Frans-2-Octenal

To corroborate that the epimerization reaction is responsible for the stereoerrors in the polypropylene chain, we treated 1-octene with complex 14 activated with MAO. The reaction resulted in the quantitative formation of frans-2-octene. In addition, the reaction of allylbenzene with the system 11/MAO at room temperature produced 100% conversion of the former to trans-methylstyrene. The isomerization results indicate that during the polymerization, the metal center in 14 is also able to migrate through the growing polymer chain, inducing branching and additional environments for the methyl ligands (Scheme 2) [124]. 

In further optimizations, Beller and coworkers examined various benzyl amines as replacement for pyrrolidine in the FeCl3-H2pydic catalyst system. They found thatthe use of different benzyl amines resulted in higher yields and better selectivity for the formation of epoxides, predominantly from aliphatic alkenes [111]. As seen in Table 2.8, the epoxidation of trans-l,2-disubstituted alkenes such as frans-2-octene and fruns-5-decene resulted in high yields, whereas aliphatic terminal alkenes appear to be problematic substrates. The epoxidation of aromatic alkenes using this catalytic system gave similar results to those obtained using pyrrolidine as base. 

The Institut Fran ais du Petrole has developed and commercialized a process, named Dimersol X, based on a homogeneous catalyst, which selectively produces dimers from butenes. The low-branching octenes produced are good starting materials for isononanol production. This process is catalyzed by a system based on a nickel(II) salt, soluble in a paraffinic hydrocarbon, activated with an alkylalumini-um chloride derivative directly inside the dimerization reactor. The reaction is sec-... 

The formation of derivatives of 2,3,6,8-tetraazabicyclo-[3.2.1]3-octene (425) arises from an intramolecular nucleophilic addition to the nitrone group of hydra-zone (424). Compound (424) was prepared by reaction of 2-acyl-3-imidazoline-3-oxides (423) with hydrazine. From the cis- and frans-derivatives (424), exo- and enr/o-isomers (425) were obtained (Scheme 2.197). The reaction of intramolecular cyclization does not occur in cases with monosubstituted hydrazones (316). 

The new recycling concept was apphed to several C - C bond-forming reactions, for example, to the telomerization of butadiene with ethylene glycol or carbon dioxide, to the isomerizing hydroformylation of frans-4-octene and to the hydroamino-methylation of 1-octene with morpholine. 

Cyclodextrins are often used as inverse phase transfer catalysts [11-14]. They are able to intercalate hydrophobic substances and to transport them into a polar phase like water, where the reaction takes place. To study the influence of cyclodextrins on the isomerizing hydroformylation of frans-4-octene in the biphasic solvent system propylene carbonate/dodecane, the concentration of methylated /3-cyclodextrin was varied from 0.2 up to 2.0 mol.-% relative to the substrate frans-4-octene [24]. The results are given in Table 7. 

The isomerizing hydroformylation of frans-4-octene has been executed in PC/dodecane/p-xylene with varying compositions of the three solvents. The phase diagram with the corresponding working points is presented in Fig. 7. 

The hydroformylation was investigated at various compositions of the TMS system propylene carbonate/n-dodecane/N-octyl-2-pyrrohdone (16/63/21, 24/50/26, 36/36/28, 50/23/27, 63/13/24 wt. %). With increasing mass fraction of propylene carbonate the conversion of frans-4-octene can be increased from 92 to 98% while the selectivity to -nonanal decreases from 81 to 72%. In the same way the rhodium loss is reduced from 21 to 1% and the loss of phosphorous from 15 to 7% as compared to similar conditions with NOP. 

The variation of the cyclic carbonate revealed that with increasing polarity (decrease in carbon chain length) the conversion regarding frans-4-octene decreases from 100 to 94% and the selectivity to n-nonanal increases from 76 to 86%. This is accompanied with rising catalyst leaching which reflects again the increasing difference in HSP between the cyclic carbonate and the mediator (Table 10). 

TMS systems, which were used in the isomerizing hydroformylation of frans-4-octene, should be apphcable to hydroaminomethylation as well because the hydroformylation is the first step of the reaction. For this reason similar TMS systems were apphed in a first series of investigations [40]. Propylene carbonate (PC) was chosen as the polar solvent si for the catalyst and alkanes (an isomeric mixture of dodecane or n-hexane) were used as non-polar component s2. 1.4-Dioxane, different pyrrohdones [N-methylpyr-rolidone (NMP), JV-ethylpyrrohdone (NEP), M-cyclohexylpyrrolidone (NCP) AT-benzylpyrrolidone (NBP) and N-octylpyrrohdone (NOP)] or esters of lactic acid (ethyllactate and butyllactate) served as mediator s3. As a test reaction the hydroaminomethylation of 1-octene with morphohne was investigated (Scheme 7). 

After 20 h, conversion was found to be higher in SCCO2 than in toluene under similar reaction conditions (Table 2) [136]. This effect is more pronounced for internal olefins, such as frans-3-hexene, compared to terminal olefins, such as 1-octene. 

Recent studies [174] also focused on the influence of the Co/phosphine ratio on the catalytic performance of frans-Co2(CO)6[P(3 - FC6H4)3]2 8 with additional P(3 - FC6H4)3 in the hydroformylation of 1-octene in SCCO2. The results are summarized in Fig. 22. 

Olefin styrene, a-methylstyrene, frans-p-methylstyrene, 1-hexene, c/s and frans-4-octene, c-pentene, c-hexene, c-heptene, indene, 1,2-dihydronaphthalene... 

The first Ru-catalysed epoxidation was reported in 1983 by James et al. using RuBr(PPh3)(OEP)/PhlO/CH2Cl2 with styrene, norbomene and aT-stilbene in low yields cf. mech. Ch. 1 [23]. Eater work showed that fran -Ru(0)2(TMP)/02/CgHg catalysed aerobic alkene epoxidation of cyclo-octene, cis- and trans- -methylstyrenes and norbomene (Fig. 1.26) [24],... 

Exercise 11-12 a. Draw the structure and configuration of the product expected of the reaction between 1-bromo-1-hexyne and diethylborane, (C2H5)2BH. b. When the product is treated with sodium methoxide, NaOCH3, then with propanoic acid, frans-3-octene is formed, Show the steps involved in forming this frans-alkene. 

Iodine azide adds stereo- and regio-specifically to 2-cholestene giving a frans-diaxial adduct with azide at the 2-position, a consequence of attack by I from the less hindered face of the steroid. With 1-hexene the addition proceeds regiospecifically to yield the secondary azide, most likely via a three-mem-bered iodonium ion intermediate.111 With (Z)-2-octene, BrN3 addition gives a single adduct in 71% yield... 

Two remarkable intramolecular reorganizations of the Diels-Alder adducts of methyl 2-chloro-2-cyclopropylideneacetate (1-Me) onto furans should be mentioned here. In a reaction of 1-Me with 2,5-bis(trimethylsilyl)furan (263) the unstable adduct 264 underwent a spontaneous deprotection followed by ring opening to give the dioxospiro[2.5]octene derivative 265 (Scheme 76) [7 m]. The Pauson-Khand reaction of the transformed Diels-Alder adducts 70, 71 of 1-Me have been discussed above (Scheme 18), however, when the compounds endo,-exo-62 e were treated under Pauson-Khand conditions, but at higher temperature, the interesting Co2(CO)8-promoted stereoselective rearrangement, in the presence as well as in the absence of an alkyne component, has been observed. The cis- and frans-substituted 6-methylenespiro[2.4]hexanes 266 were isolated as main products in these reactions (Scheme 76) [19b]. 

The strained ds,frans-l,3-cyclooctadiene 1 cyclizes quantitatively at 80°C to the bicy-clo[4.2.0]octene 2 (equation 3). The higher homologue 3 exists in equilibrium with the bicyclic isomer 4 above 175 °C (equation 4). ... 

The phosphine 286 is easily alkylated to provide the Wittig intermediate 287 that eliminates in the usual stereospecific manner via the oxaphosphetane 288 and must therefore give the strained frans-cyclo-octene E-284, the smallest trans cycloalkene that is stable. It is also chiral.58... 

Grieco and coworkers have utilized intramolecular aldolization of keto aldehydes to form seven-mem-bered rings. In a synthesis of ( )-helenalin, keto aldehyde (54) was cyclized to aldol (55 equation 112).133 In a later modification of the basic approach, keto aldehyde (56) was cyclized to cycloheptenone (57 equation 113).134 The success of these cyclizations is related to the fact that the normally preferred five-membered ring closure would yield a strained frans-fused bicyclo[3.3.0]octene system.135... 

The model compound, frans-4-chloro-4-octene, was chosen because it possessed the —C1C=CH— group of polychloroprene, but without the repeating 1,5-diene structure of the polymer. The autoxidation was similar to that observed for polychloroprene, although no induction period was observed (cf. hexachlorobutadiene oxidation above). The evolution of HC1 was proportional to the square of the time, but the oxidation kinetics were approximated more closely by the equation... 

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