Cyclo-octadiene

The cis-, 2-divinylcyclobutane in the reaction mixture rearranges rapidly under reflux to the higher-boiling 1,5-cyclo-octadiene. 

Another recent application to the activation of transition metals was reported (247) by Bonnemann, Bogdavovic, and co-workers, in which an extremely reactive Mg species was used to reduce metal salts in the presence of cyclopentadiene, 1,5-cyclo-octadiene, and other ligands to form their metal complexes. The reactive Mg species, characterized as Mg(THF)3 (anthracene), was produced from Mg powder in THF solutions containing a catalytic amount of anthracene by use of an ultrasonic cleaning bath. A plausible scheme for this reaction has been suggested ... 

Similar low activities were found in the hydrogenation of 1-octene [47]. The use of [Ni(PPh3)2I2] in the hydrogenation of norbomadiene resulted in considerable amounts of nortricyclene, via transannular ring closure, whereas 1,5-cyclo-octadiene yielded bis-cyclo-[3.3.0]oct-2-ene. According to these authors, the re-... 

XII. Tricyclic Systems Containing a Cyclobxttane Ring The only system of this kind which appears to have been investigated kinetically in detail is tricyclo[3,3,0,0 ]octane (Srinivasan and Levi, 1964). At temperatures in the range 327 to 366° C the isomerization is a homogeneous first-order reaction. The observed products were 4-vinyl-cyclohexene, butadiene and 1,5-cyclo-octadiene. However, from separate studies on the cyclo-octadiene, it is concluded that the tricyclo-octane first isomerizes to the cyclo-octadiene which then undergoes secondary reactions to yield the other observed products. The observed rate is then the rate of this primaiy reaction, viz. ... 

The remarkable tricyolo-octanes shown below have recently been synthesized (Avram et al., 1964). They both yield 1,5-cyclo-octadiene on pyrolysis at 150° C which suggests that the Mnetic parameters for these isomerizations cannot be two dissimilar to those for the isomerization of bicyclo[2,2,0]hexane,... 

Dihydromesitylene likewise gives a 1,3 complex (34) and 1,4-cyclohexadiene gives 1,3-cyclohexadieneiron tricarbonyl. 1,5-Cyclo-octadiene on treatment with catalytic quantities of Fe(CO)g gives 1,3-cyclooctadiene (35), as the iron tricarbonyl complex is probably not very stable and is continuously displaced by fresh 1,5-diene until isomerization is complete. 

In contrast, 1,5-cyclo-octadiene remains coordinated during the catalytic cycle of hydrogenation of phenylacetylene to styrene, catalyzed by the related iridium complex [Ir(C0D)( Pr2PCH2CH20Me)]BF4. This complex, which contains an ether-phosphine-chelated ligand, catalyzes the selective hydrogenation reaction via a dihydrido-cyclo-octadiene intermediate. The reaction is first order in each of catalyst, phenylacetylene and hydrogen [11] the proposed catalytic cycle is shown in Scheme 2.3. 

It is Hkely that the diene also remains coordinated during the hydrosilylation reactions of phenylacetylene with HSiEts, catalyzed by [Ir(diene)(NCMe)(PR3)]BF4 complexes [PR3 = P Pr3, PMe3 diene = 1,5-cyclo-octadiene, tetraflorobenzobarre-lene (TFB)]. However, detailed studies on the [Ir(COD)(NCMe)(PMe3)]BF4 complex show that cyclo-octadiene carmot be considered, in this case, as an ideal innocent Hgand because it transform into complexes containing cyclo-octadiene, cyclo-octadienyl or cyclo-octenyl Hgands in a variety of coordination modes, due to an... 

Soluble and stable iridium nanoparticles (3.0 0.4nm diameter) have been prepared by reduction of the polyoxoanion-supported lr(l) complex (n-Bu4N)sNa3 [(C0D)lr(P2WisNb3062)] (COD = 1,5-cyclo-octadiene) with molecular hydrogen in... 

BrF NjPRuC H, Ruthenium(II), tris-(acetonitrile)bromo(V-1,5-cyclo-octadiene)-... 

FEAST (further exploitation of advanced shell technology), another Shell process142-144 commercialized in 1986, utilizes a highly active promoted rhenium-on-alumina catalyst (100°C, 2 atm) to synthesize 1,5-hexadiene from 1,5-cyclo-octadiene [Eq. (12.30)] and 1,9-decadiene from cyclooctene [Eq. (12.31)] ... 

Abbreviations arene, i/6-benzene or substituted benzene derivative bipy, 2,2 -bipyridyl Bu, Bu", Bu, iso-, n-, or rerf-butyl COD, 1,5-cyclo-octadiene Cp, /5-C5H5 DAD, dimethyl-acetylene dicarboxylate dam, 1,2-bis(diphenylarsino)methane DBA, dibenzylideneacetone DMF, A. A -dimethylformamide dpe, l,2-bis(diphenylphosphino)ethane dpen, os-l,2-bis(di-phenylphosphino)ethylene dpm, 1,2-bis(diphenylphosphino)methane ESR, electron spin resonance F6-acac, hexafluoroacetylacetone FN, fumaronitrile MA, maleic anhydride Me, methyl MLCT, metal ligand charge transfer phen, 1,10-phenanthroline Pr , Pr", iso- or n-propyl py, pyridine RT, room temperature TCNE, tetracyanoethylene tetraphos, (Ph2PCH2CH2)jP THF, tctrahydrofuran Xylyl, 2,6-Me2C6H3. 

The co-product of the addition of water to the 7r-oxo-allyl rhodium complex, 5, in THF at 25°C was suggested to be an (unobserved) hydroxy rhodium species which rapidly dimerises to give complex 7, a square planar /z-hydroxy dimer. This complex was easily identified by the high field shifts of the /z-hydroxy protons ( — 1.9 ppm) and its symmetry (a single Rh-coupled doublet is observed at 55 ppm in the 31P 1H NMR spectrum). The assignment was confirmed by independent synthesis [(S)-BINAP)Rh(/x-Cl)]2 reacted cleanly with KOH in aqueous THF to give 7, as did addition of (S) -BINAP to the conveniently prepared complex [Rh(/z-OH)(cod]2 (cod = 1,5-cyclo-octadiene). 

Synthesis of (Pentamethylcyclopentadienyl)bromo(1,5,-cyclo-octadiene)osmium(ll), (C5Me5)Os(COD)Br [75g]... 

To a slurry of (CsMes C Ihq (0.62 g, 0.64 mmol) in ethanol (40 mL) was added 1,5-cyclo-octadiene (0.82 mL, 6.7 mmol). The solution was refluxed for 90 min, and the solution color changed to a clear orange and an off-white precipitate formed. The solvent was removed under vacuum, the residue was extracted with diethyl ether (4-30 mL), and the extracts were filtered. The filtrates were combined, concentrated to ca. 50 mL, and cooled to —20°C to afford orange crystals. Additional crops of crystals were obtained by further concentrating and cooling the supernatant. Yield 0.48 g (74%). 

The ruthenium 7i-complex 833 was isolated after US irradiation of the reaction system containing ruthenium trichloride, zinc powder, methanol, and 1,5-cyclo-octadiene (3.288) [747] ... 

An EPDM rubber is produced by the terpolymerisation of ethylene and propylene with a small amount (typically of the order of 5%) of an unconjugated di-olefin. The di-olefins used, include dicyclopentadiene, 1,4-hexadiene, 5-methylene-2-norbornene, 5-ethylidene-2-norbornene and methyl tetrahydroindene, 1,5 cyclo octadiene. A number of other dienes [74,75] have been tried. Infrared spectroscopy [35] is used to find out the ter monomer content. The characteristic peaks for the ter monomer are shown in Table 3.4. In view of the relatively low concentrations, it is probable that ter monomer base units are present largely as isolated units in EPDM but the distribution of propylene and methylene sequences is of considerable interest. 

Natural products containing six-membered rings are ubiquitous, therefore the following set of target molecules are limited to those containing eight-membered rings that would be accessible via [4+4] cycloadditions. Notably, 1,5-cyclo-octadienes 88 can be converted to bicyclo[3.3.0]octanes 201 transannular electrophilic [124] and radical cyclization (Sch. 44) [125]. 

The hydrogenation of 1,5-cyclo-octadien (COD) to cyclo-octene (COE) is performed in a slurry reactor. The reaction is relevant because the product is an intermediate for the production of special polymers. However, this reaction suffers from the drawback that the hydrogenation does not stop at cyclo-octene, because a full hydrogenation to cyclo-octane (COA) is possible, as shown in Figure 4.1.12. 

Figure 4.1.12 Reaction scheme of the hydrogenation of 1,5-cyclo-octadien.

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