Carbonylation of butadiene

Adipic acid may be produced by a liquid-phase catalytic carbonylation of butadiene. A catalyst of RhCl2 and CH3I is used at approximately 220°C and 75 atmospheres. Adipic acid yield is about 49%. Both a-gul-taric acid (25%) and valeric acid (26%) are coproduced ... 

Simple carbonylation and dimerization-carbonylation of butadiene take place in alcohol depending on the catalytic species of palladium. When PdCl2 is used as a catalyst with or without PPh3, 3-pentenoate (72) is the sole product (74, 75). On the other hand, when Pd(OAc)2 is used with PPh3, the dimerization-carbonylation takes place to give 3,8-nona-dienoate (73) (76, 77). 

A patent claiming the following oxidative carbonylation of butadiene to give unsaturated mono- and diesters has been published (116) ... 

Because of its potential application to the synthesis of estersfor lubricating oils, the dimerization-carbonylation of butadiene has received special attention. Basic phosphines such as PBun3 and weakly basic tertiary amine solvents (quinoline, N, N-diethylaniline) were found to improve both the stability and activity of the catalyst system.S3° In a further report in which PPr 3 was used as phosphorus ligand it was found that the addition of maleic anhydride caused a marked increase in the catalytic activity. It was believed that through coordination it stabilized the palladium(O) complexes formed against precipitation as metal.s 1... 

Carbonylation of butadiene gives two different products, depending on the catalytic species. When PdCl2 is used in alcohol, 3-pentenoate (150) is obtained [73,74], Further carbonylation of 150, catalysed by cobalt carbonyl, affords the adipate 178 [75]. However, 3,8-nonadienoate (151) is obtained by dimerization and carbonylation when Pd(OAc)2 and Ph3P are used [76,77]. The presence of chloride ion firmly attached to Pd makes the difference. 

A most important application of butadiene carbonylations is BASF s development of a three-stage process for the synthesis of adipic acid from the butadiene-containing C4 cut [1] (eqs. (4) and (5)). Cobalt is the catalyst metal of choice for this process. The reaction takes place in two steps the first stage, which involves a lower temperature (100-140 °C), uses a fairly high concentration of HCo(CO)4 and pyridine as catalyst system to ensure rapid carbonylation of butadiene to give methyl pent-3-enoate in 90 % selectivity, thus avoiding typical side reactions such as dimerization and oligomerization. 

Carbonylation of butadiene in alcohol catalyzed by Pd(OAc)2/PPli3 affords 3,8-nonadienoate 142 in high yield52, 53. The synthesis of 2-decenedioic acid (144) (royal jelly acid) may be carried out as follows54 Carbonylation of 142 in alcohol... 

The carbonylation of butadiene, readily available from petroleum sources, yields a dicarbonylated adduct and dimer-carbonylated product, both desirable from a commercial standpoint. Palladium-catalyzed reactions yield monocarbonylated ... 

Process 8 in Figure 2.12 indicates an interesting approach. This process involves a two-step carbonylation of butadiene [155]. In the first step butadiene is reacted with carbon monoxide and methanol in the presence of dicobaltoctacarbonyl and a heterocyclic structure containing a tertiary nitrogen moiety (pyridines, picolines, quinoline, isoquinoline) ... 

It is well-established that either 3-pentenoate or 3,8-nonadienoate are obtained by the carbonylation of butadiene depending on the nature of the catalysts. So far no successful asymmetric carbonylation of prochiral dienes is known. Alper carried out enantioselective thiocarbonylation of prochiral dienes, such as 2-methyl-l,3-pentadiene (30), with thiophenol and obtained the, y-unsaturated thioester 31 with 89 % ee in 71 % yield using (/ , / )-DIOP as a chiral ligand [9]. 

Butadiene also is a suitable substrate for oxidative carbonylation. Patent literature describes the use of CO in conjunction with Pd-C, CUCI2, and 02. Another patent uses a quinone as reoxidant system and a compound of Mn or V as cocatalyst. An 89% selectivity of diethyl 3-hexenedioate and diethyl 2-hexenedioate is obtained. (Scheme 11) Molecular sieves have been claimed to improve oxidative carbonylation of butadiene in the presence of PdCl2, CUCI2, and oxygen. ... 

Palladium-phosphine complexes catalyse the carbonylation of butadiene with carbon monoxide and alcohols, when nona-3,8-dienoic acid esters are formed when the catalyst has halide co-ordinated to palladium, dimerization is suppressed, and pent-3-enoic acid esters are obtained (Scheme 33). 

Palladium acetate plus triphenylphosphine catalyse the dimerization and carbonylation of butadiene. The major product is octa-2,7-dien-l-ol, formed by dimerization of the butadiene on the palladium to form (112),... 

After separation by preparative GC, (162 a) was treated with osmium tetroxide and acid to afford brevicomin. Catalytic dimerization and carbonylation of butadiene by Byrom et al. (121), followed by reduction, epoxidation, and hydrolysis gave the alkenediol (166), which was cyclized catalytically to e /o-brevicomin (Scheme 33). A stereoselective synthesis of optically active (li ,7JR)-(+)-exo-brevicomin (150) from (2S,3S)-D-(—)-tartaric acid (167) has been achieved by Mori (122) (Scheme 34). 

Migration of a hydride ligand from Pd to a coordinated alkene (insertion of alkene) to form an alkyl ligand (alkylpalladium complex) (12) is a typical example of the a, /(-insertion of alkenes. In addition, many other un.saturated bonds such as in conjugated dienes, alkynes, CO2, and carbonyl groups, undergo the q, /(-insertion to Pd-X cr-bonds. The insertion of an internal alkyne to the Pd—C bond to form 13 can be understood as the c -carbopa-lladation of the alkyne. The insertion of butadiene into a Ph—Pd bond leads to the rr-allylpalladium complex 14. The insertion is usually highly stereospecific. 

The 3-alkyi-1,3-butadiene-2-carboxylate (2-vinylacrylate) 850 is obtained in a high yield by the carbonylation of the 2-alkyl-2,3-butadienyl carbonate 849 under mild conditions (room temperature, atm)[522]. The corresponding acids are obtained in moderate yields by the carbonylation of 2,3-alkadienyl alcohols under severe conditions (100 °C, 20 atm) using a cationic Pd catalyst and p-TsOH[523],... 

The carbo-Diels-Alder reaction of acrolein with butadiene (Scheme 8.1) has been the standard reaction studied by theoretical calculations in order to investigate the influence of Lewis acids on the reaction course and several papers deal with this reaction. As an extension of an ab-initio study of the carbo-Diels-Alder reaction of butadiene with acrolein [5], Houk et al. investigated the transition-state structures and the origins of selectivity of Lewis acid-catalyzed carbo-Diels-Alder reactions [6]. Four different transition-state structures were considered (Fig. 8.4). Acrolein can add either endo (N) or exo (X), in either s-cis (C) or s-trans (T), and the Lewis acid coordinates to the carbonyl in the molecular plane, either syn or anti to the alkene. 

The production of 1,4-butanediol (1,4-BDO) from propylene via the carbonylation of allyl acetate is noted in Chapter 8. 1,4-Butanediol from maleic anhydride is discussed later in this chapter. An alternative route for the diol is through the acetoxylation of butadiene with acetic acid followed by hydrogenation and hydrolysis. 

Ring-opening of diastereomerically pure vinylaziridine 131, prepared by azir-idination of butadiene with 3-acetoxyaminoquinazolinone 130 [52], yielded acetate 132 with inversion of configuration, together with amino alcohol 133 with retention (Scheme 2.34) [53]. The formation of 133 can be explained by assuming participation by the quinazolinone carbonyl oxygen, which produces an intramolecular reaction with the aziridine carbon with retention of configuration. 

Due to the retractive forces in stretched mbber, the aldehyde and zwitterion fragments are separated at the molecular-relaxation rate. Therefore, the ozonides and peroxides form at sites remote from the initial cleavage, and underlying mbber chains are exposed to ozone. These unstable ozonides and polymeric peroxides cleave to a variety of oxygenated products, such as acids, esters, ketones, and aldehydes, and also expose new mbber chains to the effects of ozone. The net result is that when mbber chains are cleaved, they retract in the direction of the stress and expose underlying unsaturation. Continuation of this process results in the formation of the characteristic ozone cracks. It should be noted that in the case of butadiene mbbers a small amount of cross-linking occurs during ozonation. This is considered to be due to the reaction between the biradical of the carbonyl oxide and the double bonds of the butadiene mbber [47]. 

The Co2(CO)g/pyridine system can catalyze carbomethoxylation of butadiene to methyl 3-pentenoate (Eq. 6.44) [80]. The reaction mechanism of the cobalt-catalyzed carbalkoxylation of olefins was investigated and the formation of a methoxycar-bonylcobalt species, MeOC(0)Co from a cobalt carbonyl complex with methanol as an intermediate is claimed [81, 82]. 

Extension to carbocyclization of butadiene telomerization using nitromethane as a trapping reagent is reported (Eq. 5.48).72 Palladium-catalyzed carbo-annulation of 1,3-dienes by aryl halides is also reported (Eq. 5.49).73 The nitro group is removed by radical denitration (see Section 7.2), or the nitroalkyl group is transformed into the carbonyl group via the Nef reaction (see Section 6.1). 

Hydroxycarbonylation and alkoxycarbonylation of alkenes catalyzed by metal catalyst have been studied for the synthesis of acids, esters, and related derivatives. Palladium systems in particular have been popular and their use in hydroxycarbonylation and alkoxycarbonylation reactions has been reviewed.625,626 The catalysts were mainly designed for the carbonylation of alkenes in the presence of alcohols in order to prepare carboxylic esters, but they also work well for synthesizing carboxylic acids or anhydrides.137 627 They have also been used as catalysts in many other carbonyl-based processes that are of interest to industry. The hydroxycarbonylation of butadiene, the dicarboxylation of alkenes, the carbonylation of alkenes, the carbonylation of benzyl- and aryl-halide compounds, and oxidative carbonylations have been reviewed.6 8 The Pd-catalyzed hydroxycarbonylation of alkenes has attracted considerable interest in recent years as a way of obtaining carboxylic acids. In general, in acidic media, palladium salts in the presence of mono- or bidentate phosphines afford a mixture of linear and branched acids (see Scheme 9). 

The carbonylation was explained by the following mechanism. Formation of dimeric 7r-allylic complex 20 from two moles of butadiene and the halide-free palladium species is followed by carbon monoxide insertion at the allylic position to give an acyl palladium complex which then collapses to give 3,8-nonadienoate by the attack of alcohol with regeneration of the zero-valent palladium phosphine complex. When halide ion is coordinated to palladium, the formation of the above dimeric 7r-allylic complex 20 is not possible, and only monomeric 7r-allylic complex 74 is formed. Carbon monoxide insertion then gives 3-pentenoate (72). 

Carbonylation of a mixture of allyl chloride and butadiene with PdCl2 was carried out, and 3,7-octadienoate (76) was obtained as one product (79, 80) ... 

A study of the reactions of butadiene, isoprene, or allene coordinated to nickel in a metallacycle, with carbonylic compounds, has been reported by Baker (example 11, Table IV). In the presence of phosphines, these metallacycles adopt a cr-allyl structure on one end and a ir-allyl structure on the other, as mentioned in Section II,A,1. The former is mainly attacked by aldehydes or electrophilic reagents in general, the latter by nucleophiles (C—H acids, see Table I, or amines, see Table IX). 

Finally, it should be noted that the synthesis of methyl 2,3-butadiene-l-carboxylate can be achieved by the palladium-catalyzed carbonylation of 1-bromoallene with carbon monoxide in methanol [25]. Similarly, 2,3-allenamides are accessible from bromoallenes, carbon monoxide and primary amines or ammonia [26]. 

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