Stoichiometric carbonylation

Diphenylcarbonate (DPC) is a key monomer for producing LEXAN polycarbonate resin by melt polymerization reaction of DPC with Bisphenol A. Currently, DPC is produced by General Electric Company (GE) in Cartagena, Spain, using a two-step process (Eq. 1) The stoichiometric carbonylation of... 

Kinetic studies of the stoichiometric carbonylation of [Ir(CO)2l3Me] were conducted to model the rate-determining step of the catalytic cycle [73,85]. The reaction can form both fac,cis and mer,trans isomers of [Ir(CO)2l3 (COMe)] (Scheme 13), the product ratio varying with the solvent and temperature used. An X-ray crystal structure was obtained for the fac,cis isomer. Carbonylation of [Ir(CO)2l3Me] is rather slow and requires temperatures > 80 °C in chlorinated solvents (e.g. PhCl). However, the presence of protic solvents (e.g. methanol) has a dramatic accelerating effect. This is interpreted in terms of the protic solvent aiding iodide dissociation by solvation. 

Scheldt and co-workers have reported the apphcation of silyl-protected thiazoUum carbinols as stoichiometric carbonyl anions for the intermolecnlar acylation of nilroalkenes [89]. While predominantly a discussion of racemic chemistry, a singular example illustrates that the newly formed stereocenter may be controlled by the addition of an equivalent of a chiral thionrea 136 with the desired product 135 formed in 74% ee Eq. 13. 

HRu(CO)s] is an interesting complex and has potential for a number of catalytic carbonylation reactions. However, the evidence for the presence of hydrogen is based mainly on chemical analysis which consistently shows the small hydrogen content. The stoichiometric carbonylation according to Reaction 4 and the IR of the crude carbonyl are... 

The stoichiometric carbonylation observed using [HRu(CO)3] and the proposed catalytic schemes all involve tricarbonyl species as the active catalyst the relatively high activity of Ru3(CO)i2 is consistent with this. The relative activity of the complexes for piperidine carbonylation is [HRu(CO)3L Ru3(CO)12 > [Ru(CO)2(OCOMe)]n. The major cause of the decrease in carbonylation rates is the accumulation of formyl product although the decrease in amine concentration is also a contributing factor. This catalyst poisoning is likely attributable to com-plexation to the ruthenium, presumably via the carbonyl grouping as commonly found for formamide ligands (26). The product could compete with either amine or CO for a metal coordination site. 

However, this reaction does not appear to have been reported. The stoichiometric carbonylation of phenylpalladium chloride, prepared in situ from phenyl-mercuric chloride, has been described600 ... 

Cobalt complexes have been used to catalyze the carbonylation of chloroarenes to the corresponding carboxylic acids and their esters (Sect. 3.3). Some complexes of cobalt in the oxidation state -1 activate the Ar-Cl bond via an SRN1-type mechanism [2] involving single electron transfer from the metal to chloro-arene, followed by elimination of Cl . The simplest Co(-I) carbonyl species, [Co(CO)4] , is not electron-rich enough to react with haloarenes. However, its reactivity has been shown to enhance tremendously in the presence of Caubere s complex bases, mixtures of NaH and NaOAlk [23,66,67]. For instance, the stoichiometric carbonylation of chlorobenzene has been performed with the... 

In the course of studying the stoichiometric, carbonylative synthesis of y-buty-rolactones from enones and a titanocene complex [37], it was observed that certain aryl enones could be cyclocarbonylated in a catalytic manner, Eq. (12) [38]. This success in effecting a titanocene-catalyzed cyclocarbonylation led to an examination of the analogous reaction with enyne substrates. Indeed, it was found that under similar conditions, a titanocene-catalyzed Pauson-Khand type cyclization was possible, Eq. (13) [36]. 

The resting state of the iridium catalyst is the anionic methyl complex, [Ir(CO)2l3Me], which is rapidly formed by oxidative addition of Mel to [I CO U]-- The complex is isolated as its cisfac isomer, and an X-ray crystal structure has been determined [144], Stoichiometric carbonylation of this species (Equation (13)) is regarded as the rate-determining step of the catalytic carbonylation cycle. 

SCHEME 14 Iodide loss mechanism for stoichiometric carbonylation of [lr(CO)2l3Me]-. 

Another example of a stoichiometric carbonyl-olefination reaction facilitated by a reagent which may be assumed to generate an intermediate tungsten carbene complex is shown in eqns. (7) and (8). The ketone can be added as soon as methane evolution has subsided (Kaufftnann 1986). 

Cobalt, nickel, iron, ruthenium, and rhodium carbonyls as well as palladium complexes are catalysts for hydrocarboxylation reactions and therefore reactions of olefins and acetylenes with CO and water, and also other carbonylation reactions. Analogously to hydroformylation reactions, better catalytic properties are shown by metal hydrido carbonyls having strong acidic properties. As in hydroformylation reactions, phosphine-carbonyl complexes of these metals are particularly active. Solvents for such reactions are alcohols, ketones, esters, pyridine, and acidic aqueous solutions. Stoichiometric carbonylation reaction by means of [Ni(CO)4] proceeds at atmospheric pressure at 308-353 K. In the presence of catalytic amounts of nickel carbonyl, this reaction is carried out at 390-490 K and 3 MPa. In the case of carbonylation which utilizes catalytic amounts of cobalt carbonyl, higher temperatures (up to 530 K) and higher pressures (3-90 MPa) are applied. Alkoxylcarbonylation reactions generally proceed under more drastic conditions than corresponding hydrocarboxylation reactions. 

Stoichiometric Carbonylation using Carbonyl Complexes 4.5.1 Iron and Cobalt Carbonyl Anions... 

The necessary temperatures and pressures of the carbonylation reactions are largely determined by the unsaturated starting material and the catalysts applied. In the pressureless stoichiometric carbonylation of acetylenes with Ni(CO)4, temperatures of 35 to 80 are sufficient. In the catalytic procedure with Ni(CO)4 temperatures of 120 to 220 °C and pressures around 30 atm are normally applied. In special cases lower temperatures may be used, e. g. in the acrylic acid and acrylic acid ester syntheses, which... 

The stoichiometric carbonylation of olefins and their derivatives may also be achieved without pressure at room temperature (in special cases even at lower temperatures). With catalytic amounts of cobalt hydrocarbonyl, temperatures between 100 and 260 °C and pressures from 30 upward to 900 atm are applied. In the carbonylation of saturated alcohols, cobalt catalysts are preferred, which are already highly active at 180 C, whereas nickel carbonyl requires a reaction temperature of 280 °C to give the same results [371]. 

It is known that in the stoichiometric carbonylation of PhC=CH and PhC=CPh the hydrogen atom and the later group are added via a cis addition. By this mechanism the essential role of a t-complex intermediate [7-22] in the stereospecific cis addition is clarified. The i-allyl nickel(II) halide complex (7t-C3H5NiX)2 reacts with carbon monoxide to give various products with different coreactants. 

Osakada K, Doh MK, Ozawa F, Yamamoto A. Catalytic and stoichiometric carbonyl-ation of p, y-unsaturated carboxylic acids to give cyclic anhydrides through intermediate palladium-containing cyclic esters. Organometallics. 1990 9 2197-2198. 

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