Related carbonylation reactions

The M—Rj, bonds of A-cyclopentadienyl carbonyl alkyls are readily carbonylated, e.g. 

The acyl complexes may be decarbonylated but with more difficulty than the pentacarbonylmanganese acyls [198]. 

In this context, it is interesting to note that the insertion of sulphur dioxide into the Fe—R system has been observed, e.g. 

Direct carbonylation of non-carbonyl complexes with carbon monoxide has been shown for (PEt3)2MXR, where M = Pd or Pt, X = halogen and R = alkyl [2C0]. It seems reasonable that the reaction involves a five-co-ordinate transition state, viz. 

Square-planar palladium complexes are usually more labile than the platinum analogues, and in agreement with this trend carbonylation of the palladium-alkyls occurs more readily than with the platinum derivatives. 

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Metal-catalyzed reactions of CO with organic molecules have been under investigation since the late 1930s and early 1940s, when Roelen (/) discovered the hydroformylation reaction and Reppe (2) the acrylic acid synthesis and other related carbonylation reactions. These early studies of the carbonyla-tions of unsaturated hydrocarbons led to extremely useful syntheses of a variety of oxygenated products. Some of the reactions, however, suffered from the serious problem that they produced isomeric mixtures of products. For example, the cobalt-catalyzed hydroformylation of propylene gave mixtures of n-butyraldehyde and isobutyraldehyde. 

The reaction is highly catalytic in most instances and yields of substituted olefinic products are generally good to excellent at 100° or less. As in the related carbonylation reactions only aromatic, benzylic, and vinylic halides are useful in the reaction. Typical examples are shown in Table VIII. 

The hydroformylation of alkenes generally has been considered to be an industrial reaction unavailable to a laboratory scale process. Usually bench chemists are neither willing nor able to carry out such a reaction, particularly at the high pressures (200 bar) necessary for the hydrocarbonylation reactions utilizing a cobalt catalyst. (Most of the previous literature reports pressures in atmospheres or pounds per square inch. All pressures in this chapter are reported in bars (SI) the relationship is 14.696 p.s.i. = 1 atm = 101 325 Pa = 1.013 25 bar.) However, hydroformylation reactions with rhodium require much lower pressures and related carbonylation reactions can be carried out at 1-10 bar. Furthermore, pressure equipment is available from a variety of suppliers and costs less than a routine IR instrument. Provided a suitable pressure room is available, even the high pressure reactions can be carried out safely and easily. The hydroformylation of cyclohexene to cyclohexanecarbaldehyde using a rhodium catalyst is an Organic Syntheses preparation (see Section 4.5.2.5). 

Some related carbonylation reactions of nickel complexes have been postulated to proceed via Ni—H species (128), and reactions of acetylenes with iron carbonyls in alkaline solution (233, 234) maY proceed via Fe—H intermediates (249). 

By 1974 the latter reaction had been generalized, and a wide variety of organic halides and other related electrophiles including alkenyl and aryl halides had been used, most notably by Heck and co-workers. Also developed in his study was a related carbonylation reaction for the synthesis of amides. Use of organometals and metal hydrides in place of alcohols and amines most notably by Steffy and Stille further expanded the scope of Pd-catalyzed carbonylation. 

VI.2.1.1.2 Palladium-Catalyzed Hydrocarboxylation and Related Carbonylation Reactions of 7T-Bonded Compounds... 

Hydroformylation, the Water-gas Shift Reaction, Fisdier-Tropsch, and Related Carbonylation Reactions... 

Hydroformylation and Related Carbonylation Reactions.—Reviews on the synthesis of commercially important organic intermediates via rhodium-catalysed hydroformylation reactions, carbonylations with triarylphosphine-palladium catalysts, diene carbonylations, and heterogenized rhodium catalysts for methanol carbonylation have been published. 

E. Hydroformylation and related carbonylation reactions Treatment of olefins with carbon monoxide and hydrogen under pressure and in the presence of dicobalt octacarbonyl gives mainly aldehydes or ketones. Alcohols and paraffins are formed as by-products. The hydroformylation of olefins to aldehydes is of considerable industrial importance. The prediction that cobalt tetracarbonyl hydride was a catalyst in these reactions [93, 94] has been amply verified for example the stoicheio-metric hydroformylation of 1-pentene by HCo(CO)4 proceeds at room temperature giving isomeric alddiydes [95]. It has been shown that HCo(CO)4 is formed under the hig pressure (100 atm. 1 1 H2 CO) and temperature (100-300°) conditions used in hydroformylation reactions [95, 96]. 

Ali BE, Alper H (2002) Palladium-catalyzed hydrocarboxylation and related carbonylation reactions of 7c-bonded compounds. In Negishi E (ed) Handbook of organopalladium chemistry for organic synthesis, vol II. Wiley, New York... 

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