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Aryllead triacetate, arylation

Arylation of nitroalkanes. An aryllead triacetate arylates nitroalkanes and the nitronate salts at the a-position in DMSO in 60-75% yield.5... [Pg.21]

A limited range of inorganic nucleophiles has been found to react with aryllead triacetates. Aryl iodides are easily produced by the reaction of aryllead triacetates with aqueous potassium iodide. [Pg.231]

The procedure described here serves to illustrate a new, general method for effecting the < -arylation of g-dicarbonyl compounds by means of an aryllead triacetate under very mild conditions. Although the first synthesis of an aryllead triacetate was reported relatively recently, a wide range of these compounds can now be readily prepared. The most direct route to these compounds is plumbation of an aromatic compound with lead tetraacetate, and in the procedure reported here p-methoxyphenyllead triacetate has been prepared in this way. It may also be obtained by reaction of the diarylmercury with lead tetraacetate, a longer, but more general method of synthesis of aryllead triacetates. [Pg.27]

Aryl iodides and fluorides can be prepared from arylthallium bis(trifluor-oacetates) (see 12-21), indirectly achieving the conversions ArH —> Arl and ArH ArF. The bis(trifluoroacetates) react with KI to give Arl in high yields. Aryllead triacetates, ArPb(OAc)3, can be converted to aryl fluorides by treatment with BFs-etherate. ... [Pg.799]

Aryllead triacetates are also good reagents for arylation of stabilized carbanions, including... [Pg.149]

The electrochemical reduction of aryllead triacetates was smdied by Chobert and Devaud82, as a re-examination of some previous work83 to detect the role of intermediates such as [ArPb(OAc)2]V The reductions were carried out by polarography in acetic acid or acidic alcohol solutions and show three diffusion controlled waves. The first step involves a single electron transfer to produce a radical anion which dimerizes, arylates the electrode or hydrolyzes to phenol ... [Pg.679]

The reactions of the 5-oxazolanes 14 with aryllead triacetates are examples of the typical arylation of heterocycles by which products 15 are formed. After hydrolysis and decarboxylation, heterocyclic compounds 15 are converted to the arylglycines 16 in yields of 81-93% (Equation (5)).33... [Pg.887]

Only a few more recent examples of the numerous studies on N-arylations with aryllead triacetates will be discussed here. For earlier publications in this field, the interested reader is referred to the pioneering arylations of aliphatic and aromatic amines by Barton s group, 8 as well as the comprehensive review article by Elliott and... [Pg.888]

Imines, sulfonamides, and hydantoins undergo copper-catalyzed arylation by aryllead triacetates in the same manner. In many cases, prior conversion of the N-H bonds into the corresponding sodium salts is recommended.43 44... [Pg.888]

Aryllead triacetates a-arylate ketones highly selectively, working well for tertiary a-carbons, or secondary ones activated by a phenyl group,146 thus favouring arylation of positions that are typically already crowded, making the reaction very useful synthetically. [Pg.25]

Arylalkanoic acids, 109 Arylanthranilamides, 367 4-Arylbutanoic acids, 321 Aryl diazoalkanes. 565 Aryldiazonium chlorides. 495 Aryllead triacetates, 31-32... [Pg.331]

Aryllead triacetates, ArPb(OCOCH3)3. These reagents can be obtained by reaction of an aryl compound with lead tetraacetate in dichloroacetic acid or trichloroacetic acid (the reaction is slow in acetic acid).1 Another general route is reaction of a iliaiyltnercury with lead tetraacetate.2,3... [Pg.358]

Amine arylation.1 This reaction can be effected at 25° with aryllead triacetates in the presence of Cu(OAc)2. Yields are high in reactions of anilines substituted by electron-releasing groups. Only primary linear aliphatic amines are arylated, albeit in poor yield. [Pg.16]

N-Arylation of various azoles (or their anions) was readily accomplished with p-tolyllead triacetate in the presence of copper(II)acetate [95JOC5678] however, die applicability of this procedure to other aryllead triacetates was not discussed. Solvent-dependent palladium-mediated allylations [95JHC1325] and Mitsunobu-based asymmetric alkylations [95JOC2008] of imidazoles and benzimidazoles have also been reported. [Pg.151]

Mixed arylation of bifunctional substrates, such as those containing two /3-ketoester groups in their structure can be made. This possibility was used to synthesize unsymmetrically substituted compounds containing two different aryl groups (Scheme 2). One-pot treatment of the dibenzyl 3,7-dioxobicyclo [3.3.0]-octane-2,6-dicarboxylate 6 with a mixture of two aryllead triacetates 7 and 8 afforded a mixture of the unsymmetrical diaryl derivative 10 with the two symmetrical diaryl compounds 9 and 11. When the arylation was performed with 1.1 equiv. of each aryllead reagents 7 and 8, a mixture of 9-11 in a ratio 0.46 1 0.72 was obtained. This ratio became 0.43 1 0.49, when 0.86 equiv. of 7 and 1.33 equiv. of 8 were used. This compound 10, isolated in a 33% yield, was eventually elaborated to complete a total synthesis of ( ) methyl piperitol.25... [Pg.384]

The nature of the acyl ligand of the aryllead triacetate has no influence on the diastereomeric ratio (Equation (19)). It is interesting to note that, when the sodium salt of the /3-ketoesters was treated with p-MeOC6H4Pb(OCOR)3 at 25 °G, the arylated product was obtained in 60% yield with a 9 1 diastereomeric ratio.49... [Pg.390]

The reaction of 4-(methoxycarbonyl)chroman-3-one with aryllead triacetates afforded the expected 4-aryl derivatives 28 in moderate to good yields (see Section 9.09.2.1, Equation (6)). However, with longer reaction times the products of bis-arylation 29 were obtained in moderate yields (Equation (35)). Unsymmetrically disubstituted chro-man-3-ones were obtained by treatment of the pure product of monoarylation, the 4-monosubstituted compound, with a second aryllead triacetate (Equation (36)). [Pg.394]

In their early studies, Pinhey et al. showed that, when the reaction of a phenol with an aryllead triacetate is performed in the presence of pyridine, only the C-arylated dienones 35 and 36 are formed in a nearly quantitative yield (90% ortho para ratio of 4 1) (Equation (38)). Under their classical conditions (phenol organolead triacetate base in a ratio 1 1 3), the reaction of methylated phenols only proceeded in high yield when both ortho-positions are substituted. There is a preference for attack ipso to a methoxyl group compared to a methyl group.45 453... [Pg.395]

In general, the rate of the reaction of arylation of phenols by aryllead triacetate increases with the electron density of the phenolic substrate. When pyridine is used as a base, no reaction takes place with electron-poor phenols, such as 2,6-dichlorophenol or 2,6-dichloro-4-nitrophenol.45 45a However, the reaction of the sodium salt of perfluorophenol 43 with phenyllead triacetate under more forcing conditions led to a range of products the product of >rtfe -arylation, the 6-aryl-2,4-cyclohexadienone 44 together with minor amounts of the product of / zra-arylation 45 and the unsymmetrical diaryl ether 46 (Equation (43)).69... [Pg.397]

Thus, in the reaction of aryllead triacetate with phenols, an initial ligand exchange affords an aryl-(aryloxy)lead diacetate intermediate which can have the aryloxy ligand either in the axial position 51 or in the equatorial position 52 (Scheme 9). If the aryloxy group is in the axial position, pseudorotation can easily interconvert this conformer with... [Pg.398]

The reaction of A-alkylaniline derivatives with aryllead triacetates led to the trisubstituted WalksT/V./V-diaryla-mine in modest yields. For example, arylation of 5-aminoindane (73, R = H) with />-tolyllead triacetate 58 gave the... [Pg.406]

Copper diacetate-catalyzed arylation of heterocyclic amines such as piperidine, tetrahydroisoquinoline 76101 or 1,6-diazacyclodecane 77104 by aryllead triacetates gave only modest to moderately good yields of the iV-aryl derivatives (Equation (76) and (77)). The reactions with aliphatic amines lead to particularly poor yields of the derived anilines101 (Equations (78) and (79)), although the arylation of cyclooctylamine 78 with an electron-rich aryllead triacetate afforded the aniline derivative 79 in a moderately good yield (52%) (Equation (80)).1O5 1O5a... [Pg.407]

O-Arylation of alcohols or phenols cannot be performed by copper diacetate-catalyzed reactions using aryllead triacetates as the source of the aryl ligand. However, Dodonov et at. reported that tetraphenyllead reacts with primary and secondary alcohols in the presence of copper diacetate to afford the derived O-phenyl ethers in moderate yields ranging from 1.25 to 1.8 mol. of ether per mole of the lead reagent (Equation (100)). Phenol and tert-butyl alcohol afforded lower yields of the ethers (0.72-0.95 mole per mole of the lead reagent).117... [Pg.411]

Although H NMR spectra of aryllead triacetates can be recorded in CDCI3 solution in the presence of tetra-methylsilane, cleavage of the methyl-silicon bond takes place when tetramethylsilane is treated with an aryllead(rv) tricarboxylate in trifluoroacetic acid.164 When the aryl moiety is substituted with an electron-withdrawing group, quantitative conversion of TMS was observed to give aryl(methyl)lead dicarboxylates 111, (Equation (136)) that were even isolated in two instances, although in modest to moderate yields 55% yield for the 4-fluorophenyl compound and 23% yield for the 4-trifluoroacetamidophenyl compound. [Pg.421]

The procedure described here serves to illustrate a new, general method for effecting the -arylation of g-dicarbonyl compounds by means of an aryllead triacetate under very mild conditions. Although the first synthesis of an aryllead triacetate was reported relatively recently, a wide range of... [Pg.131]

A particular use of aryllead triacetate is reported74 by which cycloalkanone enamines are arylated at the /f-carbon atom, giving sometimes acetoxylated compounds as by-products, by a mechanism analogous to that proposed for thallium triacetate75. [Pg.947]

The value of 4-hydroxycoumarin in synthesis has been discussed <07THC(11)283> and its use in the synthesis of 3,4-disubstituted coumarins has been reported <07JOC7279>. The 3-arylation of 4-hydroxycoumarins, achieved using aryllead triacetates, sets up a substrate for a cascade of reactions which leads to the [2]benzopyrano[4,3-c][l]benzopyran system <07JOC3293> and the EDDA-catalysed reaction of 4-hydroxycoumarin with a,[3-unsaturated arylaldehydes produces pyrano[3,2-c]benzopyran-5-ones <07T10025>. Propargylation and... [Pg.415]

The a-arylation of ketones, such as cyclohexanone, can be achieved using different methods. A convenient route by Pinhey et al.89), reacts cyclohexanone-2-carboxylic esters with aryllead triacetates in pyridine. The protection of the P-carboxylic ester prevents a,a-di- or even higher arylations in a -positions. The ester group can be removed by basic hydrolysis and mild thermal decarboxylation or by heating in wet dimethylsulfoxide with sodium chloride (120-180 °C)90). Barton et al. 91) have found a similar a-arylation route using the less electrophilic triphenylbismuth carbonate. In both cases probably the lead- or bismuth-enolates, respectively, are the first inter-... [Pg.111]


See other pages where Aryllead triacetate, arylation is mentioned: [Pg.446]    [Pg.584]    [Pg.615]    [Pg.646]    [Pg.283]    [Pg.382]    [Pg.382]    [Pg.383]    [Pg.385]    [Pg.386]    [Pg.393]    [Pg.394]    [Pg.399]    [Pg.406]    [Pg.407]    [Pg.411]    [Pg.203]    [Pg.884]   


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