Cyclohexane 1.5- Cyclooctadiene

This catalyst (1) is a selective catalyst for hydrogenation of 4-octyne to cw-4-octene (90% yield). If the product is left in contact with 1, it isomerizes to the trans-isomer. Since monoalkenes are hydrogenated slowly with this catalyst, cyclo-octene can be obtained from either 1,3- or 1,5-cyclooctadiene. Of more interest, benzene can be hydrogenated to cyclohexane (83% yield). One drawback is that the catalyst loses about 90% of its activity after one cycle. 

The (l,5-cyclooctadiene)silver(l) nitrate solution is stirred vigorously and the sodium hexafluoroacetylacetonate solution is added, yielding a flocculent white precipitate. The white product is collected on a sintered-glass filter, washed with two 40-ml aliquots of distilled water, and then air-dried. The product can be purified by dissolving it in a minimum amount of cyclohexane at room temperature and allowing the solution to evaporate under a stream of air. Yield 5.44 g (47%). Anal. Calcd. for AgCisHisOzFe C, 36.90 H, 3.10 Ag, 25.50 mol. wt., 423. Found C, 36.8 H, 3.22 Ag, 25.5 mol. wt., 435 (bromoform).f... 

Ni(COD)2 bis(cyclooctadiene)nickel(0) Ph3P-BC 1/1 adduct of triphenylphosphane and p-benzochi-none Me methyl Ph phenyl Tp. polymerization temperature melt temperature (DSC) rj in-tnnsic viscosity, measured in tetraline at MO C p. PE density. Polymerization conditions in situ catalyst in 50 mL toluene, solvent cyclohexane, ethylene pressure 100 bar. 

With a similar approach, Fischer and coworkers entrapped Ru nanoparticles inside porous [Zn40(BDC)3] (MOF-5) by hydrogenolysis of the adsorbed volatile ruthenium species [Ru(COD)(COT)] (COD — 1,5-cyclooctadiene, COT = 1,3,5-cyclooctatriene) [17]. The included Ru nanoparticles had a size range of 1.5-1.7 nm, and the intact framework of MOF-5 was cmifirmed by different spectroscopic methods. The resulting solid Ru MOF-5 was tested for oxidation of benzyl alcohol however, only a modest conversion of 25% to benzyl aldehyde was obtained, and the XRD revealed the breakdown of the structure of MOF-5 as well as the loss of framework porosity. In contrast, the crystallinity of Ru(S>MOF-5 remained when it was used to catalyze the hydrogenation of benzene to cyclohexane with 25% conversion under 3 bar H2 at 75°C (Scheme 8). 

To an acid-washed, base-washed, 200-mL Schlenk flask was added the dienyne (665 mg, 1.60 mmol, 1 equiv). Under a positive nitrogen flow, freshly distilled cyclohexane (160 mL) and /m-(hexafluoroisopropyl) phosphite (170 mg, 0.319 mmol, 0.2 equiv) were added. 6is-l,5-Cyclooctadiene nickel (2.13 pL, 0.075 M in THF, 0.160 mmol, 0.1 equiv) was added, and the reaction was stirred at RT for 1 h. The clear solution slowly changed to a golden yellow solution that was then wanned to... 

Naturally occurring alkaloid anatoxin-a, known to induce respiratory paralysis and possessing an unusual 9-azabicyclo[4.2.1]nonane skeleton, was recently synthesized by Trost and Oslob via an asymmetric intramolecular allylic alkylation (Scheme 39). The alcohol 179, prepared from 4-bromo-l-butene and ethylformate, was efficiently converted to functionalized cyclooctadiene 180 within six steps. Asymmetric cyclization was performed with a catalytic amount of Pd(0) and several ligands to enhance the enantioselectivity. A new chiral ligand, the (5,5)-l-(2-diphenylphosphinobenzamido)-2-(2-pico-linamido)cyclohexane, (5,5)-182, was synthesized to alleviate the unfavorable steric interaction and induced under smooth conditions the formation of cyclic 181 in 90% yield and 88% ee. The ester 181 was then converted to the methyUcetone, which was desulfonated to give (-)-anatoxin-a. 

Under standard conditions all unsubstituted cycloolefins apart from cyclohexene are metathetically polymerizable (Table 4). In fact, polymers of (Z, )-cyclodeca-1,5-diene [251] or 1,3-cyclooctadiene [252] containing 1,7-octadiene units pinch off cyclohexene in the presence of suitable metathesis catalysts. But even cyclohexane has recently been oligomerized at lower temperature [253]. 

Cyclohexane and neohexene are converted to benzene and neohexane in the presence of [IrH2(Me2C0)2(PRj)2] bFe. Without neohexene, benzene and two equivalents cyclohexane are produced. The mechanism (Scheme 2A)is based on the isolated complexes (A) and (B). 1,5-cyclooctadiene is slowly converted to cyclooctene by Rhg(C0)ig in isopropanol, probably isomersiation to 1,4- and 1,3-cyclooctadiene.The oxidation of cis-(24) by cyclohexenone in the presence of RhH(PPhj)ij is faster than of trans-(24) due to steric interactions... 

X 10 for cyclohexene, 2.3 x 10 for 1,3-cyclooctadiene, 2.0 x 10 for cyclohexane all in M- s" from Ref. [288]. Rate constant for 2,5-dimethyl-2,4-hexadiene refers to cumyloxyl in benzene. From Table 3.9. From Ref. [215] in acetonitrile. From Ref. [256] in acetonitrile for cyclohexene see also Refs. [258,259]. From Ref. [33] see also Ref. [72] in isooctane. Calculated from fluorescence lifetime in neat ethanol based on a lifetime in gas phase of 1030 ns. "From Ref. [230] in benzene/di-tert-butoxyperoxide (1/2). "From Ref. [289] in benzene. °From Ref. [288] in chlorobenzene Ref. [290] in benzene/di-ferf-butoxyperoxide (1/2). Values for cumyloxyl radicals can be found in Refs. [288,291,292]. PFrom Ref. [74] in benzene. From Ref. [291] in benzene see also Refs. [74,293]. From Ref. [232] in benzene at 37°C. Value for diethylsulfide. From Ref. [294] in benzene." From Ref. [70] in neat acetone. For quenching of triplet acetone by n-propylamine and triethylamine in acetonitrile see also Refs. [172,271]. In the case of alkoxyl radicals the values for cumyloxyl radicals are reported. From Refs. [29,231] reaction with fert-butoxyl radicals in benzene/di-tert-butoxyperoxide (1/2). Values not reported in table n-propylamine 1.6 x 10 M s, diethylamine ... 

The photochemical reactions of substituted 1,2-cyclononadiene, 1-methyl-1,2-cyclononadiene 84, were also reported by Stierman and co-workers. Direct irradiation > 220 nm) of 84 in pentane solution affords seven isomers 85-91 as the primary products, along with the secondary product 92. Methyl derivative 84 seems to favor vinylcarbene intermediates, in contrast to the concerted reaction of 72. Benzene-sensitized irradiation of strained l-t-butyl-l,2-cyclooctadiene 93 affords the spiro compound 94 in the vapor phase, and irradiation (254 nm) of a dilute benzene solution of 93 yields 3-7-butylbicyclo[3.3.0]oct-2-ene 95 and 2-7-butyl-l,3-cyclooctadiene 96 in a 1 1 ratio.The difference in reactivity between the vapor phase and the solution is explained as follows the vapor-phase reaction proceeds through biradical 97, whereas selective hydrogen abstraction from C7 yields biradical 98 in solution. On the other hand, direct irradiation (254 nm) of 93 in cyclohexane solution affords five photoproducts 95, 96, and 99-101. 

Miranda etaL reported that irradiation (254-nm mercury lamp) of [3.2]PCP-2-one 16 in benzene led to [2.2] PCP 15 as the only product via acyl-alkyl biradical 32 and biradical 33. A laser-flash photolysis study (266 nm) of 16 in cyclohexane indicated that biradical 33 is detectable at room temperature and does not cleave to p-xylylene 35 but cycKzes to [2.2]PCP 15 or dimerizes to [2 ]PCP 34. Irradiation (laser, 308 nm) of a cyclohexane solution of 15 containing a triplet quencher (cyclooctadiene) showed two absorption maxima, which correspond to p-xylylene 35 and the hiradical 33. The cyclophanes [2 ]PCP 21 and [2 ]PCP 34 were formed by irradiation (laser, 248 or 266 nm) of cyclohexane solutions of [2.2]PCP 15. While the formation of 34 agrees well with the intermediacy of 33, the detection of [2 ] PCP 21 provided further evidence for the intermediacy of p-xylylene 35, which can couple either its tiimeric or tetrameric products. 

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