Of cyclo-octadiene

The interaction of HO of cyclo-octadiene with unoccupied d orbital of nickel. 

In butadiene di- and dimerization with nickel catalyst and (o-PhCd 1,0)3P as a stabilizing ligand, the yields of cyclo-octadiene and cyclo-dodecatriene... 

Ethenolysis of cycloalkenes is a convenient route for production of certain polyunsaturated compounds. Shell have developed a process for the manufacture of a,w-diolefins via ethenolysis of cyclic olefins (the reverse of Eq. 4) [21,22]. Thus, 1,5-hexadiene and 1,9-decadiene were produced via ethenolysis of cyclo-octadiene and cyclooctene, respectively (Eqs. 7a,b). 

Bridged saturated oxepin derivatives can be produced by oxyselenation of cyclo-octadienes and 5-hydroxycyclo-octenes, e.g. (136), via transannular attack of oxygen on a first-formed episelenium ion the product ratio is solvent-dependent. ... 

Decomposition of (72) in ethanolic sodium hydrosulphite generates, in situ, an azine which fragments to give nitrogen and cyclo-octatetraene. The yield of cyclo-octatetraene is substantially lower than the yield of cyclo-octadiene from (73). The controversy concerning the origin of this result continues. Anastassiou has re-affirmed the view that there is symmetry-controlled opposition to a linear cheletropic process in (72) but not in (73). 

HOaQCHjlfiCOiH, CSH14O4. Important dicarboxylic acid obtained by oxidizing ricino-leic acid (from castor oil) also obtained by oxidation of cyclo-octene or cyclo-octadiene formerly obtained from cork. Used in the formation of alkyd resins and polyamides. Esters are used as plasticizers and heavy duty lubricants and oils. 

An interesting addition reaction of sulfur dichloride has been discovered that allows the preparation in good yield of bridged cyclic sulfides from cyclic dienes. Two examples of the reaction have been described (experimental details of the latter sequence are given below. 

The cycloaddition between norbornadiene (23 in Scheme 1.12) and maleic anhydride was the first example of a /mmo-Diels-Alder reaction [55]. Other venerable examples are reported in Scheme 1.12 [56]. Under thermal conditions, the reaction is generally poorly diastereoselective and occurs in low yield, and therefore several research groups have studied the utility of transition metal catalysts [57]. Tautens and coworkers [57c] investigated the cycloaddition of norbornadiene and some of its monosubstituted derivatives with electron-deficient dienophiles in the presence of nickel-cyclo-octadiene Ni(COD)2 and PPhs. Some results are illustrated in Tables 1.4 and 1.5. 

Among many examples of -orbital interaction, only the following two are selected to illustrate the feature of HO—LU conjugation. One is the cyclooctadiene-transition metal complex ">. The figure indicates the symmetry-favourable mode of interaction in a nickel complex. The electron configuration of nickel is (3d)8 (4s)2. The HO and LU of nickel can be provided from the partly occupied 3d shell from which symmetry-allowed occupied and unoccupied d orbitals for interaction with cyclo-octadiene orbitals are picked up. 

Thus the range of bicyclic peroxides available via peroxymercuration may be quite limited. Nevertheless where the method works best, namely with 1,5- and 1,4-cyclo-octadiene, it makes a valuable contribution in that each peroxymercuration is regiospecific and leads to a dioxabicyclodecane that is isomeric with the [4.2.2] compound 23 available via photooxygenation (Eq. 18). Furthermore, the [3.3.2] compounds derived from 1,5-cyclooctadiene are, to the best of our knowledge, the only bicyclic peroxides obtained to date that do not contain either a 5- or a 6-membered dioxacycloalkane ring. 

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 ... 

Experimental structural data are available for two crystalline derivatives of c/s,cis-cyclo-octadiene-1,5 (86). The distorted-boat form occurs in both crystals (observed C—CH2—CH2—C torsion angles 65 and 74°, respectively). Hedberg and Hedberg have performed a gas-electron diffraction study and found that the distorted boat conformation predominates also in the gas-phase (87). For the dibenzo derivative, however, there are crystallographic indications that in the solid state the eight-membered ring has the chair conformation (88). 

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-... 

By hydrogenation of the diene, the cyclo-octadiene precatalyst can easily be transformed into the solvent complex. 

The relatively easy rearrangement of cis-l,2-divinylcyclobutane was first reported by Vogel (1958) who found that at 120° ci5,cis-l,5-cyclo-octadiene was the only product. 

More recently, kinetic data have become available for the isomerization of this compound and also for the iraws-l,2-divinylcyclobutane (Hammond and DeBoer, 1964). From determinations of the rate of formation of the cia-cis-l,5-cyclo-octadiene from the cis-l,2-divinylcyclobutane at four temperatures between 65 and 108° C, an enthalpy of activation of... 

Another product, which may be the cis-iraws-cyclo-octadiene, is also formed in a small-percentage yield). This is exactly analogous to the transition complex postulated for the isomerization of ci 1,2-divinyl-cyclopropane. 

One case of some interest for which kinetic data are not available, but for which equilibrium data are, is that of cyclo-octa-l,3,5-triene. At 100° there is a rapid equilibration between the triene and bicyclo[4,2,0] octadiene ... 

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,... 

Bicyclo[4,2,0]octene isomerizes smoothly to yield 1,3-cyclo-octadiene only at temperatures appreciably higher than are necessary for the mono-cyclic cyclobutenes. A study of this reaction in the gas phase in the temperature range 235 to 285° C yielded the Arrhenius equation... 

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... 

Hence, two methods are available that can be applied to follow nanoparticles formation and growth (i) an indirect method that utilizes the consumption of molecular hydrogen pressure versus time and (ii) a direct method that follows the loss of precursor by the 1 1 conversion of its cyclo-octadiene ligand to cyclo-octane by GLC measurements. The mechanism developed by Watzky and Finke suggests that the nanoparticles act as Hving-metal polymers -a concept that could be used to obtain particles with defined sizes simply by adding the appropriate amounts of catalyst precursors [32]. 

Scheme 5 Asymmetric MCR synthesis to piperazine intermediate (34) of the Merck HIV protease inhibitor Crixivan (BINAP 2,2 -bis(diphenylphosphino)-1,10-binaphthyl COD cyclo-octadiene)...

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