Showing papers on "Double bond published in 1971"
Book•
31 Oct 1971
TL;DR: In this article, the Diels-Alder and related reactions are used for the formation of carbon-carbon double and single carbon double bonds and for the synthesis of organoboranes and organosilanes.
Abstract: Preface to the first edition Preface to the second edition 1. Formation of carbon-carbon single bonds 2.Formation of carbon-carbon double bonds 3. The Diels-Alder and related reactions 4. Reactions at unactivated C-H bonds 5. Synthetic applications of organoboranes and organosilanes 6. Oxidation 7. Reduction References Index.
450 citations
TL;DR: The conjugate addition of cis- or trans-1-alkenyl-cuprolithium complexes (RCHCH)2CuLi · Xn1 to α, β-unsaturated carbonyl compounds was found to occur with high retention of double bond geometry, affording isomerically pure cis or transγ, δ-ethylenic carbonyls compounds.
Abstract: The conjugate addition of cis- or trans-1-alkenyl-cuprolithium complexes (RCHCH)2CuLi · Xn1 to α, β-unsaturated carbonyl compounds was found to occur with high retention of double bond geometry, affording isomerically pure cis- or trans-γ, δ-ethylenic carbonyl compounds. The same 1-alkenylcuprates also react stereospecifically with alkyl halides to give isomerically pure cis- or trans-olefins.
69 citations
TL;DR: In this paper, a highly selective catalyst system was proposed for the hydroformylation of methyl oleate into methyl 9(10)-formylstearate in high yields.
Abstract: A highly selective catalyst system has been discovered for the hydroformylation of methyl oleate into methyl 9(10)-formylstearate in high yields. A rhodium catalyst in the presence of triphenylphosphine is used with oleic esters, acids or triglycerides. Hydroformylation proceeds smoothly at 95-110C with a 1:1 mixture of H2 and CO at 500 to 2000 psi with or without a solvent, such as toluene. The formylstearate obtained in 90% to 99% conversion from oleate can be either hydrogenated (Raney Ni) or reduced (NaBH4) to hydroxymethylstearate or oxidized (KMnO4) to carboxystearate. According to TLC and mass spectrometry, the methylated carboxystearate consists of about equal proportions of the 9 and 10 isomers. Addition of triphenylphosphine inhibits isomerization of the double bond and leads to the formation of a rhodium carbonyl triphenylphosphine complex, which is apparently the active catalyst. Other known methods for hydroformylation (cobalt carbonyl) and carboxylation (Koch’s method) of oleate give a wide distribution of isomers.
65 citations
61 citations
TL;DR: In this article, a series of aromatic amines, their Noxides and the corresponding protonated species are analysed in terms of differential chemical shifts of the N-oxide with respect to the corresponding amine or to the hydrocarbon.
Abstract: The proton NMR. spectra of a series of aromatic amines, their N-oxides and the corresponding protonated species are analysed. The results for different protons are expressed in terms of differential chemical shifts of the N-oxide with respect to the corresponding amine or to the hydrocarbon. These data are compared with calculated shielding values obtained according to the theories of McConnell & Buckingham using published data for the magnetic susceptibilities and electric dipoles of the functional groups. The major part of the shielding by the N-oxide group originates from the electric dipole. If one considers resonance structures for the aromatic N-oxides the single bond structure and the double bond structure for the NO bond are of approximately equal importance.
58 citations
TL;DR: Doering et al. as discussed by the authors studied the potential energy surface for the concerted insertion of singlet methylene into a C-H bond of methane to form ethane and showed that the reaction path resembles qualitatively that suggested previously by Benson.
Abstract: The potential energy surface for the concerted insertion of singlet methylene into a C-H bond of methane to form ethane is studied by the extended Hiickel method. The reaction path is shown in Figures 5 , 6 , and 7. The reaction begins by a n abstraction-like electrophilic attack of a methylene with its empty p orbital impinging in a slightly nonlinear geometry on the H atom. In the intermediate stage of the reaction the H atom is transferred to the methylene while the C-C distance changes little. The reaction terminates in a collapse to the equilibrium ethane structure. The reaction path resembles qualitatively that suggested previously by Benson. There is no indication o n our surface of a competing pathway involving true abstraction. ubiquitous reaction of singlet methylenes is their A rapid and generally indiscriminate insertion into C-H bonds.’ From the time of the discovery of this reaction by Doering and coworkers2 there has existed the question whether the mechanism of the reaction is a direct concerted one (eq 1) or whether a two-step abstraction-recombination path (eq 2) is followed. It :CHZ + R-H + R-CH2-H (1) CH2 + R H + CHs. + R . ( 2 ) CHa. + Re + RCHi appears that both mechanisms are operative but that di(1) See reviews by W. Kirmse, “Carbene Chemistry,” Academic Press, New York, N. Y., 1964; H. M. Frey, Progr. React. Kinet., 2, 131 (1964); J. A. Bell, Progr. Phys. Org. Chem., 2, l(1964). (2) W. von E. Doering, R. G. Buttery, R. G. Laughlin, and N. Chaudhuri, J. Amer. Chem. Soc., 78, 3224 (1956); W. von E. Doering and L. H. Knox, ibid., 83, 1989 (1961). Antecedents for these reactions may be found in the work of H. Meerwein, H. Rathjen, and H. Werner, Chem. Ber., 75, 1610 (1942). rect insertion predominates. Thus Doering and Prinzbach3 found that photolysis of diazomethane in 2methylpropene-l-’4C leads mainly to ‘4C retention at the 1 position in t h e 2-methylbutene product. Retention of configuration results when the insertion occurs at an asymmetric carbon atom. 4 , 5 Predominant one-step (3) W. von E. Doering and H. Prinzbach, Tetrahedron, 6, 24 (1959). (4) (a) W. von E. Doering and L. E. Helgen, private communication; L. E. Helgen, Ph.D. Dissertation, Yale University, 1965; (b) L. Friedman and H. Shechter, J . Amer. Chem. Soc., 83, 3159 (1969); see also A. C. Cope, G. A. Berchtold, P. E. Peterson, and S. M. Sharman, ibid., 82, 6370 (1960); (c) W. Kirmse and M. Buschhoff, Chem. Ber., 102, 1098 (1969); (d) J. A. Landgrebe and R. D. Mathis, J . Amer. Chem. Soc., 88, 3545 (1966); (e) an exception to this conclusion is the reported finding of an insertion occurring with inversion by v. Franzen and R. Edens, Justus Liebigs Ann. Chem., 729, 33 (1969). ( 5 ) J . A . Bell and G. B. Kistiakowsky, J . Amer. Chem. Soc., 84, 3417 (1962). Previous studies of this reaction may be found in C. Rosenblum, ibid., 60, 2819 (1938); M. Vanpee and F. Grard, Bull. SOC. Chim. Belg., 60, 208 (1951); J. Chanmugam and M. Burton, J . Amer. Chem. Soc., 78, 509 (1956). For related studies see H. M. Frey and G. B. Kistiakowsky, ibid., 79, 6373 (1957); H. M. Frey, Proc. Chem. Soc., 318 (1959); C. H. Bamford, J. E. Casson, and A. N. Hughes, Proc. Roy. Soc., Ser. A, 306, 135 (1968); W. Braun, A. M. Bass, and M. Pilling, J . Chem. Phys., 5 2 , 5131 (1970). Journal of the American Chemical Society / 93:23 1 November 17, 1971
57 citations
TL;DR: In this paper, a monometallic mechanism of monomer complexation and addition to the growing chain for the isotactic polymerization of an α-olefin in the presence of α-, γ- or δ-TiCl3 is proposed, which avoids the back-jump of the Ti-R bond required by the COSSEE-ARLMAN mechanism.
Abstract: A monometallic mechanism of monomer complexation and addition to the growing chain for the isotactic polymerization of an α-olefin in the presence of α-, γ- or δ-TiCl3 is proposed, which avoids the back-jump of the Ti-R bond required by the COSSEE-ARLMAN mechanism. The overall activation energy for propagation involved in the latter mechanism should be higher than that allowed by the mechanism proposed here, which may be more easily reconciled with the figure found for polypropylene (∼ 5 kcal/mole). The steric requirement for a Ti atom on the side surface of a crystal to be catalytically active is that monomer complexation must be possible on both the Ti valencies pointing outside: this requires the active site to be slightly protruding above the two neighbouring layers. Each active site is intrinsically chiral; the cis-opening of the double bond is in agreement with the mechanism.
57 citations
TL;DR: In this article, a line-shape analysis of nmr spectra at a series of temperatures was carried out to study the degenerate isomerization of hexafluoroacetone N-phenylimine and its derivatives.
Abstract: The kinetics of the degenerate isomerization about the carbon-nitrogen double bond of hexafluoroacetone N-phenylimine and its p-chloro, p-fluoro, p-methoxy, p-methyl, and p-nitro derivatives have been studied by line-shape analysis of nmr spectra at a series of temperatures. The free energies of activation at 25o were found to be 15.45, 15.53, 15.35, 14.35, 15.14, and 14.90 kcal mol^(-1), respectively. With the exception of the p-nitro compound, the rate constants at 25o give a Hammett plot with a linear correlation coefficient of 0.989 when σ^+ substituent constants are used; the p value is -0.980. The results are interpreted as being the consequence of an inplane inversion about the imine nitrogen of the p-nitro compound and a rotation about the imine carbon-nitrogen bond of the others.
52 citations
TL;DR: The spectra of the endo- and exo-cyclopropano-norbornene were analyzed in this article, and it was shown that a significant homoconjugation exists between the π-orbital of the double bond and the symmetric Walsh-esorbital in the cyclopropane ring in the exoisomer.
Abstract: Photoelectron spectra of endo- and exo-cyclopropano-norbornene ( = endo- and exo-tricyclo[3.2.1.02.4]octa-6-ene) show that a significant homoconjugation exists between the π-orbital of the double bond and the symmetric Walsh-es-orbital of the cyclopropane ring in the exo-isomer, whereas the interaction is negligeable in the endo-derivative.
48 citations
46 citations
TL;DR: In this paper, the site of ring cleavage in the ring-opening polymerization of low strained cycloolefins (induced by tungsten halide based Ziegler-Natta catalysts) has been investigated.
TL;DR: In this article, it was shown that the formation of the complexes containing a metal-metal bond does not necessarily involve the presence of an electron-withdrawing group attached to the vinyl ligand.
TL;DR: In this article, the cationic polymerization of N-vinyl carbazole initiated by tropylium hexachloroantimonate (HX-hexachlorosimonate) and tropyliam perchlorate (Perchlorate) was studied.
TL;DR: The 2,5-Distyryl pyrazine (C20H16N2) as mentioned in this paper has photo-polymerizability in the crystalline state, and it can be obtained by the direct method and refined by the block-diagonal-matrix least squares method using three-dimensional data.
Abstract: 2,5-Distyrylpyrazine(C20H16N2), which has photo-polymerizability in the crystalline state, crystallizes in the orthorhombic system with cell dimensions of a=20.638, b=9.599, and c=7.655 A, including four molecules in the unit cell. The space group is Pbca. The structure has been determined by the direct method and refined by the block-diagonal-matrix least-squares method using three-dimensional data. The molecules is not planar; the average plane of the pyrazine ring makes a dihedral angle of 12.09° with that of the benzene ring. The molecules are spaced by the c-translation forming an almost parallel plane-to-plane stack. In this stack, the ethylenic double bonds approach each other at the shortest intermolecular distances of 3.939 A, since the long axis of the molecule makes an angle of about 30° with the c-axis. Therefore, the polymerization may occur between these double bonds to form a cyclobutane ring.
Patent•
24 Nov 1971
TL;DR: A photo-compensative competition was conducted in this article, where the participants were judged on their ability to cope with good flexibility, hardness, and water resistance, and they were exposed to a LIGHT SOURCE THROUGH an IMAGE-BEARING TRANSPARENCY to EFFECT POLYMERIZATION, and UNpolymerized UNEXPOSED MONOMER is washed away, leaving a RELIEF STRUCTURE SUITABLE FOR PRINTING PLATES.
Abstract: A PHOTOSENSITIVE COMPOSITION COMPRISING (A) ABOUT 100 PARTS BY WEIGHT OF AN UNSATURATED POLYESTER PRODUCED FROM AN ALCOHOLIC COMPONENT COMPRISING AT LEAST ONE POLYOL AND AN ACIDIC COMPONENT COMPRISING AT LEAST ONE UNSATURATED DISCARBOXYLIC ACID, ITS ANHYDRIDE OR ITS METHYL OR ETHYL ESTER AND HAVING AN AVERAGE MOLECULAR WEIGHT OF ABOUT 400 TO 30,000 AND ETHYLENIC DOUBLE BOND EQUIVALENT OF ABOUT 160 TO 3,200, (B) ABOUT 1 TO 50 PARTS BY WEIGHT OF AN ETHYLENICALLY UNSATURATED COMPOUND (I) OF THE FORMULA CH2=C(-R2)-CO-NH-C(-R3)(-R4)-CH(-R5)-CO-R6 WHEREIN R2 REPRESENTS A HYDROGEN ATOM OR MELTHYL GROUP; AND R3, R4, R5 AND R6 REPRESENT A HYDROGEN ATOM, AN ALKYL GROUP OR CYCLOALKYL GROUP HAVING AT MOST 10 CARBON ATOMS, AND ABOUT 10 TO 100 PARTS BY WEIGHT OF A COMPOUND (II) OF THE FORMULA (CH2=C(-R1)-COO)M-X WHEREIN R1 REPRESENTS A HYDROGEN ATOM OR METHYL GROUP; M IS AN INTEGER FROM 2 TO 4; AND X REPRESENTS A RADICAL OF A POLYOL HAVING A MOLECULAR WEIGHT OF AT MOST 1,000 AND M TERMINAL HYDROXY GROUPS FROM WHICH THE TERMINAL HYDROXY GROUPS ARE EXCLUDED, AND, (C) ABOUT 0.0001 TO 10 PARTS BY WEIGHT OF A PHOTOPOLYMERIZATION INITIATOR. THE COMPOSITIONS ARE EXPOSED TO A LIGHT SOURCE THROUGH AN IMAGE-BEARING TRANSPARENCY TO EFFECT POLYMERIZATION, AND UNPOLYMERIZED UNEXPOSED MONOMER IS WASHED AWAY, LEAVING A RELIEF STRUCTURE SUITABLE FOR PRINTING PLATES. THE PLATES ARE CHARACTERIZED BY GOOD FLEXIBILITY, HARDNESS AND WATER RESISTANCE.
TL;DR: In this paper, the double-bond configuration of unsaturated fatty acids is investigated and it is found to be in the eis configuration and the olefinic bonds of polyenoic acids are separated by one methylene group.
Abstract: Publisher Summary This chapter describes the fatty acid metabolism. Fatty acids are present in cells throughout nature and are encountered most commonly in ester linkage to a variety of complex lipids. Fatty acids occur in a spectrum of chain lengths from acetic acid to lignoceric acid and in various isomerie or substituted forms such as saturated, unsaturated, hydroxy, or branched-chain acids. Unsaturated fatty acids are thought to have a particularly important role in the structure and function of cellular lipids. The eis configuration of the double bond appears to be ubiquitous for unsaturated fatty acids. In the polyunsaturated acids, the olefinic bonds are present in a polyallyl configuration separated from one another by a methylene group. The unsaturated fatty acids occurring in nature are characterized by several common structural features. The double bonds are generally found to be in the eis configuration and the olefinic bonds of polyenoic acids are separated by one methylene group. A convenient method of classification of unsaturated fatty acids is by the position of the double bond from the ω -CH 3 carbon of the hydrocarbon chain.
TL;DR: In this article, the sign of the Cotton effect for the lowest energy π → π* transition is discussed for compounds in which the chromophore of interest is a single or conjugated olefinic double bond, with an allylic oxygen substituent.
TL;DR: The data obtained comprehensively characterise the reactivity of the cytosine nucleus towards hydroxylamine and O-methylhydroxyamine and the chemical properties of the products of modification providing a firm basis for the interpretation of the results of functional studies made with polynucleotides and nucleoproteins.
TL;DR: The reaction of the hydrides IrH(CO)2(PPh3)2 with allene and with conjugated dienes to give π-ally complexes M(allyl)(CO)(PPh 3)2 has been studied in this article.
Abstract: The hydrides IrH(CO)2(PPh3)2 and RhH(CO)(PPh3)3 react with allene and with certain conjugated dienes to give π-ally complexes M(allyl)(CO)(PPh3)2. The allyl and 2-methylallyl complexes have also been prepared by reaction of the appropriate Grignard reagent with trans-MCl(CO)(PPh3)2. N.m.r. studies show that the allyl groups are dynamic at normal temperatures. The compound Ir(π-2-methylallyl)(CO)(AsPh3)2 was also prepared by the Grignard reaction.The reactions of these species with carbon, monoxide, hydrogen, and hydrogen chloride have been studied by i.r. and n.m.r. techniques. The solids IrR(CO)2(PPh3)2[R = C3H5(allyl) or C4H7(2-methylallyl)] and Ir(COR)(CO)2(PPh3)2[R = C3H5(allyl), C4H7(2-methylallyl and but-2-enyl), C5H9(1,2-dimethylallyl), or C7H13(1-isopropyl-2-methylallyl)] have been isolated. The IrR(CO)2(PPh3)2 complexes have σ-allyl groups in the solid state but exist in solution largely as dynamic π-allyl systems. The acyl complexes Ir(COR)(CO)2(PPh3)2[R = C4H7(but-2-enyl), C5H9, or C7H13] are formed as mixtures of cis- and trans-isomers about the double bond; CO insertion occurs at the unsubstituted end of the allylic system. There is spectroscopic evidence for the existence of Ir(σ-allyl)(CO)3(PPh3) species in solution.
Patent•
23 Dec 1971
TL;DR: In this article, the double-bonded urethane monomers containing three or more double bonds per molecule and addition polymers and copolymers of these compounds are disclosed.
Abstract: Ethylenically unsaturated urethane monomers containing three or more double bonds per molecule and addition polymers and copolymers of these compounds are disclosed.
TL;DR: The unusual electronic spectrum of the title compound is due to the strong interaction between the π-orbitals of the double bonds and the Walsh orbit of the four-membered ring as mentioned in this paper.
Abstract: The unusual electronic spectrum of the title compound is shown to be due to the strong interaction between the π-orbitals of the double bonds and the Walsh-orbitals of the fourmembered ring.
TL;DR: It was shown by mass spectral data that in all isomers the double bond position was in or near the center of the molecule and, that some of the resolved isomers contained an additional positional isomer.
Abstract: The exact position of the double bond and the probable branch assignments of each hydrocarbon isomer ofSarcina lutea andSarcina flava were determined by derivatives and gas chromatography and combined gas chromatography-mass spectrometry. It was shown by mass spectral data that in all isomers the double bond position was in or near the center of the molecule and, that some of the resolved isomers contained an additional positional isomer. The hydrocarbons were identified as containing methyl branches in the iso or anteiso or both configurations, symmetrically and asymmetrically disposed on the ends of the isomers. The assignment of the methyl branches for each tetrad of four isomers as the isomers emerged from the gas chromatographic column was iso-iso’; anteiso-iso; anteiso-anteiso’; and isonormal for odd carbon-numbered chains, and iso-iso’; anteiso-iso; iso-normal; and anteiso-normal for even carbon-numbered chains. A fifth isomer was identified as a normal-olefin.
Patent•
19 Jan 1971TL;DR: In this article, a process for the production of oxygenated compounds, more specifically aldehydes and alcohols, by reacting an olefin with hydrogen and carbon monoxide in the presence of, as a catalyst, an insoluble polymer containing a functional group, which may be an amine, thiol, phosphine, or arsine group, having chemically bonded to a metal of Group VIII of the Periodic Table.
Abstract: This specification discloses a process for the production of oxygenated compounds, more specifically aldehydes and alcohols, by reacting an olefin with hydrogen and carbon monoxide in the presence of, as a catalyst, an insoluble polymer containing a functional group, which may be an amine, thiol, phosphine, or arsine group, having chemically bonded thereto a metal of Group VIII of the Periodic Table. The metal can be, for example, rhodium, cobalt, or ruthenium. The olefin can contain more than one carbon-to-carbon double bond, may be an open chain or a cyclic olefin, and may be substituted. Further, the olefin may be contained in a refinery stream such as a cracked gasoline. The reaction may be carried out in the presence of a polar solvent.
Patent•
23 Jun 1971TL;DR: In this article, a thermosetting composition is provided which comprises the reaction product of (a) at least one N,N'-bis-imide of an unsaturated dicarboxylic acid, of general formula ##STR1## in which T represents a divalent organic radical containing a carbon-carbon double bond and Q is a DVS of 2 to 30 carbon atoms.
Abstract: A thermosetting composition is provided which comprises the reaction product of (a) at least one N,N'-bis-imide of an unsaturated dicarboxylic acid, of general formula ##STR1## in which T represents a divalent organic radical containing a carbon-carbon double bond and Q is a divalent organic radical of 2 to 30 carbon atoms, (b) at least one polyamine of general formula R (NH.sub.2).sub.x in which x is an integer at least equal to 2, and R represents an organic radical of valency x, the bis-imide being present in an amount of 0.55 to 25 mols per molar --NH 2 group of the polyamine, and (c) at least one monomer other than a bis-imide of formula (I), which contains a carbon-carbon double bond and is heat-polymerizable.
TL;DR: Tetrakis-triphenylphosphine-platinum(0) catalyzes selectively the addition of silane to terminal olefinic double bonds and neither hydrosilylation of internal double bonds nor isomerisations occur with this catalyst as discussed by the authors.
Abstract: Tetrakis-triphenylphosphine-platinum(0) catalyses selectively the addition of silane to terminal olefinic double bonds. Neither hydrosilylation of internal double bonds nor isomerisations occur with this catalyst.
TL;DR: The reaction of Fe3(CO)12 with 2,2,5,5-tetra-methylhex-3-yne gives a complex which appears to contain an iron-iron double bond as mentioned in this paper.
Abstract: The reaction of Fe3(CO)12 with 2,2,5,5-tetra-methylhex-3-yne gives a complex which appears to contain an iron–iron double bond.
Patent•
22 Jan 1971
TL;DR: In this article, a method of preventing double bond migration of a mono-olefin hydrocarbon during the selective hydrogenation of a polyunsaturated hydrocarbon coexisting with a Mono-Olinic hydrocarbon was proposed.
Abstract: A method of preventing double bond migration of a mono-olefin hydrocarbon during the selective hydrogenation of a polyunsaturated hydrocarbon coexisting with a mono-olefinic hydrocarbon, each of the mono-olefinic hydrocarbons and polyunsaturated hydrocarbons having at least four carbon atoms, in the presence of hydrogen, using a palladium- or nickel-hydrogenation catalyst, which comprises adding carbon monoxide to the reaction system in an amount of from 1 to 50 mol. % based on said hydrogen during the initial stage of the selective hydrogenation reaction and following the initial stage, lowering the content of carbon monoxide to a range of from 0.05-1 mol. % based on the hydrogen.
TL;DR: The synthesis of 11,11-dideuterooleic acid was described in this article, where the Wittig reaction was used to introduce the carbon-carbon double bond, giving a mixture of which better than 90% is the desired cis-isomer.
Abstract: The synthesis of 11,11-dideuterooleic acid is described. The Wittig reaction is used to introduce the carbon-carbon double bond, giving a mixture of which better than 90% is the desired cis-isomer. Two alternative routes gave deuterium incorporation of 95 and >98%d2.