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Arenediazonium salts carbonylation

Aquaspirillum magnetotacticum magnetotactic, 680 Arco-Oxirane process, 327 Arenediazonium salts carbonylation, 290 Arenes... [Pg.7180]

Aldehydes and ketones are formed in reactions of arenediazonium salts with derivatives of carbonyl compounds, e.g., with oximes (Scheme 10-40, Jolad and Ra-jagopal, 1973) or with diacetyl (Scheme 10-41, Citterio et al., 1982b). In most cases yields are mediocre. Better results are obtained with CO, tetraalkyltin, and Pd(OAc)2 as catalyst (Kikukawa et al., 1987). [Pg.242]

Meerwein reactions can conveniently be used for syntheses of intermediates which can be cyclized to heterocyclic compounds, if an appropriate heteroatom substituent is present in the 2-position of the aniline derivative used for diazotization. For instance, Raucher and Koolpe (1983) described an elegant method for the synthesis of a variety of substituted indoles via the Meerwein arylation of vinyl acetate, vinyl bromide, or 2-acetoxy-l-alkenes with arenediazonium salts derived from 2-nitroani-line (Scheme 10-46). In the Meerwein reaction one obtains a mixture of the usual arylation/HCl-addition product (10.9) and the carbonyl compound 10.10, i. e., the product of hydrolysis of 10.9. For the subsequent reductive cyclization to the indole (10.11) the mixture of 10.9 and 10.10 can be treated with any of a variety of reducing agents, preferably Fe/HOAc. [Pg.245]

Barbituric acid can be considered as a cyclized malonic acid diamide (malonyl-urea). It is therefore a cyclic diketone that may be classified, in the sense of the compounds discussed in Section 12.6, as a coupling component with a methylene group activated by two carbonyl groups in the a- and a -positions. The reaction with arenediazonium salts was studied by Nesynov and Besprozvannaya (1971). These authors obtained coupling products (in good yield) that they considered to be arylhydrazones. Coupling with 4-(phenylazo)benzenediazonium chloride was studied by Chandra and Thosh (1991). The lH NMR spectra of these compounds are consistent with the arylhydrazone structure 12.68. [Pg.332]

Carbonylative cross-coupling of arenediazonium salts with arylboronic or styrylboronic acids was realized using a... [Pg.416]

Arenediazonium salts can be carbonylated to give mixed anhydrides in the presence of NaOAc and catalytic amounts of [Pd(OAc)2]. The mixed aryl-acetic anhydrides formed were generally hydrolyzed in situ and the free carboxylic acids were isolated. The carbonylation occurs according to equation (136).542... [Pg.290]

Other pseudohalides are carbonylated. Benzoic acid derivatives are prepared from arenediazonium salts at room temperature without addition of a phosphine ligand [223], For example, the acid anhydride 457 is prepared by the carbonylation of the benzenediazonium salt 456 in the presence of AcONa. By this method, nitrobenzene can be converted to benzoic acid indirectly. [Pg.87]

Arenediazonium salts react stoichiometrically with nickel and iron carbonyls to give aromatic carboxylic acids in moderate yield, but a more reliable procedure involves direct, catalytic carbonylation in the presence of palladium acetate. The reaction proceeds at room temperature under CO pressure (9 bar)... [Pg.1026]

Although indoles are less reactive than pyrroles, they react with arenediazonium salts to give 3-(aryl-azo)indoles. The reaction with carbonyl compounds proceeds in an analogous way in the presence of acids. For this reason, indoles unsubstituted in the 3-position give a positive colour test with Ehrlich s reagent. Indole and acetaldehyde react via an azafulvenium salt to give 3-Vinylindole, which on further reaction with indole forms l,l-di(indol-3-yl)ethane ... [Pg.100]

Trimethylsilyl)phenyldiazene (10.23) is an interesting alternative to arenediazonium salts, although the N(J3) — Si bond is clearly covalent. Abel and Burton (1979 see also earlier references there) used it to replace a carbonyl group in monobromo(pentacarbonyl)manganese (10-7). The trimethylsilyl part of 10.23 (as... [Pg.431]

Diazotization Synthesis of arenediazonium salts from benzenamines (anilines) using cold nitrous acid. t-Dicarbonyl compound A useful intermediate bearing two carbonyl groups adjacent to the same... [Pg.507]

Arenediazonium salts, irrespective of the electronic nature and the position of the substituents on the aromatic ring, undergo a smooth carbonylative cross-coupling reaction with tetramethylstannane in the presence of 2% of Pd(OAc)2 under 9 atm of CO at room temperature (Scheme 9). Tetraethylstannane is less reactive and aryl ethyl ketones are obtained in less than 50% yields. Tetrabutylstannane does not react under these conditions. The reaction is successful for X = BF4 and PFg, but not for X = Cl. In this case, the yields drop to less than 10% and intractable tarry material results (Scheme 9). ... [Pg.775]

Addition of tributylstannyl-lithium to crotonaldehyde and protection of the resulting alcohol with chloromethyl methyl ether gives the stannane (192), which reacts with both alkyl and aryl aldehydes RCHO to form specifically the t/rr o-hydroxy-enol ethers (193). These latter compounds have been used to prepare tra/i5-4,5-disubstituted butyrolactones by hydrolysis and subsequent oxidation. Palladium-catalysed carbonylation of RX in the presence of organotin species constitutes a useful synthesis of unsymmetrical ketones, and in the example reported this year RX is an arenediazonium salt. The reaction, which is basically an aromatic acylation, proceeds in good to excellent yield. Another Pd-catalysed reaction of aromatics, this time aryl bromides, is their reaction with acetonyltributyltin (194), prepared from methoxytributyltin and isopropenyl acetate, to give the arylacetones (195). ... [Pg.289]


See other pages where Arenediazonium salts carbonylation is mentioned: [Pg.78]    [Pg.73]    [Pg.172]    [Pg.412]    [Pg.138]    [Pg.414]    [Pg.149]    [Pg.172]    [Pg.102]    [Pg.327]   
See also in sourсe #XX -- [ Pg.290 ]

See also in sourсe #XX -- [ Pg.3 ]

See also in sourсe #XX -- [ Pg.290 ]

See also in sourсe #XX -- [ Pg.1026 ]

See also in sourсe #XX -- [ Pg.3 ]




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