As-Cyclododecene

Some novel bicyclic pyrylium salts arise when a dicarboxylic acid derivative is used. For example, although decanedioyl chloride did not diacylate isobutene, possibly because of strain inherent in the expected product, 1,12-dodecanedioyl chloride gave a very low yield of the pyrylium salt (658) (62T1079). A dilute solution of the reactants in nitromethane was used in order to favour the intramolecular reaction. In a similar vein, a macrocyclic alkene, such as cyclododecene, undergoes diacylation to the bicyclic salt (659) (68TL4643), whilst... 

The use of diimide provides a particularly convenient and general method for the selective reduction of trans double bonds of medium ring systems. The as-cyclododecene produced in this selective reduction is thermodynamically less stable than the corresponding ira j-isomer. ... 

Diacylation of cycloalkenes such as cyclododecene and cyclodecene affords the corresponding pyrylium salts.° Whereas the diacetylation of cyclododecene (29) with acetic anhydride in the presence of 70% perchloric acid proceeds smoothly in satisfactory yield, the analogous reaction with cyclodecene (31) succeeds only with sulfoacetic acid (prepared by heating acetic anhydride with sulfuric acid under carefully controlled conditions), and the yield is lower than 10%. The central CH2 groups of the resulting 9,1 l-dimethyl-[7]-(2,6)-pyrylophanium perchlorate (32) and of the... 

Cyclododecene (cis and tians) was similady tiansformed to the cyclic enone, which is an impoitant intermediate in the preparation of perfumary products, such as muscone [541 -91 -3J. 

Another process for the production of dodecanedioic acid is by oxidation of cyclododecene using a two-phase system in which mthenium tetroxide serves as the oxidizing agent in the organic phase, and is regenerated in the second phase, an aqueous phase containing cerium(IV) ions (75). 

E-Cyclooctene is also significantly straine4 but less so than -cycloheptene. As the ring size is increased, the amount of strain decreases. The. E-isomers of both cyclononene and cyclodecene are less stable than the corresponding Z-isomers, but for cycloundecene and cyclododecene, the E-isomers are the more stable. Table 3.10 gives data concerning the relative stability of the C7 through C12 cycloalkenes. 

Mikroreaktoren sind so klein wie ein Fingerhut, Handdsblatt, May 1998 Steep progress in microelectronics, sensor and analytical techniques in the past transport intensification for catalysis first catalytic micro reactors available partial oxidation to acrolein partial hydrogenation to cyclododecene anodically oxidized catalyst supports as alternatives to non-porous supports study group on micro reactors at Dechema safety, selectivity, high pressure exclusion of using particle solutions limited experience with lifetime of micro reactors [236],... 

The very unusual selective hydrogenation of ,/3-unsaturated aldehydes to the unsaturated alcohols, Eq. (30), has been accomplished using [RhCl(CO)2]2 in the presence of tertiary amines under oxo conditions (162). RhCl(PPh3)3 systems under similar conditions reduce the olefinic bond (162), as do Co2(CO)8 systems in the presence of amines or phosphites (163). Further details on the versatile Rh(BH4)(amide)py2Cl2 systems (/, p. 280) have appeared (164, 165) ketones are also slowly hydrogenated (166), and 1,5,9-cyclododecatriene has been selectively reduced to cyclododecene (167). 

Use of molten salts as solvent allows easy separation of organic products by distillation (376), and in this way PtCl2 with tetraalkylammonium salts of SnCl3 and GeCl3 has been used to selectively hydrogenate 1,5,9-cyclododecatriene to cyclododecene the salts in this case act as both solvent and ligand (377). A molten salt medium has been used in a homogeneously catalyzed Fischer-Tropsch synthesis (see Section VI,B). 

As expected, although TS-1 is more active and selective in the epoxidation of linear alkenes (such as hex-l-ene and dodec-l-ene), the large-pore Ti-beta is more active in the case of the bulkier cyclohexene (TON of 14 v.v. 1 for TS-1) and cyclododecene (TON of 20 vs. 5 Table VII) (11). 

A new class of heterogeneous catalyst has emerged from the incorporation of mono- and bimetallic nanocolloids in the mesopores of MCM-41 or via the entrapment of pro-prepared colloidal metal in sol-gel materials [170-172], Noble metal nanoparticles containing Mex-MCM-41 were synthesized using surfactant stabilized palladium, iridium, and rhodium nanoparticles in the synthesis gel. The materials were characterized by a number of physical methods, showed that the nanoparticles were present inside the pores of MCM-41. They were found to be active catalysts in the hydrogenation of cyclic olefins such as cyclohexene, cyclooctene, cyclododecene, and... 

Gas chromatographic analyses are obtained at about 120° with a 2 m. X 7 mm. column packed with a suspension of 5% (by weight) of silver nitrate and 15% (by weight) of Carbowax 6000 (polyethylene glycol) on either Chromosorb P or Celite 545. With this column the relative retention times of the various possible components in the reaction mixture are cyclododecane, 1.00 trans,trans,trans-, S,9-cyc ododec tnene, 1.20 trans-cyclo-dodecene, 1.13 m-cyclododecene, 1.33 ci5,iraw5-l,5-cyclodode-cadiene, 1.51 m, m 5-/raw5-l,5,9-cyclododecatriene, 1.72. The reaction should be stopped when the rate of reduction of cis,trans-1,5-cyclododecadiene to cw-cyclododecene has become approximately equal to the rate of conversion of the as-monoolefin to cyclododecane. 

When the reaction has progressed to the desired stage (Note 6), the flow of air is stopped and the mixture is filtered. After the filtrate has been extracted with two 350-ml. portions of petroleum ether (b.p. 30-60°), the combined hydrocarbon extracts are washed successively with two 100-ml. portions of 2N hydrochloric acid and three 100-ml. portions of water. The petroleum ether is distilled from the solution, heated in a water bath, through a 60-cm. Vigreux column, and the residual liquid is distilled under reduced pressure. The fraction, b.p. 64-65° (1.0 mm.) or 132-134° (35 mm.), is collected as 39.5-52.0 g. (64-85%) of colorless liquid, 1.4846-1.4850. This distillation fraction contains (Note 6) 80-90% of the ci5-cyclododecene (51-76%) accompanied by 10-20% of a mixture of cyclododecane and ai,ira s-l,5-cyclododecadiene (Note 7). If desired, the cis-cyclododecene may be further purified by preparative chromatography or separation of the silver nitrate-olefin addition complex (Note 8). 

The behavior of dienes and polyenes - both open chain and cyclic - toward reduction depends especially on the respective positions of the double bonds. Carbon-carbon double bonds separated by at least one carbon atom behave as independent units and can be partly or completely reduced by catalytic hydrogenation or by diimide. cis, trans, /rani-l,5,9-Cyclododecatriene treated with hydrazine and air in the presence of copper sulfate (diimide in situ) gave cij-cyclododecene in 51-76% yield [269]. It appears as if the trans double bonds were reduced preferentially. 

The results confirm the previously reported low reactivity of cyclohexene when the catalyst is TS-1 and indicate that Ti-beta is active for the oxidation of cyclohexene and other bulky olefins. However, for cyclohexene and the linear olefins, the major reaction products formed in the presence of Ti-beta are glycols and glycol ethers, whereas in the presence of TS-I, epoxides are predominantly formed. Also in this case, the epoxides initially formed in the presence of Ti-beta undergo secondary reactions catalyzed by the acidic centers associated with the aluminum in the material, as previously seen for allyl alcohol and for the epoxidation of 1-butene on aluminum-containing TS-1 (Bellussi et al., 1991a). A different product composition was observed for cyclododecene,... 

Palladium deuteride 1 may act as an activator of C-H bonds at allylic positions and may form Jt-allyl palladium. Via the equilibrium between Jt-allyl palladium and alkene, H-D exchange will occur by C=C double bond migration. As shown in Scheme 5, cyclododecene was converted into the fully deuterated compound by treatment with hydrothermal deuterium oxide in the presence of Pd/C catalyst. Without Pd/C, no deuteration was observed under these reaction conditions [16]. 

In addition to performing acid/base catalysis, zeolite structures can serve as hosts for small metal particles. Transition metal ions, e.g., platinum, rhodium, can be ion exchanged into zeolites and then reduced to their zero valent state to yield zeolite encapsulated metal particles. Inside the zeolite structure, these particles can perform shape selective catalysis. Joh et al. (16) reported the shape selective hydrogenation of olefins by rhodium encapsulated in zeolite Y (specifically, cyclohexene and cyclododecene). Although both molecules can be hydrogenated by rhodium supported on nonmicroporous carbon, only cyclohexene can be hydrogenated by rhodium encapsulated in zeolite Y since cyclododecene is too large to adsorb into the pores of zeolite Y. 

Cyclododecyl phenyl tellurium treated with 30% hydrogen peroxide in tetrahydrofuran or with sodium periodate in water/tetrahydrofuran at 25° produced cis- and trans-cyclododecene as the main product and dodecanol and dodecanone as the by products1. The ratio of cis/ trans-cyc ododecene was determined by the amount of oxidant used. With one molar equivalent of sodium periodate, only tran.v-cyclododecene was formed1. 

The hydrogenation of 1,5,9-cyclododecatriene (1,5,9-CDT) to cyclododecadienes (CDD) and cyclododecene (CDE) proceeds much less selectively than in the case of 1,5-COD. This may be due to the fact that the three double bonds in 1,5,9-CDT cannot assist each other on adsorption to catalyst, as may be deduced from the inspection of its molecular model. Thus, it is expected that the difference in strength of adsorption or reactivity between 1,5,9-CDT and CDD or CDE would be considerably smaller than that between 1,5-COD and COE. Hanika et al. studied the hydrogenation of 1,5,9-... 

Scheme 3.11 Hydrogenation of 1,5,9-cyclododecatriene (CDT) via cyclododecadiene (CDD) and cyclododecene (CDE) as intermediates.

An IR spectrum of the product was identical to that of an authentic sample of frans-cyclododecene. The PMR spectrum of the product showed the 2 olefinic protons as a multiplet at 8 5.5, the 4 allylic protons as a multiplet at 2.2, and the remaining 16 protons as a peak centered at 1.4. 

In 1977, Sharpless proposed the intermediacy of a four-membered metal-lacycle in the oxidation of cyclododecene by Cr02Cl2.60 This was an attempt to explain a minor but primary product, in which an oxygen and a chlorine were added in a syn fashion to one face of the /3-bond. Later, this type of intermediate was incorporated into a new mechanism for osmylation,61 in which an initial [2 + 2] cycloaddition led to an osmaoxetane which in a second step underwent ring expansion to form the observed metal diolate product. At the time, the [2 + 2] process was viewed as a violation of orbital symmetry rules, and it was not until the extensive work in the 1970s and 1980s on cycloadditions to metal carbenes that a theoretical basis for such a process allowed its broader acceptance. 

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