Cycloocta-1,5-diene

A mixture of 5.0 g. (8.41 mmoles) of hydrated chloroplatinic acid and 6.2 g. (60 mmoles) of sodium bromide suspended in 15 ml. of glacial acetic acid in a 125-ml. Erlenmeyer flask is heated at 75° for 10 minutes. Six milliliters of 1,5-cycloocta-diene is added to the hot solution yielding a brown solution and a black precipitate containing the impure product. The pure product is isolated in exactly the same manner as that described for the preparation of dichloro(l,5-cyclooctadiene)-platinum(II). The clarified methylene chloride solution is very pale yellow. The yield of the very pale yellow product in the form of a finely divided powder was 3.22 g. (83%). Anal. Calcd. for C8H12PtBr2 C, 20.75 H, 2.61. Found C, 21.21 H, 2.66. 

A 50-ml Schlenck tube equipped with a stirring bar containing bis(l,5-cyclooc-tadiene)-nickel(O) (4.48 mmol), 2,2 -bipyridyl (4.48 mmol), and 1,5-cycloocta-diene (4.48 mmol) was treated with 5 ml of DMF and the ensuing deep blue/ purple solution stirred at 60°C for 30 minutes. The mixture was then treated with 2,7-diiodo-9,9-bis(2-ethylhexyl)fluorene (1.68 mmol) and 2,5-bis(p-bromo-phenyl)-A-(p-hexylphenyl)pyrrole (0.56 mmol) in 20 ml of toluene by syringe and then stirred for 5 days at 75°C. The solution was cooled to ambient temperature and precipitated into a mixture of 100 ml apiece of methanol and acetone and 5 ml concentrated hydrochloric acid. After of the mixture was stirred for 2 hours, it was filtered the solid residue was dissolved in chloroform and re-precipitated in methanol and acetone solution, and re-filtered. The residue was successively washed with methanol, water and methanol, and dried the product was isolated having a Mj, of 47,200 daltons. 

HYDROGENATION CATALYSTS Aretie-chnomium tricarbonyls. (1,5-Cycloocta-diene)(pyridine)(tricyclohexyl-phosphine)iridium(I) hexafluorophosphate. Di-fi.-chlorobis( 1,5-hexadlene)dirhodium. Lindlar catalyst. Palladuim(II) acetate-So-dium hydride-/-Amyl alkoxide. Rhodium catalysts. 

TCNE = Tetracyanoethylene Dipdba = 4,4 -diisopropyl(di-benzylideneacetone) TMM = Trimethylenemethane dppm = (Diphenylphosphino)methane MMLCT = Metal-metal bond to ligand charge-transfer Tp = Hydrido(trispy-razolyl)borate Tp = Hydridotris(3,5-dimethyl-pyrazolyl)bo-rate BAr = (3,5-triflnoromethylphenyl)borate ttab = l,2,4,5-tetrakis(l-iV-7-azaindolyl)benzene tmeda = Tetra-methylethylenediamine bpma = Bis(pyridyhnethyl)amine TFE = Triflnoroethanol dtbpm = Bis(di-terr-butylphosphi-no)methane dmpe = Bis(dimethylphosphino)ethane dcpe = Bis(dicyclohexylphosphino)ethane triphos = Bis(2-diphe-nylphosphinoethyl)phenylphosphine COD = 1,5-cycloocta-diene dppbts = (Diphenylphosphinobutane)tosylate sodium PPE = Poly(jo-phenylene ethylene). 

Bicyclo[6.1.0]non-4-ene is reported to form a 1 1 mixture of both diastereomeric epoxides 118 . This is readily confirmed by force-field calculations which predict a twist-boat conformation as responsible for the. syn-isomer and a chair conformation for the anti-isomer. So much the more puzzling is the complete syn diastereoselectivity182 of the twofold epoxidation of 1,5-cycloocta-diene to give cis-2, where the force field would predict the syn transition state to predominate by only 55 45. 

For y -diketone = l,l,l-trifluoro-2,4-pentanedione, olefin = 1,5-cycloocta-diene or 1,3,5,7-cyclooctatetraene. For yS-diketone = 1,1,1,5,5,5-hexafluoro-... 

The complex has enjoyed relatively little use in organic synthesis. For iridium-catalyzed homogeneous hydrogenation of alkenes, Crabtree s iridium complex ((1,5-Cycloocta-diene)(tricyclohexylphosphine)(pyridine)iridium(I) Hexafluoro-phosphate) is generally preferred, although this readily prepared Ir complex is active. It is more reactive than its rhodium counterpart in the catalytic isomerization of butenyl- to allylsilanes. ... 

Whereas stoichiometric additions of allylpalladium species to norbomene and 1,3-dienes are known (c/. Section 1.2.2.4), simple alkenes (e.g. styrene, cyclohexene, 1,4-cyclohexadiene and 1,5-cycloocta-diene) did not undergo this reaction. However, it can be assumed that the intramolecular ene process (L) — (M) (Scheme 36) is entropically favored and that a subsequent irreversible -elimination (M) —> (N) withdraws the ene product (M) from the equilibrium (L) (M). Further options are insertionfreduc-tive elimination processes (M) (O). The thereby regenerated Pd° species should continue the catalytic... 

Stable olefin-Ni(O) complexes are formed also with 1,5-cycloocta-diene (COD) and cyclooctatetraene (COT), by displacement of cyclo-dodecatriene from (Ci2Hig)Ni (608) or by reduction of nickel acetyl-acetonate (73). The COD complex has also been produced (419) by treating anhydrous NiClg with an excess of iso-C3H7MgBr and COD in ether under UV irradiation. 

Schrauzer and Thyret have described (528, 529, 531) the synthesis of olefin-Ni(O) complexes containing a quinone, in particular, duro-quinone, as a ligand. The red, diamagnetic duroquinone complexes are obtained by reaction of nickel carbonyl with the quinone in excess olefin. They are stable in air and soluble in polar organic solvents and water. Those olefins which form the coiiqilex contain essentially parallel double bonds, e.g., norbornadiene, dicyclopentadiene, 1,5-cycloocta-diene, 1,3,5-cyclooctatriene, or cyclooctatetraene. 

N4F12P2RUC16H24, Ruthenium(II), tetrakis-(acetonitrile) (V-, 1,5-cycloocta-diene)-, bis[hexafIuorophosphate(l -)], 26 72... 

The first catalytic cyclodimerization of 1,3-butadiene (BD) to 1,5-cycloocta-diene using modified Reppe catalysts was reported by Reed in 1954 [4], and only two years later Wilke reported on the titanium-catalyzed synthesis of cyclo-dodecatrienes from BD [5]. It remained for Wilke and his co-workers to show the tremendous versatility and scope of the nickel-catalyzed cyclooligomerizations of... 

The direct dimerization of an alkenyl halide offers a potentially attractive alternative to many of the above two-step procedures. Such a transformation, (12 — 10), can be achieved using bis( 1,5-cycloocta-diene)nickel(O) in the presence of triphenylphosphine. This mild method tolerates the presence of sensitive functional groups such as acrylic esters and has been improved since the original report by the introduction of more convenient catalyst systems such as triphenyl- and trialkyl-phosphine-nickel(O) ... 

Ligand systems containing several functional groups usually react step-wise with metal carbonyls with successive replacement of CO. An example is the photochemical reaction of Fe(CO)s with 1.5-cycloocta-diene 284,287) ... 

Decomposition of the CU2X2 complexes left as residues from such illuminations produced cis,cis-1.5-cyclooctadiene, cis,trans-1.5-cycloocta-diene, and small amounts of trans,trans-1.5-cyclooctadiene (33). (33) gives (32) on illumination 522>. However, is it not yet clear whether free (33) is formed in cyclooctadiene photolysis, and then undergoes rear-... 

These results for 1,3-butadiene, 1,4-pentadiene and 1,5-hexadiene allow the courses of thermal isomerization in other cases to be predicted. Hydroboration of 1,5-cycloocta-diene yields quantitatively a 72 28 mixture of 9-borabicyclo[3.3.1]nonane (9-BBN) (IX) and 9-borabicyclo[4.2.1]nonane (X), both of which exist as dimers. In refluxing THF, the latter can be isomerized to 9-BBN within 1 h. ... 

RhPC32Hn, Rhodium, (1,4-butanediyl)(-q5-pen-tamethylcyclopentadienyl)(tri-phenylphosphine)-, 22 173 Rh2B2N4P4CMIHl2o, Rhodium(I), tetrakis(l-iso-cyanobutane)bis[methylene(di-phenylphosphine)]di-, bis[tetra-phenylborate(l -)], 21 49 Rh20 C,6Hw, Rhodium(l), bis(-q4-1,5-cycloocta-diene)-di-p.-hydroxo-di-, 23 129 IUitO iiHm, Rhodium(l), bis(i)4-l, 5-cydoocta-diene)-di-p.-methoxy-di-, 23 127 RhiOJ K, Rhodium(I), dicarbonylbis-(p-2-methyl-2-propanethiolato)-bis(trimethyl phosphite)di-, 23 124 Rh2Ol2P4S2HM, Rhodium(I), bis(p.-2-methyl-2-propanethiolato)-tetrakis(trimethyl phos-phite)di-, 23 123... 

RuC,6H22, Ruthenium, (t 4- 1,5-cycloocta-diene)(ti6-1,3,5-cyclooctatriene)-, 22 178 RuCi5H2(1, Ruthenium(O), bis(ti2-ethylene)(V-hexamethylbenzene)-, 21 76 RuClgH26, Ruthenium(O), ( nM, 3-cyclohexa-diene)(ri6-hexamethylbenzene)-, 21 77 RuC1P2C4 HJ, Ruthenium(II), chloro(ti5-cyclo-pentadienyl)bis(triphenylphosphine)-, 21 78... 

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