Magnesiums organoaluminums

EPOXIDES Alumina. r-Butyldimethyl-iodosilane. n-Butyllithium-Magnesium bromide. Cyclohexylisopropylamino-magnesium bromide. Dialkylaluminum amides. lodotrimethylsilane. Lithium l-a,a -dimethyldibenzylamide. Nafion-H. Organoaluminum compounds. Pyri-dinium chloride. Raney nickel. Tti-fluoroacetyl chloride, lrimethylsilyl-acctonitrile. Tris(phenylscleno)borane. Zinc iodide. 

Solution grafting has been the predominant approach for the immobilization of rare-earth metal precatalyst components [288]. The identification of the catalytically active surface species, commonly formed upon interaction with organoaluminum compounds, is difficult and assisted by molecular model complexes. Several types of support materials including magnesium chloride [289], silica [290], and organic (co-)polymers [291,292], were examined both in the gas-phase and the slurry polymerization of 1,3-dienes. 

The nucleophilic addition of organoaluminum reagent 60 to the magnesium salt 57 provided the homopropargylic cyclopropanol 61 in 50% yield. ... 

In order to prepare organoaluminum compounds with specific functional groups in the alkyl radical, reactions of aluminum halides with various metallic compounds are particularly important. Thus, vinyl magnesium halides and aluminum trichloride give unstable trivinylalane (see Section III,B,2) (17, 288) ... 

The reactivity of the aluminum-carbon bonds is greatly reduced in the 1 1 adducts, and this may be utilized in preparing particularly labile organoaluminum compounds which cannot be isolated in the free form. Thus tri-tert-alkyl alanes, such as tri-terf-butylalane, may be prepared as etherates from tertiary butyl lithium in diethylether (207) or from the corresponding magnesium tertiary alkyls (157, 159) ... 

Organoaluminum sonochemistry is not yet well developed despite the synthetic and economic interest. Aluminum, a ductile metal, is easily activated by sonication, as evidenced by the use of foils to determine the energy of cleaning baths. Alkyl halides react with aluminum at room temperature in THF to give the sesquihalide, reduced to the trialkyl compound in the presence of magnesium. Examples are known with bromomethane or -ethane.1 2,183 reaction occurs with stirring under similar conditions. Triethylaluminum was used in sonochemical transmetallation reactions leading to zinc and boron alkyls (Eq. 38). 

The Reformatskii reaction can be carried out conveniently with magnesium. If tert-huiy esters are used, the products can subsequently be transformed into satd. acids in a single operation Another easy method for the conversion of aldehydes to nitriles is their treatment with lead tetraacetate and ammonia in benzene Hydrocyanations can be efficiently performed with the help of organoaluminum compounds In this manner, steroidal cyanohydrins can be obtained from the respective epoxides by diaxial fission under mild conditions in high yield A number of addition reactions of nitrile oxides have been reported contrary to earlier reports, ar. nitrile oxides easily add hydrogen halides. 

Currently, the most efficient catalysts in terms of activity and enantioselectivity are binaphthol- and salen-based systems. The former is exemplified by a combination of BINOL and magnesium iodide, which catalyzes the conversion of prochiral ketones into enantiomerically enriched lactones with up to 65% ee [346]. When BINOL derivatives are combined with organoaluminum reagents, enantioselectivities of up to... 

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