Butadiene cyclotrimerization

This article describes further progress in the chemistry of 7r-allylnickel compounds. First, preparative methods for 7r-allylnickel halides, alkoxides, amides, and alkyls are described. Next, some chemical properties of these compounds—e.g., a recently observed disproportionation reaction—are discussed. Then, the use of 7r-allylnickel halides as homogeneous catalysts is discussed. Whereas bis (7r-allyl) nickel is a catalyst for butadiene cyclotrimerization, 7r-allylnickel halides combined with Lewis acids, such... 

Cyclododecanone, which became the most accessible of medium-ring ketones following Wilke s discovery of the butadiene-cyclotrimerization process, is an important starting point for manufacture of the valuable musk ketones. Two syntheses of muscone, commencing from cyclododecanone are outlined below. The first synthesis, which emanated jointly from Eshenmoser s group in Zurich and laboratories of the Swiss perfume firm, Firmenich Cie., illustrates a three-carbon ring expansion reaction based on the widely applicable tosylhydrazone version of the oxidoketone— alkynone fragmentation. ... 

Pd-cataly2ed reactions of butadiene are different from those catalyzed by other transition metal complexes. Unlike Ni(0) catalysts, neither the well known cyclodimerization nor cyclotrimerization to form COD or CDT[1,2] takes place with Pd(0) catalysts. Pd(0) complexes catalyze two important reactions of conjugated dienes[3,4]. The first type is linear dimerization. The most characteristic and useful reaction of butadiene catalyzed by Pd(0) is dimerization with incorporation of nucleophiles. The bis-rr-allylpalladium complex 3 is believed to be an intermediate of 1,3,7-octatriene (7j and telomers 5 and 6[5,6]. The complex 3 is the resonance form of 2,5-divinylpalladacyclopentane (1) and pallada-3,7-cyclononadiene (2) formed by the oxidative cyclization of butadiene. The second reaction characteristic of Pd is the co-cyclization of butadiene with C = 0 bonds of aldehydes[7-9] and CO jlO] and C = N bonds of Schiff bases[ll] and isocyanate[12] to form the six-membered heterocyclic compounds 9 with two vinyl groups. The cyclization is explained by the insertion of these unsaturated bonds into the complex 1 to generate 8 and its reductive elimination to give 9. 

Scheme 5.2-24 Biphasic, Fe-catalyzed cyclotrimerization of butadiene in [BMIM][BF4],...

A number of compounds with this ring system (163), including dispiro derivatives, are formed by the catalytic cooligomerization of ketazines or aldazines with butadiene (Scheme 186)249 reactions of this type are analogous to the catalytic cyclotrimerization of butadiene to cyclodecatriene.250... 

The cyclotrimer products are liberated in subsequent, consecutive substitution steps with new butadiene, which is an exothermic reaction (AH) for expulsion of all-t-CDT by three /ran.v-butadienes along 8b —> l b. This process, however, is endergonic by 7 kcal mol-1 (AG) after entropic costs are taken into account. Therefore, 7b and 8b (stabilized by donors) are indicated to be likely candidates for isolable intermediates of the catalytic process, while the active catalyst l b, the intermediate species 2b, in particular, and other species will not be present in a sufficient concentration, since they are either too reactive or thermodynamically too unfavorable, for experimental characterization. Overall, the cyclotrimerization process is driven by a strong thermodynamic force with an exothermicity of —44.6 kcal mol-1 (AH for the process without a catalyst) for the fusion of three trans-butadiene to afford the favorable all-t-CDT. 

Unlike nickel catalysts, palladium catalysts undergo neither cyclodimerization nor cyclotrimerization to form COD or CDT. Only one paper by Chepaikin and Khidekel reported that a mixture of divinylcyclobu-tanes was obtained from butadiene using palladium salts with noncom-plexing anions such as perchlorate and boron tetrafluoride (15). This is a big difference between the catalyses of palladium and nickel. 

The patent literature contains several references to the use of sulfoxide complexes, usually generated in situ, as catalyst precursors in oligomerization and polymerization reactions. Thus, a system based upon bis(acrylonitrile)nickel(0> with added Me2SO or EtgSO is an effective cyclotrimerization catalyst for the conversion of butadiene to cyclo-1,5,-9-dodecatriene (44). A similar system based on titanium has also been reported (407). Nickel(II) sulfoxide complexes, again generated in situ, have been patented as catalyst precursors for the dimerization of pro-pene (151) and the higher olefins (152) in the presence of added alkyl aluminum compounds. 

Metal-catalyzed [4 + 2 + 2] cyclotrimerizations of either heteroatom-containing enyne 62 with 1,3-butadiene (Eq. 17) [42] or heteroatom-containing dienyne 64 with an alkyne (Eq. 18) [43] are effected by cationic rhodium complexes generated in situ from a chlo-rorhodium complex modified with silver salts. These processes afford eight-membered ring products 63 and 65, respectively. In both processes, the nature and amount of the silver salt profoundly affect the outcomes. 

Controlling Factors in Homo neous Tiansistion-Metal Catalysis Table 2.3-1. Cyclotrimerization of butadiene by means of Ni-, Ct- or Ti-catalysts ... 

In Scheme 2.3-3 some examples of the influence of DO/ACC-perturbations in and at the catalytically reacting tr-systems are given. It reveals the influence of CH3-or other alkyl-groups af the tr-system and that of the nitrogen atoms in the rr-system for the Ni-catalyzed 2 1 co-cyclotrimerization of butadiene with these substrates. 

The increased cooling efficiency of thin-walled reactors also has permitted the use of more volatile substrates in near molar quantities. (l-3 6-7 10-12-rj 2,6,10-Dodecatriene-l,12-diyl)nickel has been prepared in multiple gram quantities by cocondensation of nickel vapor and 1,3-butadiene. This method has provided a clean one-step route to this complex, which was first isolated and identified by Wilke et al.1 as an intermediate in the cyclotrimerization of 1,3-butadiene by nickel catalysts. 

Homogeneous nickel complexes proved to be versatile catalysts in dimerization and trimerization of dienes to yield different oligomeric products.46-55 Depending on the actual catalyst structure, nickel catalyzes the dimerization of 1,3-butadiene to yield isomeric octatrienes, and the cyclodimerization and cyclotrimerization to give 1,5-cyclooctadiene and all-trans-l,5,9-cyclododecatriene, respectively46 56 [Eq. (13.13)]. Ziegler-type complexes may be used to form cis,trans,trans-1,5,9-cyclododecatriene37,57 58 [Eq. (13.14)], which is an industrial intermediate ... 

The formation of CDT is suppressed if ethylene as well as butadiene is brought into contact with a naked-nickel catalyst. Depending on the reaction conditions, the product is a mixture of m,tram-1,5-cyclodecadiene (CDD) and 1,tram-4,9-decatriene (DT) (90). With equal concentration of butadiene and ethylene the co-oligomerization occurs some six times faster than the cyclotrimerization of butadiene to CDT. 

The dimerization and cyclotrimerization of butadiene are also catalyzed by titanium but are less well investigated. The Tiw Tj -octadienyl complex (22-XXXV) is isolable it catalyzes the dimerization of butadiene to the thermodynamically favored product, vinylcyclohexene.134... 

This article presents investigations on the elucidation of the reaction mechanism of this remarkable cyclo-oligomerization, as well as improvements in the cyclotrimerization and cyclodimerization of butadiene. 

Cyclodimerization and Cyclotrimerization of Butadiene 371 Table 2. The cyclodimerization of butadiene. 

After the pioneering work of Inoue et al. [7] and Musco [5], the most detailed study of the cyclotrimerization of butadiene and CO2 has been carried out by Behr using catalysts formed in situ from Pd(acac)2 (acac = acetylacetonate) and three equivalents of a suitable phosphine ligand [4]. 

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