Derivat von anti‐Sesquinorbornen (anti‐Tetracyclo[6.2.1.13,6.02,7]dodec‐2(7)‐en)

Non‐Planar Double Bond in a Crystalline Derivative of anti‐Sesquinorbornene (anti‐Tetracyclo[6.2.1.13,6.02,7]dodec‐2(7)‐ene)The olefinic double bond of the title compound 2 has been observed by X‐ray techniques to deviate from planarity by 13.2 (0.3)° (symmetric out‐of‐plane bending). Empirical force field calculations for the parent hydrocarbon 1 (anti‐sesquinorbornene) give a much larger corresponding deviation of 35.6°. The calculated nonplanar double bond deformations in anti‐sesquinorbornene 1 as well as in the syn‐isomer 4 and other related olefins are a consequence of substantial widenings of the exocyclic C(sp3)–C(sp2–Csp3) angles when keeping the double bond planar. The considerable computational exaggeration of this novel out‐of‐plane bending mechanism is attributed to various possible force field deficiencies.

Diastereoselectivity in the rhodium-catalyzed hydroformylation of (+)( R)-1-phenylethyl vinyl ether

The degree of diastereoselectivity in the rhodium-catalyzed hydroformylation of (+)( R)-1-phenylethyl vinyl ether is much higher than that in the hydroformylation of the related olefin, 4-phenyl-1-pentene.

Mutagenic action of structurally related alkene oxides on Schizosaccharomyces pombe: The influence, ‘in vitro’, of mouse-liver metabolizing system

A series of aliphatic epoxides were tested for their ability to induce forward mutations in the yeast Schizosaccharomyces pombe. For all the compounds under study, a linear dose-response relationship was found, and the ranking of the relative specific activity was: epichlorohydrin > ethylene oxide > glycidol > 1,2-epoxybutane > 1,1,1-trichloropropylene oxide > propylene oxide > 2,3-epoxybutane. The influence of the metabolic conversion of the epoxides by the mouse-liver S9 fraction was also investigated. In such conditions, except for the 2,3-epoxybutane, the genetic activity of epoxides seems to be reduced.

Reactions and properties of some trimethyleneplatinum(IV) complexes: XI. Fission of the C 3 moiety in reactions of platinacyclobutanes

The reactions of the platinacyclobutanes [X 2 PtCH 2CHRC H 2(1,10-phenanthroline)] (X  Cl, Br; R  H, CH 3) with unsaturated compounds in methyl cyanide, dimethylformamide and dimethylsulphoxide at room temperature have been investigated. Tetracyanoethylene, and styrene and related olefins, promoted the fission of the C 3 moiety giving ethylene (R  H) and both ethylene and propene (R  CH 3). It is suggested that this gives support to the view that ionization of a halide occurs in these solvents of relatively high dielectric constant and that the five-coordinate positively charged platinacyclobutane species is in equilibrium with a platinum-carbene-olefin complex.

On the stereochemistry of Grignard addition to bicyclo[3.3.1]nonan-2-one. Preferential axial attack on a cyclohexanone system by a bulky nucleophile

Bicyclo[3.3.1]nonan-2-one (1) reacts with methylmagnesium iodide to give, in a high overall yield, a 19:1 mixture of exo-2-methylbicyclo[3.3.1]nonan-2-ol (2) and the endo-epimer (3), respectively. The high propensity of compound (1) for axial attack by a bulky reagent, such as a Grignard reagent, is atypical of bridged cyclohexanones. Possibly, flattening of the bicyclo[3.3.1]nonan-2-one skeleton favours axial attack. Results of the oxymercuriation–demercuriation of related olefins is in accordance with this view.

Nitroxide chemistry. Part XVII [1]. Reaction of bistrifluoromethyl nitroxide with some halogenoalkanes and related alkenes

The mono (bistrifluoromethylamino-oxy)alkanes (CF 3) 2NOCXYZ (X = Y = F, Z = Cl; X = H, Y = F or Cl, Z = CH 3; X = Y = F, Z = CH 3; X = H, Y = Cl or Br, Z = CF 3; X = Cl, Y = Br, Z = CF 3) have been synthesised by treatment of appropriate halogenoalkanes, CHXYZ, with bistrifluoromethyl nitroxide. The 1,2-bis(bistrifluoromethylamino-oxy)alkanes (CF 3) 2NOCH 2CXYON(CF 3) 2 were obtained as by-products in the reactions involving the ethanes CH 3CHXY (X = H, Y = F or Cl; X = Y = F); these products, like their analogues (CF 3) 2NOCHFCF 2ON(CF 3) 2 and (CF 3) 2NOCH 2CCl 2ON(CF 3) 2, were also prepared via attack of bistrifluoromethyl nitroxide on the corresponding ethenes.

Merostabilization in radical ions, triplets, and biradicals. 5. The thermal cis–trans isomerization of para-substituted tetraphenylethylenes

The cis- and trans-isomers of four para-substituted (three disubstituted and one tetrasubstituted) tetraphenylethylenes have been synthesized, separated, and characterized by either dipole moment or X-ray analysis. The rates of thermal isomerization of the disubstituted derivatives in benzene solution correlate with a substituent parameter reflecting substituent effects on benzylic radical stabilities (σ•), which reflects the biradical nature of the transition state for thermal isomerization in this system. A significant rate enhancement is observed for the tetrasubstituted derivative, in which merostabilization of the transition state is possible.The Arrhenius parameters for thermal isomerization in benzene were determined. From the variation observed for the disubstituted derivatives, an estimate of 35.5 kcal mol−1 for the rotational barrier in tetraphenylethylene is obtained. The activation energy for thermal isomerization of the tetrasubstituted derivative is 2 kcal mol−1 lower than those of the other three; this provides an assessment of the importance of merostabilization in this system.The thermal isomerization of some related olefins (e.g. bianthrylidenes and indigo derivatives) is discussed in light of these results.

Participation of the methoxyl group in the cleavage of some 19-substituted steroid epoxides. A case of competition between internal and external nucleophile attack

Acid cleavage of two steroid epoxides III and IV, bearing a methoxy group in position 19, with aqueous perchloric acid or hydrobromic acid gives two types of products, i.e. diols or bromohydrins VI, VII, IX and X as products of the normal reaction course and cyclic ethers V and VIII formed by participation of the 19-methoxy group. Discussed is similarity of these reactions with electrophilic additions to the related 19-methoxy olefins I and II, the mechanism, and the difference in behavior of both epoxides III and IV. Also discussed is the dependence of product ratios on the nucleophility of the attacking species.

Participation of 19-ester groups in the cleavage of 2α,3α- and 5α,6α-steroid epoxides. A case of competition between participation and external nucleophile attack

Acid cleavage of the acetoxy epoxide IIIa with aqueous perchloric acid or hydrobromic acid gave two types of products, i.e. the diol Va or the bromohydrin VIa, and the cyclic ether VIII. The latter compound arises by participation of ether oxygen of the ester group. On reaction with perchloric acid the epoxide IVa gave the diol XIIIa as a product of a normal reaction and the isomeric diol Xa as a product arising by intramolecular participation of the carbonyl oxygen of the 19-acetoxy group. Participation of the 19-ester group is confirmed by the formation of the cyclic carbonate XI when the 19-carbonate IVb is treated analogously. On reaction with hydrobromic acid, the epoxide IVa gave solely the bromohydrin XIVa as a product of the normal reaction course. Discussed is the similarity of these reactions with electrophilic additions to the related 19-acetoxy olefins I and II, the mechanism, the difference in behavior of both epoxides III and IV, the dependence of the product ratio on the nucleophility of the attacking species, and the competition between participation of an ambident neighboring group and an external nucleophile attack.

Additions to bicyclic olefins—X: Stereochemistry of the oxymercuration-demercuration of cis-bicyclo[3.3.0]oct-2-ene, endo-trimethylene-norborn-8-ene and related olefins

The stereochemistry of the oxymercuration-demercurarion (OM-DM) of olefins related to the cis-bicyclo(3.3.0]octane and endo-2,3-trimethylenenorboniane structures was determined. In the case of cis-bicyclo(3.3.0]oct-2-ene, hydration occurs preferentially at the less hindered 3-position, with little preference shown for exo vs endo. The more hindered 2-product shows a 11:1 preference for the exo-product. The presence of Me groups at positions 2- or 3-, results in the formation of the tertiary alcohols with approximately a 4:1 favoring of the exo-isomer. (The oxymercuration intermediate exhibits a rapid equilibration with time. Consequently, the 4:1 ratios may not represent the true limit for the isomer distribution in the initial kinetic product.) Similarly, 2-methylenebicyclo[3.3.0]octane reveals an 8:1 preferential formation of the exo-alcohol. In the case of endo-trimethylene-norborn-8-ene, the oxymercuration stage is extraordinarily slow and the results do not fit this pattern. Possibly the very slow oxymercuration stage permits equilibration of the initial reaction product. On the other hand, the reaction is fast with 8-methylene- endo-trimethylenenorbornane and the product is 100% of the tertiary exo-alcohol. The same behavior is observed for 2-methylenenorbornane. Surprisingly, 2-methylene- endo-trimethy-lenenorbornane fails to undergo oxymercuration. Consequently, both endo-trimethylenenorborn-8-ene and 2-methylene- endo-trimethylenenorbornane exhibit an exceptional inertness toward oxymercuration, presumably related to the highly rigid U-shaped structure of the parent system.

A comparative study of the direct anodic oxidation of olefins and acetylenes in non aqueous solvents

The results of electrode kinetic, preparative and theoretical studies of the direct anodic oxidation of related olefins and acetylenes are compared (phenylacetylene/styrene; vinylacetylene/butadiene; 1,4-diphenylbutadiene/1,4-diphenylbutadiyne). Modified HMO-calculation (β-modification according to bond lengths) predict the observed difference of the half wave potentials of related olefins and acetylenes qualitatively. However the HMO-calculations do not allow the precise prediction of the reactivities of anodically formed radical cations of the acetylenes except for the highly conjugated diphenylbutadiyne. Electrode kinetic and preparative data of the olefin and acetylene oxidation show that both react in the same way ie, are oxidized in the adsorbed state to yield monomeric and dimeric products. The remarkably low dimer yield in the acetylene oxidation is supposed to be due to the decreased adsorbability of the acetylenes at the higher anode potentials which are necessary to oxidize them. This phenomenon is observed, too, if olefins with different half wave potentials are compared.

Additions of dihalocarbenes to steroidal and related model olefins. Carbenic selectivity

Additions of dihalocarbenes to steroidal and related model olefins. Carbenic selectivity

ChemInform Abstract: THE ADDITION OF 2,4‐DINITROBENZENESULFENYL CHLORIDE TO CIS‐ AND TRANS‐1‐ARYLPROPENES AND SOME OTHER OLEFINS

Chemischer InformationsdienstVolume 5, Issue 36 Preparative Organic Chemistry ChemInform Abstract: THE ADDITION OF 2,4-DINITROBENZENESULFENYL CHLORIDE TO CIS- AND TRANS-1-ARYLPROPENES AND SOME OTHER OLEFINS KUNISUKE IZAWA, KUNISUKE IZAWASearch for more papers by this authorTADASHI OKUYAMA, TADASHI OKUYAMASearch for more papers by this authorTAKAYUKI FUENO, TAKAYUKI FUENOSearch for more papers by this author KUNISUKE IZAWA, KUNISUKE IZAWASearch for more papers by this authorTADASHI OKUYAMA, TADASHI OKUYAMASearch for more papers by this authorTAKAYUKI FUENO, TAKAYUKI FUENOSearch for more papers by this author First published: September 10, 1974 https://doi.org/10.1002/chin.197436084Read 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. Volume5, Issue36September 10, 1974 RelatedInformation

The Addition of 2,4-Dinitrobenzenesulfenyl Chloride to cis- and trans-1-Arylpropenes and Some Other Olefins

Abstract Kinetic investigations were carried out on the addition of 2,4-dinitrobenzenesulfenyl chloride to the geometrically isomeric pairs of various 1-arylpropenes as well as some related olefins. All the trans isomers of 1-arylpropenes were more reactive than the corresponding cis isomers and the Hammett correlations were observed for respective isomers with ρ=−2.64 (trans) and −2.3 (cis). By contrast, cis-alkenes were more than 10 times as reactive as the corresponding trans isomers. The reactivities of various unsaturated compounds in this reaction were found to be correlated with their ionization potentials constituting two lines accodring to the type of substrates. It was concluded that the greater reactivity of trans-1-arylpropene as compared with the cis isomer is ascribable to the difference in the charge-transfer interaction between the electrophile and a substrate at the transition state. The conclusion is contrasting to the generalization that the relative cis/trans reactivity of alkenes is determined mainly by the Coulombic interaction at the transition state.

Use of benzyne promoters in the conversion of benzenediazonium acetate into benzyne

The observations that 1,1-diphenylethylene and a series of related alkenes act as promoters for the formation of benzyne from benzenediazonium acetate even in the presence of furan, which otherwise promotes the competing radical reaction, leads also to an explanation of the hitherto puzzling promoting effect of tetraphenylcyclopentadienone.

Solvomercuration-demercuration. V. Additions to bicyclic olefins. VI. Stereochemistry of the oxymercuration-demercuration of norbornene, 7,7-dimethylnorbornene, and related olefins

Solvomercuration-demercuration. V. Additions to bicyclic olefins. VI. Stereochemistry of the oxymercuration-demercuration of norbornene, 7,7-dimethylnorbornene, and related olefins

The structure of the nickel bis(1,2-ethenedithiolate)/2,3-dimethylbutadiene cycloaddition reaction product

Summary The synthesis and chemistry of the cycloaddition products formed by reaction of various dienes with nickel bis(1,2-ethenedithiolate) is reported An orbital correlation model previously proposed in describing these and the related olefin reactions is supported by an X-ray diffraction study of the 2,3-dimethylbutadiene/nickel bis(1,2-ethenedithiolate) structure. This study confirms that the products formed by olefins and dienes are close structural relatives. Briefly the structures show a tetradentate sulfur ligand coordinated to square planar nickel. The central ring of the three chelate ring structure is formed in the cycloaddition reaction, and in the present case of a seven membered ring is completely strain free. Bond lengths and molecular properties suggest that reaction is redox in nature with nickel bis(1,2-ethenedithiolate) being the oxidant or acceptor molecule. The crystals studied were monoclinic P 2 1 / c with a =7.393(9), b =13.624(21), c = 20.003(26)A and β=90.80(5)°. The unit cell contains 4 formula units and the structure was solved using 1333 diffractometer measured intensities and refined to a final R factor of 0.094 based on F .

Acid-catalyzed alkylation and cyclialkylation of the cymenes with isobutylene and related olefins

Acid-catalyzed alkylation and cyclialkylation of the cymenes with isobutylene and related olefins

Quantitative studies in carbene chemistry. Part I. Rate-constant ratios for addition of dichlorocarbene to α-methylstyrenes and related olefins

A competitive method has been used to measure the relative reactivities at 0° of a series of α-methylstyrenes (ArCMeCH2) and related olefins towards dichlorocarbene generated by the reaction of potassium t-butoxide with chloroform. Estimation of the unchanged olefins and the products, dichlorocyclopropanes, demonstrated the absence of side reactions. The results confirm the electrophilic character and singlet nature of the carbene. Data for the 3- and 4-substituted compounds correlate well (r= 0·99) with the Hammett–Brown σ+ constants yielding a ρ-value of –0·378 ± 0·015. It is suggested that in the transition state the olefinic π-electrons are asymmetrically partially delocalised into the vacant p-orbital of dichlorocarbene. The results for the 2-substituted α-methylstyrenes and other olefins demonstrate the importance of steric and conformational factors. The preparation of the dichlorocyclopropanes and a new modification of the Wittig reaction are described.

Olefin isomerisation. Part I. Equilibration of octalins related to steroid olefins

By use of a basic catalyst, lithium β-aminoethylamide in ethylenediamine–benzene, trans-Δ1- and trans-Δ2-octalins have been equilibrated at three temperatures, and free energies, enthalpies, and entropies of isomerisation have been deduced. Similar but less precise information has been obtained for the interconversion of the corresponding cis-Δ1- and -Δ2-octalins. The thermodynamic data are compared with those resulting from other experimental work on related steroid olefins and with the theoretical predictions of quantitative conformational analysis. For the process trans-Δ1- octalin →trans-Δ2-octalin, as dilute solutions in ethylenediamine–benzene (2 : 1), our best values are ΔH=–0·52 ± 0·06 kcal./mole, ΔS=–0·8 ± 0·3 cal./(deg. mole); for the cis-isomers corresponding estimates are +0·25 ± 0·25 kcal./mole and –0·8 ± 0·7 cal./(deg. mole), respectively.