Organoaluminiums reactions with

Organoaluminium derivatives with the formuia RxAIZ3 x (Z = OR, OH, X) give rise to explosive reactions with methanol and ethanol. With very strong bases, the reaction can be written down as ... 

In addition, Wipf and co-workers104 have used silver(i)-catalyzed addition of zirconocenes to 3,4,6-tri-O-benzyl-D-glucal epoxide 93 for the stereoselective synthesis of a-C-glucosyl compounds 95 and 96 following a similar mechanism as in the reaction with organoaluminium and organoboron reagents (Scheme 32). 

The nucleophilic displacement of the acetoxy group of 4-acetoxy-l,3-dioxanes was also effected by metalated alkynes. Organoaluminium and organotin compounds have been employed <1998TL3103>. The stereochemical outcome is similar to that of the analogous reaction with a high preference for the 7 //-product (Equation 45). 

The precipitated brown / -TiCl3 undergoes, in certain spots of its surface, an alkylation reaction with the organoaluminium compound present in the reaction system, which results in the formation of active species with a Ti-C bond (or with a Ti-H bond in the case of a metal hydride activator (in these spots, scheme (8) shows the activation of a catalyst precursor such as TiCl3 with AIR3 as the catalyst activator ... 

Amides differ from carboxylic acids and other acid derivatives in their reaction with Li A1H4 Instead of forming primary alcohols, amides are reduced to amines (Fig.P). The mechanism (Fig.Q) involves addition of the hydride ion to form an intermediate that is converted to an organoaluminium intermediate. The difference in this mechanism is the intervention of the nitrogen s lone pair of electrons. These are fed into the electrophilic centre to eliminate the oxygen that is then followed by the second hydride addition. 

When using, however, two-component catalysts alcohols also react with inactive metal-polymer (aluminium-polymer) bonds which are formed in the chain transfer reactions with a cocatalyst. It is expedient to use the alcohol method only for catalytic systems and polymerization conditions for which the number of inactive metal-polymer bonds is low. Such a case is the polymerization of 4-methyl-1-pentene on vanadium trichloride activated with various organoaluminium compounds. For this system the influence of catalyst composition and polymerization conditions on Cp and kp was determined by quenching the polymerization with tritiated alcohol. 

The propagation reaction is the main step of catalytic polymerization. The study of its mechanism implies the elucidation of its elementary steps including the determination of the rate-determining step. The most important properties of AC, necessary for the reaction to proceed include i) the presence of a metal-carbon bond ii) coordinative unsaturation of a metal ion in the AC. Here, we discuss the data on the mechanism of the propagation reaction with respects to the AC containing the transition metal-carbon bond and also for organoaluminium compounds, i.e. when the AC contains a non-transition metal carbon bond. 

S. Pasynkiewicz Reactions of organoaluminium compounds with electron donors, pp. 509-521 (29). 

OAlMea > 0P(0R)2 > OSiRs alkenyl aluminiums, prepared for example by the carboalumination of acetylenes," participate in this reaction with retention of stereochemistry to give 1,4-dienes." Aryl phosphates are found to have a reactivity similar to that of aryl chlorides in their reaction with organoaluminium reagents, and have been used to prepare alkyl, alkenyl, and aryl benzenes in a nickel-catalysed reaction." ... 

As a follow-up of the aforementioned studies, Hoveyda and co-workers then addressed one of the limitations in scope their method still had. Indeed, more sterically demanding Si-containing aryl vinyl aluminiums were incompatible with the reaction conditions. Hence, they turned their attention to alternative methods for the preparation of organoaluminiums compatible with the asymmetric allylic substitution of allylic phosphates for the formation of quaternary stereogenic centres. Firstly, they studied the enantioselective substitution of alkyl vinyl aluminiums obtained from the hydroalumination with DIBAL-H of alkyl-substimted alkynes (Scheme 35) [65]. When the proper catalyst is chosen (Lll as chiral ligand), this... 

M. Boleslawski, Reactions of organoaluminium compounds with lead compounds and chemistry of the resulting aluminoxane side products. Chem. Abs., 1978, 89, 129 696. 

F. Sato, H. Kodama, and M. Sato. Coupling reaction of organoaluminium compounds with allylic halides catalysed by copper compounds. J. OrganometalHc Chem., 1978, 157, C30. 

V. P. Yurev, F. G. Yusupova, G. A. Gailyunas, and G. A. Tolstikov. Reactions of higher organoaluminium compounds with acetylene. Zhur. obshchei Khim., 1977, 47, 2045. 

Boleslawski, M. (Scientific Proceedings of Warsaw Polytechnic Institute, Chemistry, No. 18 Reactions of Organoaluminium Compounds with Lead Compounds and Chemistry of the Resulting Aluminoxane Side Products, Wydawnictwa Politechniki Warszaws-kiej, Warsaw, Pol., 1977, pp. 1/124 C.A. 89 [1978] No. 129696). 

Aluminium. There are two important routes to organoaluminium compounds, both starting from aluminium metal. These are reactions with halides RX, and with hydrogen and olefins. 

H. Yamamoto and H. Nozaki, Selective Reactions with Organoaluminium Compounds , Angew. Chem. Internat. Edn., 1978,17, 169. 

It is interesting to note that the reaction of Etl with Al metal to give the sesqui-iodide Et3Al2l3 wa.s the first recorded preparation of an organoaluminium compound (W. Hallwachs and A. Schafarik, 1859). 

As in the case of organoaluminium compounds, unusual stereochemistries can be imposed by suitable design of ligands. Thus, reaction of GaCh with 3,3, 3"-nitrilotris(propylmagnesium... 

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