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And carbonylation of aryl halides

Subsequent studies on the reactivities of neutral and cationic alkyl- and aryl- palladium complexes revealed that the creation of a vacant site adjacent to the alkyl or aryl ligand causes marked enhancement in reactivity toward j8-hydrogen migration. The implications of these results on the fundamental processes of the transition metal alkyls and aryls with the mechanisms of Pd-catalyzed organic synthesis, such as arylation of olefins and carbonylation of aryl halides, have been discussed. [Pg.89]

A number of Pd or Cu catalysts bearing NHC ligands have been prepared for carbonylation of aryl halides. Nacci and co-workers synthesised the benzothiazole carbene ligated Pd complex 32 (Fig. 9.6) and tested it for aryl halide carbonylation... [Pg.226]

The palladium-catalyzed carbonylation of aryl halides in the presence of various nucleophiles is a convenient method for synthesizing various aromatic carbonyl compounds (e.g., acids, esters, amides, thioesters, aldehydes, and ketones). Aromatic acids bearing different aromatic fragments and having various substituents on the benzene ring have been prepared from aryl iodides at room temperature under 1 atm... [Pg.184]

Scheme 5. Palladium-catalyzed carbonylations of aryl halides and pseudohalides... Scheme 5. Palladium-catalyzed carbonylations of aryl halides and pseudohalides...
For the preparation of a-ketoamides, palladium-catalyzed double carbonylation of aryl halides with carbon monoxide and secondary amines is also a useful reaction Kobayashi, T. Tanaka, M. J. Organomet. Chem. 1982, 233, C64 Ozawa, F. Soyama, H. Yamamoto, T. Yamamoto, A. Tetrahedron Lett. 1982, 23, 3383. [Pg.233]

Ikariya and co-workers reported an efficient palladium-catalyzed carbonylation of aryl halides in sc C02 (eq. 2.10) (Kayaki et al., 1999). 2-Iodobenzyl alcohol was converted to the phthalide in the presence of PdCl2L2 [L = PMe3, PPh3, MeCN, P(OEt)3, P(OPh)3, PPh(OMe)2, PPh2(OMe)] with higher rates in sc C02 than in toluene. [Pg.33]

Aromatic carboxylic acids, a,/f-unsaturated carboxylic acids, their esters, amides, aldehydes and ketones, are prepared by the carbonylation of aryl halides and alkenyl halides. Pd, Rh, Fe, Ni and Co catalysts are used under different conditions. Among them, the Pd-catalysed carbonylations proceed conveniently under mild conditions in the presence of bases such as K2CO3 and Et3N. The extremely high toxicity of Ni(CO)4 almost prohibits the use of Ni catalysts in laboratories. The Pd-catalysed carbonylations are summarized in Scheme 3.9 [215], The reaction is explained by the oxidative addition of halides, and insertion of CO to form acylpalladium halides 440. Acids, esters, and amides are formed by the nucleophilic attack of water, alcohols and amines to 440. Transmetallation with hydrides and reductive elimination afford aldehydes 441. Ketones 442 are produced by transmetallation with alkylmetal reagents and reductive elimination. [Pg.85]

As with ester formation, carbonylation of aryl halides under amide-forming conditions and high carbon monoxide pressures leads to synthetically useful yields of a-ketoamides via double carbonylation916- 21. In these reactions the amine must be a fairly strong nucleophile and it is noteworthy that primary amines often give imines as the final product. Aryl chlorides do not normally undergo this reaction but specialized palladium catalysts may facilitate this process890. Alternatively, reaction may be possible via a first-formed... [Pg.756]

Thus, it has been shown that Co(CO)4 ion is a good nucleophile for the catalytic carbonylation of aryl halides in the presence of the electron donor NaH—RONa associate in THF and under photostimulation (equation 113)210. [Pg.1439]

A novel method was reported for the carbonylation of aryl halides by cobalt salt catalysts, such as Co(OAc)2, CoCl2, C0SO4, Co(OH)2, Co(OH)3, CoO and Co203 in an aqueous alkaline solution and under irradiation214. [Pg.1440]

One of the most interesting applications of the photostimulated carbonylation of aryl halides by Co(CO)4 ions under phase-transfer catalysis conditions is the synthesis of benzolactams and lactones 293 starting from aryl halides bearing amino or hydroxy groups on a side chain ortho to the halogen (equation 180)212. [Pg.1465]

In contrast, nucleophilic attack at an sp -carbon center with anionic 18-electron species like [Co(CO)4] and [Fe(CO)4] usually fails to activate aromatic or vinylic halides. Thus, catalytic carbonylations of aryl halides are initiated by oxidative addition of a C-X bond to an electronically unsaturated metal complex, normally a palladium [7], cobalt [8] or nickel complex [9]. The rate of this oxidative addition decreases along the sequence... [Pg.146]

The Pd-catalyzed carbonylation of aryl halides (cf Section 2.1.2) occurs with high turnover numbers and reaction rates in SCCO2 as the solvent using standard precursor complexes and commercially available phosphine or phosphite ligands [30]. The generally better performance of the phosphite-based catalysts was attributed to their better solubility in the reaction mixture, but the formation of Pd carbonyl complexes was also mentioned as a possibility. The [Ni(cod)2]/dppb system (dppb = l,4-bis(diphenylphosphino)butane) was investigated in an early study as a catalyst for the synthesis of pyrones from alkynes and CO2 under conditions beyond the critical data of carbon dioxide [31]. Replacing dppb with PMcs results in a system with better solubility and catalytic performance, albeit catalyst deactivation remains a problem [3 c, 15]. [Pg.857]

Reductive carbonylations of aryl halides to benzaldehydes, amidocarbonylations, and double carbonylations of C—X bonds are of interest in industry. [Pg.612]

The carbonylation of aryl halides with alcohols and amines catalysed by palladium complexes with triphenylphosphine ligand is the convergent and direct route to the synthesis of aromatic esters as well as aromatic amides. Even though these palladium complexes are widely employed as the best catalytic system, those catalysts are difficult to separate and reuse for the reaction without further processing. The major drawbacks are oxidation of triphenylphosphine to phosphine oxide, reduction of palladium complex to metal and termination of the catalytic cycle. The phosphine-free, thermally stable and air resistant catalyst (1) containing a carbon-palladium covalent bond (Figure 12.3) has been found to be a highly selective and efficient catalyst for the carbonylation of aryl iodides.[1]... [Pg.244]

Reaction medium. By virtue of its attributes supercritical carbon dioxide deserves its increasing applications as a reaction medium in synthesis. These include epoxidation" with oxygen and PhCHO, rhodium-catalyzed hydroboration, Pd(0)-catalyzed 1,4-hydroarylation of enones" and Heck reaction in the presence of Pd-C," carbonylation of aryl halides, Glaser coupling of 1-alkynes (mediated by CuCy using a solid ba.se (NaOAc)," as well as seandium(III) perfluorooctanesulfonate-catalyzed Diels-Alder and hetero-Diels-Alder reaetions. ... [Pg.87]

The carbonylation of aryl halides was performed with [diiodobis(3-methyl-2(3H)-benzothiazolylidene)palladium] immobilized in tetrabutylammonium bromide (melt), [G4GiIm]BF4, [G4CiIm]Cl, [G4CiIm]Br, and tricaprylmethyl-ammonium chloride (aliquat). Palladium acetate associated with phosphines immobilized in [C4GiIm][PF6] or [G4CiIm]BF4 catalyze hydroxycarbonylation of aryl halides and benzyl chloride derivatives (Scheme 19), and the acids are separated by extraction with water. ... [Pg.863]

A well-established preparative method of alkynyl ketones 110 is the Sonogashira-type carbonylation of aryl halides in the presence of terminal alkynes. (Trimethylsi-lyOpyridylethyne (111), deprotected in situ, reacted with 3-iodotoluene and CO to give the alkynyl m-tolyl ketone 112 using DPPF as a hgand. Pd-catalyzed reductive cyclization of 112 using HCO2H afforded the 1,8-naphthyridine 113 [48]. [Pg.281]

Cal, M. and Wang, P. (1998) Use of phase-transfer catalysis in palladium-catalyzed Heck carbonylation of aryl halides. Jiangxi Shifan Daxue Xuebao, Ziran Kexueban, 22, 231. ... [Pg.528]

Cunico and Maity published another example of palladium-catalyzed CO-free carbonylation of aryl halides [121]. Depending on the substrate, 2 mol% of either Pd(PPh3)4 or Pd(P Bu3)2 was used to catalyze the reaction of heteroaryl and aryl bromides with A,A -dimethyl-carbamoyl(trimethyl)silane (Scheme 2.10). Tertiary amides were prepared in good yields by direct carbamoylation under their conditions. Remarkably, chlorobenzene, 1-chloro -methoxybenzene, and iodoben-zene gave the desired products in 74, 78, and 60 % yields, respectively. [Pg.21]

Notably, the catalyst system is currently used on multi-1,000 kg-scale. The efficiency and easy handling properties (stable to air and moisture) make this the first industrial palladium-catalyzed reductive carbonylation of aryl halides. At this point it is important to note that applied homogeneous catalysis benefits significantly from advancements in the area of organometallic chemistry. Hence, the mechanistic understanding of elementary steps and the synthesis of new organometallic compounds provide a valuable source for inspiration for new catalysts. [Pg.60]

The first palladium-catalyzed carbonylations of aryl halides were published in 1974 and 1975 (Equation 17.59). ° Heck first reported the synthesis of benzoates by the reaction of an aryl iodide, carbon monoxide, and an alcohol in the presence of a tertiary amine and catalytic amoimts of the combination of palladium acetate and triphenylphosphine. Concurrently, he reported the synthesis of benzamides from an aryl iodide, carbon monoxide, a primary amine, and a tertiary amine as base catalyzed by the same type of palladium complex. The related reactions of vinyl halides were also reported, and these reactions occurred with retention of the olefin geometry. ... [Pg.795]

The reactions of aryl halides with carbon monoxide and either alcohols or amines to form esters or amides occur by two related yet distinct mechanistic pathways. These pathways are related to the mechanism of cross coupling presented in Chapter 19, and the reader might find it helpful to refer to the discussion of mechanisms of cross coupling in that chapter. Scheme 17.29 outlines the pathways for the carbonylation of aryl halides to form esters and amides. [Pg.797]

Before discussing the double carbonylation processes it may be helpful to understand the mechanism of the single carbonylation of aryl halides into carboxylic acid derivatives (Heck processes). The first step in the catalytic process is oxidative addition of an aryl halide to Pd(0) species formed from a catalyst precursor to yield an arylpal-ladium halide intermediate (A) in Scheme 1. Insertion of carbon monoxide into the aryl-palladium bond in A gives an acylpalladium halide complex (B). Attack of a nucleophile such as alcohol, amine, and water assisted by a base on the acylpalladium complex yields carboxylic ester, amide, and carboxylic acid, although details of the mechanism have not been unequivocally established. The palladium(O) species regenerated in the process further undergoes oxidative addition to carry out the catalytic cycle (Scheme 1). [Pg.748]

If the acylpalladium species can undergo further CO insertion to give a-ketoacylpalla-dium species and the complex should be attacked by a nucleophile, the double carbonylation process might be realized. However, the CO insertion into the acyl-transition metal bond seems to be a thermodynamically unfavorable process and the double CO insertion process is considered not operative for Pd-catalyzed double carbonylation of aryl halides. ... [Pg.748]

The carbonylation of aryl halides in the presence of suitable nucleophiles such as alcohols and amines offers an attractive approach to benzoic acid derivatives. Hence, the reaction of polymer-supported primary and secondary alcohols with aryl iodides under a carbon monoxide atmosphere was investigated. Under the reported reaction conditions, this three-component reaction proceeded in good yields and after cleavage the products were obtained in moderate to good purities (Scheme 27). ... [Pg.1433]

Nickel. Cinnamoylation of alkenes can be performed by allowing them to react with /ra/i -j8-bromostyrene and nickel carbonyl. Nickel-carbonyl-catalysed carbonylation of aryl halides is thought to have the following reactions as initial stages ... [Pg.319]


See other pages where And carbonylation of aryl halides is mentioned: [Pg.14]    [Pg.14]    [Pg.222]    [Pg.232]    [Pg.212]    [Pg.591]    [Pg.426]    [Pg.797]    [Pg.1006]    [Pg.73]    [Pg.74]    [Pg.200]    [Pg.234]    [Pg.281]    [Pg.189]   
See also in sourсe #XX -- [ Pg.910 ]




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And carbonylation of aryl

Aryl carbonylation

Aryl halides carbonylation

Aryl halides carbonylations

Arylation of aryl halides

Carbonyl halides

Carbonylation of aryl halides

Carbonylation of halides

Cobalt, octacarbonyldicatalyst carbonylation of aryl and vinyl halides

Halides carbonylation

Halides, aryl, arylation carbonylation

Palladium-Catalyzed Carbonylation of Aryl and Vinylic Halides

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