Octenes, addition

The phosphinated ligands 135 and 136 prepared from poly(acrylic acid) and from poly(ethyleneimine), respectively, gave active hydroformylation catalysts in reaction with [Rh(acac)(CO)2]. Under the conditions of Table 4.6 low conversions were observed in aqueous/organic biphasic systems, due to the low solubility of 1-octene. Addition of a surfactant (SDS) or an organic co-solvent (MeOH) led to dramatic increases in the yield of aldehydes, revealing the high intrinsic activity of the catalyst [120]. 

If BrCCl3 is allowed to react with a 50 50 mixture of 1,3-butadiene and a simple alkene like 1-octene, addition occurs almost exclusively to the 1,3-butadiene. Evidently the CC1 radical adds much more rapidly to the conjugated diene than... 

To 147 g. (1.5 mole) of triethylborane, 7 in the reaction flask is added 2 ml. of tetraethyldiborane.8 At — 78°, 90 ml. (0.75 mole) of trichloroboranet is condensed in the supply cylinder. The supply cylinder is connected to the inlet tube, and trichloroborane vaporized by removal of the cooling bath is bubbled into the triethylborane at a rate such that the mixture warms to 40-60° (3-4 hours). Finally the nearly colorless mixture is allowed to cool to room temperature, and the inlet tube is replaced by a stopcock. 1-Octene (5 ml.) is added through it, and the mixture is stirred 1 hour at room temperature. (Instead of the 1-octene addition, ethylene can be bubbled through the mixture at room temperature for 1 hour.) The reflux condenser is replaced by a 30-cm. column packed with 3-mm. glass helices, and the mixture is distilled. ( Caution. A solvent-resistant grease such as Kel-F grease, available from the 3M Co., is required to resist the hot vapor.) After a few milliliters forerun (b.p. 30-80°), one obtains 230 g. (98% yield) of completely colorless chlorodiethylborane, b.p. 81°. 

A highly diastereoselective alkcnylation of c/s-4-cyclopentene-l,3>diols has been achieved with 0-protected (Z)-l-iodo-l-octen-3-ols and palladium catalyst (S. Torii, 1989). The ( )-isomers yielded 1 1 mixtures of diastcrcomcric products. The (Z)-alkenylpalladium intermediate is thought to undergo sy/i-addition to the less crowded face of the prochiral cyclopentene followed by syn-elimination of a hydropalladium intermediate. 

Out first example is 2-hydroxy-2-methyl-3-octanone. 3-Octanone can be purchased, but it would be difficult to differentiate the two activated methylene groups in alkylation and oxidation reactions. Usual syntheses of acyloins are based upon addition of terminal alkynes to ketones (disconnection 1 see p. 52). For syntheses of unsymmetrical 1,2-difunctional compounds it is often advisable to look also for reactive starting materials, which do already contain the right substitution pattern. In the present case it turns out that 3-hydroxy-3-methyl-2-butanone is an inexpensive commercial product. This molecule dictates disconnection 3. Another practical synthesis starts with acetone cyanohydrin and pentylmagnesium bromide (disconnection 2). Many 1,2-difunctional compounds are accessible via oxidation of C—C multiple bonds. In this case the target molecule may be obtained by simple permanganate oxidation of 2-methyl-2-octene, which may be synthesized by Wittig reaction (disconnection 1). 

Under CO pressure in alcohol, the reaction of alkenes and CCI4 proceeds to give branched esters. No carbonylation of CCI4 itself to give triichloroacetate under similar conditions is observed. The ester formation is e.xplained by a free radical mechanism. The carbonylation of l-octene and CCI4 in ethanol affords ethyl 2-(2,2,2-trichloroethyl)decanoate (924) as a main product and the simple addition product 925(774]. ... 

Unsaturated Hydrocarbons. Olefins from ethylene through octene have been converted into esters via acid-catalyzed nucleophilic addition. With ethylene and propjiene, only a single ester is produced using acetic acid, ethyl acetate and isopropyl acetate, respectively. With the butylenes, two products are possible j -butyl esters result from 1- and 2-butylenes, whereas tert-huty esters are obtained from isobutjiene. The C5 olefins give rise to three j iC-amyl esters and one /-amyl ester. As the carbon chain is lengthened, the reactivity of the olefin with organic acids increases. 

In 1980 the Goodyear company announced copolymers of cyclopentadiene, cyclo-octene or cyclo-octa-1,5-diene with the Diels-Alder addition product of hexachlorocyclopentadiene and cyclo-octa-1,5-diene. This material has been proposed as an alternative to the polychloroprenes, with lower ( 5°C), and superior ozone resistance... 

An alternative view of these addition reactions is that the rate-determining step is halide-assisted proton transfer, followed by capture of the carbocation, with or without rearrangement Bromide ion accelerates addition of HBr to 1-, 2-, and 4-octene in 20% trifluoroacetic acid in CH2CI2. In the same system, 3,3-dimethyl-1-butene shows substantial rearrangement Even 1- and 2-octene show some evidence of rearrangement, as detected by hydride shifts. These results can all be accoimted for by a halide-assisted protonation. The key intermediate in this mechanism is an ion sandwich. An estimation of the fate of the 2-octyl cation under these conditions has been made ... 

Reaction of 4-octyne with trifiuoroacetic acid in CH2CI2 containing 0.1-1.0A/Br leads mainly to Z-4-bromo-4-octene by an anti addition. The presence of Br greatly accelerates the reaction as compared to reaction with trifiuoroacetic acid alone, indicating the involvement of the Br in the rate-determining step. ... 

For this specific task, ionic liquids containing allcylaluminiums proved unsuitable, due to their strong isomerization activity [102]. Since, mechanistically, only the linkage of two 1-butene molecules can give rise to the formation of linear octenes, isomerization activity in the solvent inhibits the formation of the desired product. Therefore, slightly acidic chloroaluminate melts that would enable selective nickel catalysis without the addition of alkylaluminiums were developed [104]. It was found that an acidic chloroaluminate ionic liquid buffered with small amounts of weak organic bases provided a solvent that allowed a selective, biphasic reaction with [(H-COD)Ni(hfacac)]. 

In addition to its effect on stability, delocalization of the unpaired electron in the allyl radical has other chemical consequences. Because the unpaired electron is delocalized over both ends of the nr orbital system, reaction with Br2 can occur at either end. As a result, allylic bromination of an unsymmetrical alkene often leads to a mixture of products. For example, bromination of 1-octene gives a mixture of 3-bromo-l-octene and l-bromo-2-octene. The two products are not formed in equal amounts, however, because the intermediate allylic radical is... 

Addition of the anion of l-(diphenylphosphinyl)-2-octene to 4-/er/-butoxy-2-cyclopentenone occurs exclusively opposite to the rwr-butoxy moiety to give a mixture of. syn- and twr/ -adducls. As discussed above, the geometry of the alkcnc in the allylic moiety determines the relative configuration of the newly created stereogenic centers1. 

In a study concerned with the synthesis of prostaglandins, it was reported that the anion of 3-phenylsulfinyl-l-octene underwent addition to 2-cyclopentenone to give a y-1,4-adduct (57%), which appeared to be a single diastereomer by 13C NMR16... 

The addition of various Kolbe radicals generated from acetic acid, monochloro-acetic acid, trichloroacetic acid, oxalic acid, methyl adipate and methyl glutarate to acceptors such as ethylene, propylene, fluoroolefins and dimethyl maleate is reported in ref. [213]. Also the influence of reaction conditions (current density, olefin-type, olefin concentration) on the product yield and product ratios is individually discussed therein. The mechanism of the addition to ethylene is deduced from the results of adsorption and rotating ring disc studies. The findings demonstrate that the Kolbe radicals react in the surface layer with adsorbed ethylene [229]. In the oxidation of acetate in the presence of 1-octene at platinum and graphite anodes, products that originate from intermediate radicals and cations are observed [230]. 

Addition of CBr4 to a number of monomers including functional-substituted monomers (heptene-1, octene-1, styrene, and methylacrylate) has been performed in the presence of SmJ2 under mild conditions to give the adducts in high yield (ref. 4). 

Structurally, plastomers straddle the property range between elastomers and plastics. Plastomers inherently contain some level of crystallinity due to the predominant monomer in a crystalline sequence within the polymer chains. The most common type of this residual crystallinity is ethylene (for ethylene-predominant plastomers or E-plastomers) or isotactic propylene in meso (or m) sequences (for propylene-predominant plastomers or P-plastomers). Uninterrupted sequences of these monomers crystallize into periodic strucmres, which form crystalline lamellae. Plastomers contain in addition at least one monomer, which interrupts this sequencing of crystalline mers. This may be a monomer too large to fit into the crystal lattice. An example is the incorporation of 1-octene into a polyethylene chain. The residual hexyl side chain provides a site for the dislocation of the periodic structure required for crystals to be formed. Another example would be the incorporation of a stereo error in the insertion of propylene. Thus, a propylene insertion with an r dyad leads similarly to a dislocation in the periodic structure required for the formation of an iPP crystal. In uniformly back-mixed polymerization processes, with a single discrete polymerization catalyst, the incorporation of these intermptions is statistical and controlled by the kinetics of the polymerization process. These statistics are known as reactivity ratios. 

Among various methods to synthesize nanometer-sized particles [1-3], the liquid-phase reduction method as the novel synthesis method of metallic nanoparticles is one of the easiest procedures, since nanoparticles can be directly obtained from various precursor compounds soluble in a solvent [4], It has been reported that the synthesis of Ni nanoparticles with a diameter from 5 to lOnm and an amorphous-like structure by using this method and the promotion effect of Zn addition to Ni nanoparticles on the catalytic activity for 1-octene hydrogenation [4]. However, unsupported particles were found rather unstable because of its high surface activity to cause tremendous aggregation [5]. In order to solve this problem, their selective deposition onto support particles, such as metal oxides, has been investigated, and also their catalytic activities have been studied. 

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