1,5,9-Cyclododecatriene , synthesis

If it is now assumed that cyclododecatriene-nickel could be an intermediate in the cyclododecatriene synthesis, this compound should undergo displacement reactions with other electron donors and especially with butadiene. 

Anhydrous nickel chloride in chlorobenzene suspension is reduced in the presence of excess butadiene with aluminum triethyl. The product is the previously mentioned intermediate, I, of the cyclododecatriene synthesis. 

What metal 7c-complexes are active for a /./.. -cyclododecatriene synthesis by trimerization of butadiene ... 

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). 

Significant advances in organonickel chemistry followed the discovery of frtzws,fraws,fraws-(l,5,9-cyclododecatriene)nickel, Ni(cdt), and bis(l,5-cycloocta-diene)nickel Ni(cod)2 by Wilke et. al.1 In these and related compounds, in which only olefinic ligands are bonded to the nickel, the metal is especially reactive both in the synthesis of other compounds and in catalytic behavior. Extension of this chemistry to palladium and to platinum has hitherto been inhibited by the lack of convenient synthetic routes to zero-valent complexes of these metals in which mono- or diolefins are the only ligands. Here we described the synthesis of bis(l,5-cyclooctadiene)platinum, tris(ethylene)-platinum, and bis(ethylene)(tricyclohexylphosphine)platinum. The compound Pt(cod)2 (cod = 1,5-cyclooctadiene) was first reported by Muller and Goser,2 who prepared it by the following reaction sequence ... 

The starting point of this development was the discovery by Wilke (18) of the synthesis of cyclododecatriene-1,5,9 from butadiene using typical organometallic mixed catalysts. 

Interestingly a Ziegler Natta catalyst (Chapter 7) consisting of TiCU associated with an aluminium alkyl co-catalyst in a 1 1 molar ratio, polymerizes butadiene, but it is also able to afford cyclododecatriene provided that the TiCU/co-catalyst molar ratio is kept approximately to 0.1 instead of 1 [M. Rapoport and D. L. Sullivan, Can. Patent 1 055 052 (1979), to DuPont]. Although the mechanism is unclear, this is a good example of how delicate can be the modulation of a catalytic system for a selective synthesis. 

Three molecules of butadiene can be combined into 1,5,9-cyclododecatriene, using typical Ziegler-type catalysts. New TT-complex catalysts have been developed by which it is possible to direct the synthesis at will in direction of a trimerization or dimerization. 1,5-Cyclo-octadiene or 1,5,9-cyclododecatriene can be obtained in 95% yields. The catalysts can be isolated and are mostly crystalline—for instance, Ni-(0)-[P(CQH5)3]4 It has been possible to isolate a definite intermediate of the trimerization, the structure of which has been determined. Some reactions of this intermediate elucidate the mechanism of the trimerization. The cyclic olefins obtained from butadiene are valuable starting materials for the production of a-co difunctional compounds. 

The first active catalyst system found was prepared by reaction of nickel ace-tylacetonate with organoaluminum compounds in the presence of phenylacetylene. A dark red solution was obtained which reacted at 80° C. under pressure with butadiene to about 24% cyclo-octadiene, 8% vinylcyclohexene, and 63% all-tmns-cyclododecatriene. The component which stabilizes the reduced nickel was then changed systematically to discover the possibility of directing the synthesis at will in the direction of a trimerization or dimerization. Today we can synthesize cyclo-octadiene in yields of 95% or cyclododecatriene in similarly good yields only by altering the electron-donor molecules used in preparing the catalyst. 

The next step was to investigate the reaction of the centro-nickel compound wdth butadiene. When a solution of this compound is saturated with butadiene at room temperature, we observe that after a certain period the excess of butadiene has reacted with formation of cyclododecatriene and a new complex which can be isolated by removing the cyclododecatriene under high vacuum. The same catalytic reaction can be carried out by using bis (1,5-cyclo-octadiene) nickel as a catalyst. Cyclododecatriene synthesized in this way consists of three isomers. The main product is trans,trans,trans-cyc ododecdAx ene and the isolated by-products are transytrans,cis- and cis,cis,trans-cyc ododec3itnene. The latter compound is a new isomer, previously imknown (b.p.14 110° C., 1.5129). The synthesis of... 

Corey and Hamanaka - employed intramolecular allylic coupling in a novel synthesis of medium-size carbocyclic systems. The doubly allylic o.ai-dihulidc (I) on cyclization with nickel carbonyl gave as the chief product the ull-trum-dimethyl-cyclododecatriene (2). eccompenled by an liomar, probably fh, iran.s.tmns. 

Concerning other reactions that make use of nitrous oxide as the oxidant, a process developed by BASF is worth mentioning, which involves the synthesis of cyclododecanone, a raw material for Nylon-12 and Nylon 6-12 [12]. Cyclodode-canone is oxidized to 1,12-dodecanedioic acid by oxidative cleavage with nitric acid. It is currently made by a five-step sequence from cyclododecatriene. The first step of the new process is the synthesis of cyclododecatriene from butadiene, which is then reacted with nitrous oxide, to produce cyclododecadienone, which is finally hydrogenated to cyclododecanone. The yield to cyclododecanone is significantly higher than with the conventional process, waste is reduced and investment costs are lower. BASF already has a contracted customer and is building a plant due to come on stream in 2009. 

Metathesis technology enables the synthesis of many other high-purity olefins for the speciality chemicals market. Phillips have produced multi-ton quantities of hexa-1,5-diene via ethenolysis of cyclooctadiene and cyclododecatriene over a W03/Si02 catalyst reaction (9). High yields of deca-1,9-diene can be obtained from ethenolysis of cyclooctene (obtained by partial hydrogenation of readily available cyclooctadiene), reaction (10). Similarly, tetradeca-1,13-diene can be obtained via ethenolysis of cyclododecene (obtained from cyclododecatriene) (Banks 1982, 1984a). 

Q Butadiene trimerisation is carried out nowadays on an industrial scale by Evonik, Arkema, Ems-Chemie and Ube. Cyclododecatriene is the starting material for the synthesis of high-value polyamides Vestamicf. The worldwide production has a volume of around 100,000 tonnes. 

These nickel compounds have high reactivities and high selectivities to substrates and are easily handled in experimental operations. Then, these compounds are widely available as reagents and catalysts for organic syntheses [61-72]. In particular, the production of acrylic acid by Reppe reactions, the production of butene by the dimerization of ethylene, and the synthesis of 1,5-cyclooctadiene or 1,5,9-cyclododecatriene by the dimerization or trimerization of butadiene, are well known as reactions using nickel catalysts, shown in eqs. (19.35)-(i9-38) [61,65,72-77]. 

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