Aryl metallation

Benzimidazole, 2-amino-5-bromo-l-methyl-diazo coupling, 5, 429 Benzimidazole, 2-amino-6-bromo-1 -methyl-diazo coupling, 5, 429 Benzimidazole, 2-amino-1-ethyl-alkylation, 5, 438 Benzimidazole, 2-amino-1-methyl-acylation, 5, 438 bromination, 5, 429 tautomerism, 5, 368 Benzimidazole, 4-amino-2-methyl-diazo coupling, 5, 429 Benzimidazole, 2-aroyl-mass spectra, 5, 360 Benzimidazole, 1-aryl-metallation, 5, 448 reactions... 

Diazo compounds Diazoniiim sulfides and derivatives, Xanthates 1,2-epoxides Halo-aryl metals Haloarenemetal TC-complexes Halogen oxides Hydraziniiim salts Hyjiohalites... 

Acetyl hypofluorite is very effective m the fluorination of the aryl-metal (Hg, Ge, or Si) bond, but yields are frequently low. With aryl silicon compounds some competition exists for replacement of an aromatic hydrogen [5i, 52, 55, 54] (equations 25-27). Fluoroxytrifluoromethane fluorinates p-methoxypheny 1 mercuric acetate to givep-fluoroanisole in 86% yield [52]... 

In analogous reactions arylmetal compounds of thallium (ArTICl, addition of Tl-Na alloy, Nesmeyanov and Makarova, 1952), of tin (Ar2SnCl2, addition of Sn, Nesmeyanov et al., 1936), of lead (Ar4Pb, Pb-Na alloy, Nesmeyanov and Makarova, 1954 Nesmeyanov et al., 1954) were obtained (yields up to 80% with Hg, 10-40% with the other metals). Tetravalent metal salts often react to give a mixture of partially arylated metal chlorides (ArwMCl4 , n = 1 to 3). Waters (1939) was one of the few chemists outside Nesmeyanov s school who worked on that subject (arylation of lead). 

The decrease in scientific activity on arylmercury and related arylated metal compounds is probably due to the lack of interest for technological purposes, and to the environmental problems which these compounds cause. 

To summarize the foregoing brief report on alkyl and aryl metal compounds, we can cite the following points. 

Both alkyl and aryl metals have been studied, but not a very wide range of compounds. Several studies of triphenylarsene and triphenylstibine have been done. Methyl and ethyl compounds of arsenic, germanium, mercury, bismuth, and lead essentially complete the list. In virtually all cases the results have been clouded by difficulties in effecting chemical separation without altering the product distribution. The results do, nonetheless, lead to valid and important conclusions. 

Dendritic Sphere Based on Aryl-Metal Complexes. 44... 

Brief consideration will be given to NMR investigation of intermediates, products and kinetics of reactions. Alkylation, arylation, metalation, reaction with organometallics, thermolysis and thermal rearrangements, isomerisation and many other reactions such as the Wittig, Michaelis and Arbuzov reactions, which are typical of organophosphorus... 

M.J. Adam, J.M. Berry, L.D. Hall, B.D. Pate, T. Ruth, The cleavage of aryl-metal bonds by elemental fluorine—Synthesis of aryl-fluorides. Can. J. Chem. 61 (1983) 658-660. 

Stereoselective synthesis of 1,4-dienes This Pd complex markedly catalyzes the cross-coupling of alkenyl and aryl metals containing Al, Zr, or Zn with allylic halides, but not of alkyl metals. The coupling is markedly stereo- and regioseleclive. Examples ... 

The use of metal alkyls, metal aryls, metal hydrides, and metal carbides for preparing alcoholates of carbohydrates in inert, aprotic solvents has not yet been reported. 

In Section II, the structures of alkyl and aryl metal amides of the metallic elements Mg, Ca, Sr, Ba, Al, Ga, In, and T1 are briefly discussed from a general point of view. Some analogous compounds of other elements are included for comparison. 

STRUCTURAL ASPECTS OF ALKYL AND ARYL METAL AMIDES... 

Reactive centers in a cyclic or chelated alkyl or aryl metal silizane, such as compounds 31-54, are (1) the polar metal-carbon bond, (2) the polar metal-nitrogen bond, and (3) other bonds in the silazane, especially nitrogen-hydrogen bonds. We have been interested in reaction centers (1) and (3) and have... 

The alkyl and aryl metal silazanes and poly(metal) silazanes described so far are representatives of an unusual class of compound containing simultaneously electron-deficient and electron-rich centers that can interact with one another. The interaction may be of the two-electron donor type (Lewis acid/... 

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