Aromatic compounds arylated

Arylamines are converted by diazotization with nitrous acid into arenediazonium salts, ArN2+ X-. The diazonio group can then be replaced by many other substituents in the Sandmeyer reaction to give a wide variety of substituted aromatic compounds. Aryl chlorides, bromides, iodides, and nitriles can be prepared from arenediazonium salts, as can arenes and phenols. In addition to their reactivity toward substitution reactions, diazonium salts undergo coupling with phenols and arylamines to give brightly colored azo dyes. 

The main types of substrates investigated so far are polycyclic aromatic compounds, aryl substituted carbo- and heterocyclic pentadienes, cyclic 1,3-dienes, furans, and olefins. It has turned out that type II photooxygenation of these compounds in solution occurs via the oxygen-activation mechanism. 

Photochemical Arylation of Aromatic Compounds Arylation or Aryl-de-hydrogenation... 

MORE ON AROMATIC COMPOUNDS. ARYL OXYGEN COMPOUNDS SIDE-CHAIN DERIVATIVES... 

More on Aromatic Compounds. Aryl Oxygen Compounds Side-Chain Derivatives... 

Aryl tellurium trichlorides and tribromides condense with methoxybenzene4,5, 1,3-dihydroxybenzene, and dimethylaniline6 to give unsymmetrical diaryl tellurium dihalides. The condensations occur with the hydrogen atom in the para-position to the activating group in the aromatic compound. Aryl tellurium triiodides did not react6. 

The system consisting of gaseous BFs/EtsSiH has been reported "- to reduce aldehydes and ketones thus benzaldehyde was reduced to toluene in 52% yield. In alkyl carbonyl compounds, aldehydes afford the corresponding alcohol products, whereas ketones, such as undecan-2-one and cyclohexanone, are readily converted to the hydrocarbons in high yields. On reduction with limited amounts of both reagents these alkyl ketones were reduced to the alcohols, indicating the intermediacy of the corresponding borate ester. In the case of aromatic compounds, aryl aldehydes and diaryl and alkyl aryl ketones are reduced to... 

The mechanism of thallation appears to be complex, with electrophilic and electron-transfer mechanisms both taking place. Transient metalated aryl complexes can be formed that react with another aromatic compound. Aryl iodides reacted with benzene to form a biaryl in the presence of an iridium catalyst. Aniline derivatives reacted with TiCLj to give the para-homo coupling product (RaN-Ar-Ar-NRj). ... 

While the electrografting mechanism is the same for carbon and metals, a different one has been proposed for semiconductors such as hydrogenated Si. In this case, once the aryl radical is formed close to the surface, it reacts with the substrate by homolytic cleavage of Si-H bond to give a stable aromatic compound (aryl-H) and leave a silyl radical (Si ) on the surface. This silyl radical then combines with another aryl radical in the vicinity of the electrode to form the expected Si-C chemical bond. 

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