Carbon-aluminum bonds reactions with

Alkylaluminum hydrides react with metal hydrides to eliminate RH, and if the metal fragment is bonded to a cyclopentadienyl ring, H2 may also be eliminated to produce a new aluminum-carbon bond, as illustrated in Equations (54)—(57).11,84,83 The hydride-bridged Al-Mo bond in 52 is considerably longer than the direct Al-Mo interaction (294.4(2) vs. 263.6(2) pm).83 A similar reaction with (C5H4R)Co(G2H4)2 yields a mixture of 5382... 

Because of the large excess of ethylene present in the growth reactor, the reverse reaction is insignificant. Ethylene reacts with dialkyl aluminum hydride much more rapidly than does the terminal olefin, and any alkyl group thermally displaced is replaced by an ethyl group. However, terminal olefin present in the growth reactor can react with trialkylaluminum compounds. The a-olefin inserts between the aluminum-carbon bond just as ethylene does in a normal growth process. 

Aluminum alkyls in reactions with carbon-carbon multiple bonds, oxiranes,... 

Carbocations are perhaps the most important electrophiles capable of substituting onto aromatic rings, because this substitution forms a new carbon-carbon bond. Reactions of carbocations with aromatic compounds were first studied in 1877 by the French alkaloid chemist Charles Friedel and his American partner, James Crafts. In the presence of Lewis acid catalysts such as aluminum chloride (A1C13) or ferric chloride (FeCl3), alkyl halides were found to alkylate benzene to give alkylbenzenes. This useful reaction is called the Friedel-Crafts alkylation. 

The complex Al(TPP)Et is unreactive to carbon dioxide in the dark. However, it is activated by visible light and carbon dioxide is inserted into the aluminum carbon bond in the presence of l-methyiimidazoIe Inoue demonstrated the formation of Al(TPP)C02Et by in situ infrared measurements and by characterization of the reaction products which are obtained by treatment of the reaction mixture with hydrogen chloride gas followed by 1-butanol or diazomethane (Eq. 17). 

Only one bimetallic mechanism is presented here, as an example, the one originally proposed by Natta. He felt that chemisorptions of the organometallic compounds to transition metal halides take place during the reactions. Partially reduced forms of the di- and tri-chlorides of strongly electropositive metals with a small ionic radius (aluminum, beryllium, or magnesium) facilitate this. These chemisorptions result in formations of electron-deficient complexes between the two metals. Such complexes contain alkyl bridges similar to those present in dimeric aluminum and beryllium alkyls. The polymeric growth takes place from the aluminum-carbon bond of the bimetallic electron-deficient complexes . ... 

The use of activated anthranihc acid derivatives facUitates the preparation of the amides in those cases where the amines are either umeactive or difficult to obtain. Thus, reaction of (87-1) with phosgene gives the reactive the isatoic anhydride (89-1). Condensation of that with ortho-toluidine leads to the acylation product (89-2) formed with a simultaneous loss of carbon dioxide. This is then converted to the quinazolone (89-3) by heating with acetic anhydride. Reaction with sodium borohydride in the presence of aluminum chloride selectively reduces the double bond to yield the diuretic agent metolazone (89-4) [99]. 

The reduction of tosylhydrazones can also be performed with sodium borodeuteride in boiling methanol or dioxane, but the mechanism of this reaction (in boiling dioxane at least) is radically different from that of the lithium aluminum deuteride reductions.82 With sodium borohydride the first step is apparently hydride attack on the carbon atom of the C=N bond which is probably concerted with the elimination of the tosylate anion (110 - 111). Migration of the hydrogen from nitrogen to C-3 in (111) concerted with expulsion of nitrogen, provides the corresponding methylene derivative (100).82... 

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