Cyclo-octa-l,5-diene

OJFuR CmHm, Ruthenium(II), p-aqua-bis-(p-trifluoroacetato)bis[(T)J-cyclo-octa-l,5-diene)(trifluoroacetato)-, 26 254... 

Direkte UV-Bestrahlung wandelt Cycloocta-l,3,5-trien (Formel 121) hauptsachlich in Bicyclo[4,2,0]octa-2,7-dien (Formel 122) und Tricyclo-[3,2,l,0a-8]oct-3-en (Formel 123) (58,222,340) um. Daneben werden noch all-trans-Octatetra-l,3,5,7-en (222) und Cyclo-octa-l,5-dien (58) nach-gewiesen. 

M. Green, A. Laguna, J. L. Spencer, and F. G. A. Stone, Bis(r -cyclo-octa-l,5-diene)-platinum and -palladium with Fluoroolefins, J. Chem. Soc., Dalton Trans. 1977, 1010-1016. 

R. Mackenzie, and P. L. Timms, Reaction of Metal Atoms with Solutions Preparation of Bis(cyclo-octa-l,5-diene)iron(0), J. Chem. Soc., Chem. Comm. 1974, 650-651. 

Olefinic complexes of copper have been reviewed in Volume 12 of this series (289). Since the appearance of this review, [Cu(cycloocta-l,6-diene)2]BF4 has been prepared by electrolysis of Cu(BP4)2 in methanolic diolefin at copper electrodes (231). Complexes (cycloocta-l,5-diene)Cu02C-CPg, (cyclooctatetrene)(Cu02C CPa)2, and (cyclo-octa-l,5-diene)(Cu02C CF3)a have been obtained as white or pale yellow solids by reacting CuOaC -CFg with the olefins in pentane or benzene, respectively (107). The structure of Cu2Gl2(trans-cyclooctene)3 (Fig. 10) has been determined (124) and is reminiscent of the structure of Cu2Cl2(PPh3)3 (Fig. 5). 

Cyclo-octa-l,5-diene reacts with diphenylacetylene to give a high yield of intramolecular reaction product of this 1 2 alkyne alkene type (equation 46) . ... 

Under an argon atmosphere methylenecyclopropane (8.0 g, 148 mmol) was added to (2,2 -bipyridine)(cyclo-octa-l,5-diene)nickel (2.98 g, 8.50 mmol) cooled to — 78°C. The violet suspension was warmed to — 30"C and stirred for 2 h at this temperature. A black precipitate was formed and the solution turned colorless. After filtration at — 78 °C, the filter residue was washed with EtjO (2 mL portions) until the color of the solution formed turned from violet to green. The remaining solid, after drying in vacuo (25°C/0.5 Torr), gave dark-green microcrystals yield 2.26 g (94%) dec. 140 °C. 

Anchored complexes on silica of the type —(PPh2) IrCl have been prepared and their ability to catalyse the hydrogenation of olefins and dienes was studied. The ability of anchored complexes to isomerize and hydrogenate cyclo-octa-l,5-diene has been investigated. The immobility of the bound PPh2 groups helps to keep the intermediate unsaturated. 

The rates of epoxidation of cyclododecene with a series of aliphatic peroxy-acids have been correlated, using the Taft equation. The reaction constant (p ) was + 2.0 and the steric constant (6) was found to be essentially zero. A two-parameter correlation has been found for the effect of basicity and polarity of the solvent on the rate of epoxidation of propene with peracetic acid. Rate constants and activation parameters for the epoxidation of a number of cycloalkenes, including (11 R = H or COOMe), (12 R = H, Ph, or 2-furyl), (13), (14), and cyclo-octa-l,5-diene, have been measured. An isokinetic relationship was demonstrated, with the isokinetic temperature of 3 C. There was only a weak dependence of the rate on the structure of the alkene. 

When the valence tautomer of cyclo-octa-l,5-diene (stable below —20 C) is treated with O2 under irradiation from a sodium vapour lamp (a street lamp), in the presence of tetraphenylporphyrin as sensitizer, the endo-peroxide (105) can be prepared in 85% yield. The endoperoxide serves as the starting material for three triepoxides (106), (107), and (108) (Scheme ). The structures of all three triepoxides have been confirmed by X-ray analysis. 

Two diaUcyl boranes arc in common use. The bicyclic 9-borabicyclo[3.3.1 ]nonane (9-BBN), introduced in Chapter 34 as a reagent for diastereoselective aldol reactions, is a stable crystaUine solid. This is very unusual for an alkyl borane and makes it a popular reagent. It is made by hydroboration of cyclo-octa-l,5-diene. The second hydroboration is fast because it is intramolecular but the third would be very slow. The regioselectivity of the second hydroboration is under thermodynamic control. 

A system for condensation of metal atoms into a cooled solution has been developed [390]. Condensation of iron vapour into a solution of cyclo-octa-1,5-diene in methylcyclohexane at —120°C yielded bis(cyclo-octa-l,5-diene)iron. 

Singlet oxygenation of cw,c -cyclo-octa-l,5-diene produces 6-hydroperoxy-cyclo-octa-1,4-diene and on further oxidation 5,8-dihydroperoxycyclo-octa-1,3-diene. Since reduction of this hydroperoxide with PhaP leads to cw-5,8-dihydroxy-cyclo-octa-1,3-diene, the whole sequence represents a convenient synthetic entry into 5,8-difunctionalized oxygen derivatives of cyclo-octa-1,3-diene. A highly stereoselective method has been developed for the cw-oxygenation of cycloheptyl systems. This involves irradiation of methanolic solutions of 1-acetoxy-cyclohepta-3,5-diene in the presence of haematoporphyrin as sensitizer to give... 

Reagents i, Bis(cyclo-octa-l,5-diene)nickel(0), PPh3... 

CaFa-PhMe system obeys Raoult s law despite the significant heat of mixing. Solid-liquid phase equilibrium diagrams have been determined for the CaFa-cyclohexa-1,3-diene (exploratory measurements only) and CeFa-cyclo-octa-l,5-diene systems, both of which form addition compounds, and for CaFa-cyclohexane (no compound formation) in this case the tesults are discussed in terms of charge-transfer complexes. ... 

Triphenylmethyl tetrafluoroborate (2.98 g, 9.1 mmol) in dichloromethane (40 mL) was added dropwise to a solution of acetylacetonato(l,5-cyclooctadiene)rhodium (2.8 g, 9.1 mmol) and 1,5-cyclooctadiene (5 mL excess) in dichloromethane (20 mL) at 25 °C. The yellow solution turned deep red, and was then stirred for 5 min. The solution was added to diethyl ether (400 mL) and the resulting orange-red crystals of bis(cyclo-octa-l,5-diene)rhodium tetrafluoroborate (3.44 g, 94%) were collected. ... 

Dimethylvinylidene carbene generated from 3-chloro-3-methylbut-l-yne using aqueous KOH and a phase-transfer catalyst, has been added to cis,cis-cyclo-octa-l,5-diene to give the mono-adduct. ... 

Treatment of cis,cis-cyclo-octa-l,5-diene with palladium chloride or palladium acetate in acetic acid gave the diacetoxybicyclo[3,3,0]octane (220). 5-Methylbi-cyclo-[3,3,l]nonan-l-ol(221 X = OH), l-chloro-5-methylbicyclo[3,3,l]nonane(221 X = Cl), and l-bromo-5-bromomethylbicyclo[3,3,l]nonane, were obtained when 1,5-dimethylenecyclo-octane was treated with sulphuric acid, hydrogen chloride, and bromine, respectively. ... 

Treatment of 5,8-bis(trimethylsilyl)cyclo-octa-l,3,6-triene or 3,5,8-tris(trimethyl-silyl)cyclo-octa-l,3,6-triene with triruthenium dodecacarbonyl gave the pentalene complexes (352 X = H or SiMe ). Tricarbonyl(Ti-cyclo-octa-l,5-diene)ruthenium and tricarbonyl(T)-cyclo-octa-l,3-diene)osmium have been prepared. They react with trityl fluoroborate to give cyclo-octadienylium complexes [(CgHn)M(CO)3] which react with anionic nucleophiles to give neutral compounds, some of which... 

Dimethylcyclo-octa-1,5-diene reacts with boron trifluoride diethyl etherate to give 2,5-dimethylbicyclo[3,3,0]oct-2-ene (60%), whereas l,5-dimethylbicyclo[3,2,l] octan-8-ol (156 R = H 50%) and its tosylate (156 R = Ts 70%) are formed on treatment with perchloric acid-aqueous dioxan and toluene-p-sulphonic acid, respectively. Preliminary results indicate that cis,ci -cyclo-octa-l,5-diene and hydrogen peroxide-mercury(ii) nitrate react to give a transannular peroxide. The boron trifluoride diethyl etherate-benzene catalysed cyclizations of the cyclo-octenyl ester (157 R = COjEt) and ketone (157 R = COMe) to the bicyclo[3,3,l]nonanes (158 R = C02Et) and (158 R = COMe), respectively, have been studied further. Possible intermediates in these reactions were synthesized but no cyclized products were obtained. The mechanism that was finally suggested involves protonation of the... 

When di-p-chloro- and di-p-methoxidobis(2-methoxycyclo-oct-5-enyI)dipallad-ium(ii) were refluxed in methanol with and without added base, and when dichloro-(cyclo-octa-l,5-diene)palladium(ii) was refluxed in methanol with added base, complex mixtures of products were obtained comprising cyclo-oct-4-enyl methyl ether, cyclo-oct-4-enone, and cyclo-octa-2,4-, -2,5-, -3,5-, and -1,5-dienyl methyl ethers. 

The ease of isomerization and the product distribution are greatly influenced by the catalyst employed, (290) becoming the major product by use of the catalyst system derived from bis(cyclo-octa-l,5-diene)nickel(0) and tetracyanoethylene. The origins of the peri- and regio-selectivities have been explained in terms of a MO treatment extended-Huckel calculations reveal that among the strained C—C bonds the C-2—C-5 and structurally equivalent bonds have MO shapes suitable for edge-on... 

The 1 1 complex derived from phenyltungsten trichloride and aluminium trichloride is an effective catalyst for diene-cyclobutane metathetical interconversions. Thus, the tetracyclic compounds (291) and (292) were respectively isomerized to the dienes (293) and (294). Rather more surprising was the virtually quantitative formation of the cyclobutanoid compound (296) from (295). Reaction of norbomadiene with 2,2 -bipyridyl(cyclo-octa-l,5-diene)nickel at 25°C yielded the exo-trans,endo-metal o-carbocyclic (297) which, on treatment with an activated olefin (e.g. maleic anhydride), afforded the cyclo-dimer (298 predominantly exo-trans,endo) in good yield by displacement of the hydrocarbon moiety. Catalytic conversions can also be achieved. 

The complex bis(cyclo-octa-l, 5-diene)iridiumtrichlorotin, of previously uncertain constitution, is found to contain the SnCl group linked through tin to the iridium atom. The distance Ir-Sn, 2,73 A (at a stage of refinement R s 12,9%), is fairly close to a value derived from normal radii applicable to compounds not containing metal-metal bonds. 

Hexafluorobut-2-yne adds to the 1,4-positions of the rhodiunv-acetyl-acetonate ring of acetylacetonato(cyclo-octa-l,5-diene)rhodium, and this adduct reacts with hexakis(trifluoromethyl)benzene, formed in situ, to give complex (86a), in which the cyclo-octadiene has been displaced. This structure is confirmed by single-crystal A -ray diffraction. The same product is formed from the corresponding (hexachloronorbomadiene)rhodium complex, but with acetylacetonatobis(ethylene)rhodium or the (ethylene)-(tetrafluoToethylene)rhodium complex, the cyclohexadiene complex (87), in which the one molecule of ethylene is incorporated into the co-ordinated... 

Bis(trifluoromethyl)platinum complexes may conveniently be prepared by the reaction of dimethyl(cyclo-octa-l,5-diene)platinum with trifluoro-iodomethane in methylene chloride, followed by displacement of the cydo-octadiene with the required ligand L (L = AsMcs, PMeaPh, pyridine, RNC, etc.) Oxidative addition of iodine thence gives the platinum(iv) compounds ... 

Hexaduoroazomethane reacts at -70°C with bis(cyclo-octa-l,5-diene)-nickel to give a low yield of an unstable solid which is formulated, on the basis of micro-analysis and mass spectrometric results, as the three-mem-bered ring complex (130), analogous to known unfluorinated compounds. " Phosphine-substituted zerovalent-nickel and -platinum complexes fail to give analogous complexes with hexafluoroazomethane under the conditions investigated. 

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