Alkenes reactions with carbon monoxide

Cobalt has an odd number of electrons, and does not form a simple carbonyl in oxidation state 0. However, carbonyls of formulae Co2(CO)g, Co4(CO)i2 and CoJCO),6 are known reduction of these by an alkali metal dissolved in liquid ammonia (p. 126) gives the ion [Co(CO)4] ". Both Co2(CO)g and [Co(CO)4]" are important as catalysts for organic syntheses. In the so-called oxo reaction, where an alkene reacts with carbon monoxide and hydrogen, under pressure, to give an aldehyde, dicobalt octacarbonyl is used as catalyst ... 

DiisononylPhthalate andDiisodeeylPhthalate. These primary plasticizers are produced by esterification of 0x0 alcohols of carbon chain length nine and ten. The 0x0 alcohols are produced through the carbonylation of alkenes (olefins). The carbonylation process (eq. 3) adds a carbon unit to an alkene chain by reaction with carbon monoxide and hydrogen with heat, pressure, and catalyst. In this way a Cg alkene is carbonylated to yield a alcohol a alkene is carbonylated to produce a C q alcohol. Due to the distribution of the C=C double bond ia the alkene and the varyiag effectiveness of certain catalysts, the position of the added carbon atom can vary and an isomer distribution is generally created ia such a reaction the nature of this distribution depends on the reaction conditions. Consequendy these alcohols are termed iso-alcohols and the subsequent phthalates iso-phthalates, an unfortunate designation ia view of possible confusion with esters of isophthaUc acid. 

Alkenes can be converted to succinic esters by reaction with carbon monoxide, an alcohol, and palladium chloride in the presence of mercuric chloride.1,12 The addition is mostly syn. In similar reaction, both terminal and internal alkynes can be converted to esters of maleic acid. 

Nitrenes are very reactive species and normally not isolated. A nitrene can be trapped by its reaction with carbon monoxide and alkenes. 

This reaction proceeds via transmetallation to generate an organopalladium intermediate which readily adds across the carbon-carbon double bond of the alkene. Rapid cis-palladium hydride / elimination generates the substituted alkene. Analogous reactions - with carbon monoxide are used to synthesize carbonyl compounds ... 

Similarly, alkenes react with carbon monoxide and methanol in the presence of palladium(II) chloride and a weak base (such as sodium acetate or butanoate) at 25 C and 3.03 bar of carbon monoxide pressure to form succinates. During this reaction palladium(O) is formed however, the reaction can be converted into a catalytic method if stoichiometric amounts of copper(II) chloride are added for reoxidation1 20. cis Addition is observed in the reaction of (E)- and (Z)-2-butene or 1-deuterated terminal alkenes19-22,39 as well as benzobicyclo[2.2.1]heptadienes40. In the absence of the base, methoxycarboxylation occurs (see Section 1.5.8.4.1.) as a trans processl9,20,22. 

Carboxylation of Alkanes and Alkenes. When alkenes react with carbon monoxide and water in the presence of strong mineral acids at elevated temperature and pressure, carboxylic acids are formed (87,88). The transformation is called the Koch reaction and may also be considered as hydrocarboxylation (eq. 61). Neocarboxylic acids with high selectivities are manufactured industrially with this process applying mixed Bronsted and Lewis acid catalysts (H2SO4, H3PO4, HF, and SbFg, BFg). 

The mechanism involves carbocation formation via protonation of the alkene (87,89) (eq. 62) followed by its reaction with carbon monoxide to form acyl cation (acylium ion) 23 (eq. 63). In the final step (eq. 64), 23 is quenched with water to 3ueld the product a-methyl carboxylic acid. 

Unactivated olefins are inert toward attack of nucleophiles. When complexed to palla-dium(II) salts, stabilized carbanions (p/(j, = 10-17) react intermolecularly with these olefinpalladium(II) complexes to generate alkylpalladium complexes. Alkylation occurs predominantly at the 2-position after a reductive or /3-elimination procedure or an insertion reaction with carbon monoxide. Nonstabilized carbanions attack the palladium directly, forming aUcylpalladium complexes that lead to alkene alkylation products at the 1-position. All these reactions required stoichiometric amounts of palladium salts. 

Later, it was found that alkenes underwent reaction with carbon monoxide (CO) and hydrogen (H2) in the presence of dicobalt octacarbonyl [Co2(CO)g] catalysts to produce aldehydes (i.e., the alkene has been hydroformylated). Presumably (Scheme 6.40) the process involves the coordination of the alkene to the metal (with loss of carbon monoxide, CO) followed by transfer of the carbonyl group to the alkene (with carbon cobalt bond formation) and subsequent reduction. As will be noted later (Chapter 9), aldehydes formed this way can be reduced to alcohols. Thus, additional important chemical intermdiates arise from this, the Oxo Reaction. ... 

Hydroformylation (Section 17 5) An industrial process for prepanng aldehydes (RCH2CH2CH=0) by the reaction of terminal alkenes (RCH=CH2) with carbon monoxide Hydrogenation (Section 6 1) Addition of H2 to a multiple bond... 

Treatment of the 1,2-oxazines 52 with carbon monoxide at 1000 psi in the presence of cobalt carbonyl brings about insertion of carbon monoxide to form the 1,3-oxazepines S3 <96TL2713>. A convenient route to P-lactams fused to oxepines is made available by alkene metathesis. Thus reaction of 4-acetoxyazetidin-2-one with ally alcohol in the presence of zinc acetate, followed by iV-allylation of the nitrogen affords the derivative 54 which cyclises by RCM to form the oxazepinone 55 <96CC2231>. The same communication describes a similar synthesis of 1,3-dioxepines. 

We have already reviewed the activation of alkenes, alkynes, and carbon monoxide towards nucleophilic attack. The heterolytic splitting of dihydrogen is also an example of this activation it will be discussed in Section 2.10. The reaction of nucleophiles with silanes co-ordinated to an electrophilic metal can be regarded as an example of activation towards nucleophilic attack (Figure 2.28). Complexes of Ir(III) and Pd(II) give t.o.f. for this reaction as high as 300,000 mol.mol. fh"1. 

There is a tendency toward alternation in the copolymerization of ethylene with carbon monoxide. Copolymerizations of carbon monoxide with tetrafluoroethylene, vinyl acetate, vinyl chloride, and acrylonitrile have been reported but with few details [Starkweather, 1987]. The reactions of alkenes with oxygen and quinones are not well defined in terms of the stoichiometry of the products. These reactions are better classified as retardation or inhibition reactions because of the very slow copolymerization rates (Sec. 3-7a). Other copolymerizations include the reaction of alkene monomers with sulfur and nitroso compounds [Green et al., 1967 Miyata and Sawada, 1988]. 

During a study of the origin of oxygenates in Fischer-Tropsch synthesis in the presence of a cobalt catalyst, Roelen observed the formation of propanal and 3-penta-none when ethylene was added to the feed.1 The process now termed hydroformylation or oxo reaction is the metal-catalyzed transformation of alkenes with carbon monoxide and hydrogen to form aldehydes ... 

The reaction is also called hydrocarboxylation. According to a later modification, the alkene first reacts with carbon monoxide in the presence of the acid to form an acyl cation, which then is hydrolyzed with water to give the carboxylic acid.97 The advantage of this two-step synthesis is that it requires only medium pressure (100 atm). Aqueous HF (85-95%) gave good results in the carboxylation of alkenes and cycloalkenes.98 Phosphoric acid is also effective in the carboxylation of terminal alkenes and isobutylene, but it causes substantial oligomerization as well.99 100 Neocarboxylic acids are manufactured industrially with this process (see Section 7.2.4). The addition may also be performed with formic acid as the source of CO (Koch-Haaf reaction).101 102 The mechanism involves carbocation formation via protonation of the alkene97 103 [Eq. (7.10)]. It then reacts with carbon monoxide... 

The conversion of alkenes to aldehydes with carbon monoxide and hydrogen in the presence of a cobalt catalyst is an important reaction (Section 16-9F) ... 

When the substrate contains two double bonds, either di- or tetra-carboxylatkm can be achieved.96 The reaction of 1,5-hexadiene at 5 bar CO gives the diester, while at 1-3 bar the tetraester is obtained (equation 72). These somewhat surprising results are consistent with a pressure-dependent competition of the alkene and carbon monoxide for coordination sites on palladium. Since 1,5-hexadiene is not easily displaced by CO, even at higher pressures, the carboxylation of one double bond is ensured. Competition of the resulting monoalkenic diester with carbon monoxide is dependent on the CO pressure, lower pressures allowing monoalkene coordination and thus dicarboxylation. 

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