7-methylene-1,4-cyclooctadiene

N4F,2P2RuCl6H24, Ruthenium(II), tetrakis-(acetonitrile)(r)J-, 1,5-cyclooctadiene)-bis[hexafluorophosphate( 1 —)], 26 72 NjFeOGoHjft, Iron, carbonyltetrakis(2-iso-cyano-1,3-dimethylbenzene)-, 26 57 N4Li2Si2C2ftH5ft, Lithium, p.-[(a,cx, l,2-T) a,a, 1, 2-ti- 1,2-phenylenebis[(trimethyl-silyl)methylene]]bis(Af, V,lV, Ar-tetra-methyl-l,2-ethanediamine)di-,... 

Method C. 100 mg (0.4 mmol) of bis[/z-chloro l,2,5,6-> 4-cyclooctadiene (l,5) rhodium], [RhCl(>74-C8H12)]23, is dissolved in 10 mL of methylene chloride and 0.68 g (1.2 mmol) of tppts in 10 mL of water is added. The two-phase system is stirred intensively for 30 min. Then the reaction mixture is transferred to a separation funnel. The aqueous phase is separated and the organic phase extracted twice, in each case with 5 mL of water. The combined aqueous phases are then washed twice with methylene chloride (2x5 mL). The water solution is transferred into a round-bottomed flask and the solvent is removed in a vacuum (10 2 torr). The raw product obtained is sufficiently pure for most reactions. Depending on the stoichiometry, small amounts of tppts or (>74-C8H12)Rh2(/r-Cl)2(tppts)2 are present, which can be removed by column chromatography on Sephadex G-15. Yield 740 mg (93%) red glass-like solid. 

Williams and Reeves138 developed a powerful cascade reaction process for the construction of functionalized cA-bicyclo[3.3.0]octenes. Carbolithiation of 3-methylene-1,4-cyclooctadiene 227 with 1°, 2° or 3° alkyllithium reagents leads to cyclooctadienyl anions,... 

Dichloro(l,5-cyclooctadiene)platinum(II) is a white, air-stable solid. The compound is slightly soluble in solvents such as chloroform, acetic acid, sulfolane (tetrahydrothiophene 1,1-dioxide), and nitromethane. It decomposes slowly upon dissolution in dimethyl sulfoxide. The p.m.r. spectrum of the compound in chloroform shows resonances at 4.38r, /pt H = 65 Hz., for the olefinic protons and 7.29-r for the methylene protons. The infrared spectrum in Nujol has strong absorption maxima at 1334, 1179, 1009, 871, 834, and 782 cm.-1. 

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. 

The complexes (l,5-cyclooctadiene)(2,4-pentanedionato)-palladium(II) and platinum(II) tetrafluoroborate are air-stable solids, soluble in polar organic solvents such as chloroform, methylene chloride, acetonitrile, acetone, or methanol but insoluble in nonpolar solvents such as alkanes, benzene, or ether. Their solutions in acetone have conductivities typical of 1 1 electrolytes. Their proton magnetic resonance spectra (in CDC13 solutions, internal tetramethylsilane reference at 60 MHz.) show peaks due to coordinated cyclooctadiene at 3.78 and 6.7-7.4r (Pd) and at 4.25 and 6.9-7.6r (Pt) and due to the chelated /3-diketone at 4.39 and 7.88r (Pd) and at 4.15 and 7.81r (Pt) with the expected area ratios. In the spectrum of the platinum compound coupling with the 95Pt isotope (33 %... 

These compounds have been obtained by the addition of cyclooctadiene to an equimolar mixture of /i3-allyl or /d -crotyl-(2,4-pentanedionato)palladiuni(II) and tetrafluoroboric acid in methylene chloride-ether solution.1 If silver tetrafluoroborate is on hand, the slight modification described below obviates the need to prepare the /3-diketonate complex as an intermediate. 

The dimer di-Ju-dichloro-bis(/i3-allyl)dipalladium (1.83 g., 5.0 mmoles) and silver tetrafluoroborate (1.95 g., 10.0 mmoles) in methylene chloride (50 ml.) are stirred for 15 minutes. 1,5-Cyclooctadiene (2.0 ml.) is added and stirring continued for a further 2 minutes. The mixture is filtered and the residue washed with methylene chloride (two times with 10 ml.). Ether (150 ml.) is added to the combined filtrate and washings to give a white or greyish precipitate. This is filtered, washed with ether (three times with 50 ml.), and dried in air. The solid is dissolved in methylene chloride (75 ml.), and this solution is... 

It is worth mentioning the synthesis of cyclic a-methylene carbamates, which were also produced via Markovnikov intramolecular nucleophilic addition of O-car-bamates, generated in situ from a propargylic amine and CO2, in the presence of Ru(cod) (cot)/phosphine as catalyst precursor (cod cyclooctadiene cot cycloocta-triene) (Scheme 8.23) [75]. 

Which product will be formed depends on the number of methylene groups between the double bonds. If either one or three CH2 groups are present, the common [2 + 2] cycloaddition is observed with two CH2 groups x[2 + 2] cyclouddition predominates. For cyclic dienes the dependence of the reaction product on the number of CH2 groups is even more pronounced 1,5-cyclooctadiene (56) yields the product 57 exclusively (Sri-nivasan, l%3). 

Three groups independently investigated the addition of this reagent to cyclic dienes. Under proper conditions of dilution, sulfur dichloride adds to noncon-jugated cyclic dienes to give sulfur-bridged systems. Thus Corey and Block stirred a solution of 1,5-cyclooctadiene in methylene chloride at —50° under nitrogen. 

We found that the reaction of bis(cyclooctadiene)nickel(0) with the two ylides ben-zoyhnethylene-triphenylphosphorane and methylene-trimethylphosphorane in toluene yields a highly active homogeneous catalyst (la) without any co-catalyst -the ethylene turnover being approximately tenfold compared to 2 [10]. 

The complex bis(l,5-cyclooctadiene)nickel(0) is obtained as yellow crystals which sublime in vacuo at 90°C and melt with decomposition at 142°C. The infrared (73) and NMR sj)ectra (419) indicate that all double bonds are coordinated to the nickel atom (i.e., Ni is 4 - coordinate) the C=C bands at 1656 and 1490 cm in the free diene are replaced by a strong band at 1328 cm in the complex, while the NMR spectrum shows only two signals (intensity ratio 1 2) at t = 5.64 (olefinic protons) and T = 7.84 (methylene protons). The absence of a center of symmetry (infrared) suggests that configuration (195b) is more probable than (195a), indicating a tetrahedral rather than square planar coordination... 

Figure 4. Catalytic hydrogenation of 1,5-cyclooctadiene in methylene chloride under 500 psi H2 105°C (16)...

Methylenebicyclo[5.1.0]oct-2-ene gives mostly 7-methylene-l,4-cyclooctadiene and smaller amounts of 6-methylenebicyclo[3.3.0]oct-2-ene as well as 8-methylenebicyclo[3.2.1]oct-6-ene in a flow system above 365°C for short reaction times (Scheme 10.63). ... 

Bis(l,5-cyclooctadiene)rhodium tetrafluoroborate (1.4 g, 3.45 mmol) was dissolved in methylene chloride (20 mL), and acetonitrile (5 mL) was added dropwise to the stirred solution. The resultant yellow solution was added to diethyl ether (100 mL) to give bright yellow crystals of 6/5(acetonitrile)(l,5-cyclooctadiene)rhodium tetrafluoroborate (1.15 g, 88%). ... 

A solution of l,2-bis(diphenylphosphino)ethane (dppe) (0.064 g, 0.16 mmol) in methylene chloride (20 mL) was added to a stirred (25 °C) solution of [Rh(CN)2(cod)]Bp4 (0.06 g, 0.158 mmol) in methylene chloride (10 mL). The solution was added to diethyl ether (80 mL) and the precipitate was recrystallized from methylene chloride-hexane to give orange-yellow crystals of l,2-6fr(diphenylphosphino)hane(l,5-cyclooctadiene) rhodium tetrafluoro-borate (0.07 g, 64%). 

Bonnaire and Fougeroux have found [481] that the oxidation of [IrCl(cod)]2, (cod = 1,5-cyclooctadiene) in methylene chloride or benzene gave complexes having the formula [IrCl(OH)(cod) 1/2 L] where L is a molecule of solvent. The IR spectra indicate the presence of an OH group in the products. 

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