Butadiene with nickel

The interaction of butadiene with nickel afford a gray, intractable, and nonvolatile material together with traces of a volatile yellow oil-containing bis(crotyl)nickel. Further reaction of the nonvolatile fraction with butadiene gives a bis(allyl)-C12 nickel complex (IV) in good yield (709) ... 

Cyclodimerization of Butadiene with Nickel-ligand Catalystsa-b... 

Telomerization reactions of dienes are important. While cyclooligomerizations of butadienes with nickel catalysts are technically important for producing the precursors of polyamides or polyesters (cf. Section 2.3.6), the telomerization... 

Table 1. Composition of the oligomerization products of butadiene with nickel-ligand catalysts .

The mechanism of this reaction was studied by Tolstikov [69] using deuterated butadiene. With nickel catalysts, butadiene and acrylic ester form 2 1 adducts (Equation 58) [70]. 

Photodimerization of isoprene to 1,5-dimethylcyclo-octa-l,5-diene and 1,6-dimethylcyclo-octa-1,5-diene is discussed. Evidence has been presented for a multistep process in the oligomerization of butadienes with nickel... 

Reduced nickel salts in the presence of a large amount of phosphine catalyze the hydroaminahon of 1,3-butadiene with EtjNH (Eq. 4.44) [175, 176]. 

Scheme 6. Interplay of the C8- and C -production channels for the cyclo-oligomerization of 1,3-butadiene with zero valent PR3/P(OR)3-stabilized nickel complexes as the catalyst. Free energies (AG, AGJ in kcalmol-1) are given relative to the favorable rf-synrfiC A-cis isomer of 2a for catalysts bearing strong a-donor ligands namely I (L = PMe3), III (L = PPrj), VI (L = PBU3), and -acceptor ligands namely V (L = P(OMe)3), IV...

Linear oligomerization and telomerization of butadiene take place with nickel complexes in the presence of a proton source (7). In addition, cooligomerization of butadiene with functionalized olefins such as methacrylate is catalyzed by nickel complexes [Eq. (4)] (12, 13) ... 

Similar studies on the reactions of butadiene and bis(ir-allyl)palladium were carried out by Wilke and co-workers (4). Unlike the reactions with nickel complexes, no cyclization took place, and 1,6,10-dodecatriene... 

These telomerization reactions of butadiene with nucleophiles are also catalyzed by nickel complexes. For example, amines (18-23), active methylene compounds (23, 24), alcohols (25, 26), and phenol (27) react with butadiene. However, the selectivity and catalytic activity of nickel catalysts are lower than those of palladium catalysts. In addition, a mixture of monomeric and dimeric telomers is usually formed with nickel catalysts ... 

Unlike nickel Catalysts, palladium complexes do not catalyze the homo-cyclization reaction to give CDT or COD. The difference seems to be due to a different degree of hydride shift and atomic volume. With palladium catalysts, the hydride shift is easier, and hence linear oligomers are formed. The characteristic reaction catalyzed by palladium is the cocyclization of two moles of butadiene with one-hetero atom double bonds such as C=N and C=0 bonds to give six-membered rings with two vinyl groups (19) ... 

With nickel complexes, these cocyclizations are not possible. A related reaction is the cocyclization of butadiene with azines to give 12-mem-bered heterocyclic compounds 9 (11) [see Eq. (3)]. 

Butadiene-ethylene dimerization (example 3, Table II) has been shown to proceed via a croty 1-nickel complex formed by protonation (54). It should be observed at this point that it cannot be excluded that linear cooligomerization of butadiene with ethylene to give 1,4,9-decatriene... 

Codimerization of butadiene with dicyclopentadiene (example 8, Table II) was shown to proceed via a crotyl-nickel complex (62). Ring contraction of cyclooctadiene (example 10, Table II) appears to be a hydride promoted reaction. The hydride-promoted dimerization of norbomadiene to -toly 1 norbornene (example 9, Table II) appears to be quite different from dimerization via a metallacycle (see Table I, example 16). 

Baker has also reported the reaction of butadiene with phenylhydra-zones leading to azoalkenes (example 14, Table IV). This is also a Grig-nard-type reaction which is catalytic. Analogous results were obtained with methylhydrazones (136). A wider scope was recently attained by causing allylic esters to react with phenylhydrazones in the presence of zero-valent nickel complexes having trialkyl phosphites (example 15, Table IV). 

Predominantly cis-1,4-polybutadiene is produced by coordination polymerization with mixed catalysts.187,487,488 Three catalyst systems based on titanium, cobalt, or nickel are used in industrial practice. Iodine is an inevitable component in titanium-alkylaluminum sytems to get high cis content. Numerous different technologies are used 490,491 A unique process was developed by Snamprogetti employing a (Tr-allyl)uranium halide catalyst with a Lewis acid cocatalyst.492-494 This catalyst system produces poly butadiene with 1,4-ris content up to 99%. 

Under conditions similar to those for allyl halides, 1,4-dichlorobutene reacts with nickel carbonyl to give butadiene. However, a double insertion of acetylene and carbon monoxide can be successfully carried out using 4-chloro-2-buten-l-ol and generating hydrogen halide in situ with a weak acid inorganic halide combination, e.g., NaBr-H3P04 (58). 

Fig. 1. Rate of reaction of butadiene with varying ligand nickel concentration (84).

Using the nickel-tri(o-phenylphenyl)phosphite catalyst, the composition of the reaction product is markedly dependent on the extent of conversion of the butadiene. With a conversion of less than 85°, 1,2-divinylcyclo-butane (DVCB) is obtained in a yield of up to 40° At higher conversions DVCB catalytically rearranges to COD and VCH ( Table VI)... 

A reasonable mechanism for the co-oligomerization of butadiene with ethylene on a naked-nickel catalyst is shown in Eq. (49). Interaction of an ethylene molecule with the bis(7r-allyl) C8 chain produces a C,0 chain, containing both an alkyl- and a 7r-allylnickel group (XLVI). Coupling of the alkyl bond with the terminal atom of a m-Tr-allyl group or the terminal... 

Fig. 3. Volume contraction in the co-oligomerization of butadiene with 2-butyne (nickel-ligand catalyst) (94) I = P(C6H5)3, II = P(OC6H5)3.

We have already mentioned that the co-oligomerization of butadiene with ethylene leads to the formation of decatriene (DT) by a hydrogen-transfer process. The ratio of cyclized to open-chain product depends on the temperature and the nature of the ligand bonded to the nickel. An additional factor which affects the product distribution is the presence and nature of substituents on the olefin. Aryl and ester groups are particularly effective in promoting a hydrogen-transfer reaction, and are treated in detail below. 

The coupling of the unsubstituted carbon atom of the mono-olefin with the Cs chain, which was observed in the co-oligomerization of styrene with butadiene, and of acrylic esters with butadiene, is not, however, a general phenomenon. For example, the co-oligomerization of 1-decene with butadiene using nickel-tricyclohexylphosphine as catalyst leads (after... 

Our experimental finding supports the view that the active site of butadiene polymerization in the presence of bis(7r-crotylnickel iodide) is the complex with nickel bound to iodide. Thus, the butadiene addition across syn-7r-allyllic bond produces trans-1,4-polybutadiene. 

Both di- and trimerization of butadiene with soluble nickel catalysts are well-established homogeneous catalytic reactions. The precatalyst having nickel in the zero oxidation state may be generated in many ways. Reduction of a Ni2+ salt or a coordination complex such as Ni(acac)2 (acac = acetylacetonate) with alkyl aluminum reagent in the presence of butadiene and a suitable tertiary phosphine is the preferred method. The nature of the phosphine ligand plays an important role in determining both the activity and selectivity of the catalytic... 

In butadiene di- and dimerization with nickel catalyst and (o-PhCd 1,0)3P as a stabilizing ligand, the yields of cyclo-octadiene and cyclo-dodecatriene... 

Successful development of the asymmetric hydrocyanation reaction may provide a versatile route to chiral nitriles, amines, and acids. As we have seen, the mechanistic details of the hydrocyanation reaction of butadiene with zero-valent nickel complexes are well established. By using a nickel complex of a chiral bidentate phosphinite ligand, 9.53, good conversion and enantioselectiv-ity (>85% e.e.) for the hydrocyanation of 6-methoxy 2-vinyl naphthalene have been obtained. 

Later studies by Wells and co-workers, however, showed that the translcis ratios of the 2-butene formed from hydrogenation of 1,3-butadiene over nickel and cobalt catalysts depended on the reduction temperature employed for catalyst activation. High translcis ratios of 3.5-8 were obtained over the catalyst reduced at 400°C, while the ratios decreased to 2 with the catalysts activated below 350°C.119,120 The characteristic properties of the nickel and cobalt catalysts activated at 400°C were attributed to a modification of the catalysts caused by the sulfur compounds contained in the support that occurred at such a high reduction temperature as 400°C.121... 

Nickel bromide also is more effective than nickel(ll) acetylacetonate in the condensation of benzyl methyl ketone with 1,3-butadiene. The reaction of this activt methylene compound with 1,3-butadiene with the NiBr2 system with sodium phenoxidt... 

The hydrogenations of allenes may proceed through allylic intermediates. The distribution of products formed during the reaction of 1,2-butadiene with D2 depends on the particular nickel catalyst used. Reactions on the more selective catalysts (Ni powder, Ni/Si02) are presumed to proceed mainly via vinyl intermediates reactions on the less selective catalysts (Ni/AhOs) proceed via allylic intermediates (equation 34). A similar dichotomy of mechanisms is assumed to characterize reactions on Pd. 

Diene Cyclization. In 1952 Reed (157) discovered the catalytic dimerization of butadiene with Reppe catalyst in the presence of acetylene. Important results were obtained by Wilke (200) in the cyclization of butadiene with a nickel(0) catalyst. With bis-7r-allylnickel, biscyclo-i,5-octadienenickel, or cyclododecatrienenickel, he obtained the trimerization of butadiene to cyclododecatetraene while, with a catalyst of the type Ni(PR3)4, in which perhaps one coordination site cannot be replaced, he obtained the dimerization to cycloocta-l,5-diene. The mechanism of these reactions, in which 7r-allyl systems can be in equilibrium with o--7r-allyl systems (Figure 7), have been proved by Wilke and co-workers who isolated the intermediate compounds. It is worth noting that all these catalysts have ligands of weak -acceptor character which are labile and do not prevent butadiene from coordinating. The presence of weak t acceptors on the nickel tends to favor the structure of the diene, as was emphasized by Mason (112). 

Two isomeric 1,5,9-cyclododecatrienes, namely, trans,trans,cis-CijH 18 (XLVI) and trans,trans,trans-CuHis (XLVII), are formed in good yield by the cyclic trimerization of butadiene using certain Ziegler-type catalysts 247, 250, 251, 252). The formation of these 12-membered ring hydrocarbons probably proceeds via metal 7r-complexed intermediates. When the cyclic triene (XLVII) is treated with nickel acetylacetonate and... 

Catalysts from Group VIII metals have given unsatisfactory results. In the polymerization of butadiene with soluble cobalt catalysts tritium is not incorporated when dry active methanol is employed [115], although it is combined when it has not been specially dried [117, 118]. Alkoxyl groups have been found when using dry alcohol [115, 119] but the reaction is apparently slow and not suited to quantitative work [119]. Side reactions result in the incorporation of tritium into the polymer other than by termination of active chains [118], probably from the addition of hydrogen chloride produced by reaction of the alcohol with the aluminium diethyl chloride [108], Complexes of nickel, rhodium and ruthenium will polymerize butadiene in alcohol solution [7, 120], and with these it has not been possible to determine active site concentrations directly. 

In 1954, Re (5) reported that it is possible to synthesize 1,5-cyclo-octadiene from butadiene with Reppe catalysts obtained from nickel carbonyl. The yields were in the range of 30 to 40%. Recently, some patents granted to the Cities Service Co. (1,6) show that great improvements have been made in this process also. 

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