Organoaluminum compounds coupling

Organoaluminum compounds couple very well with tertiary (to give products containing a quaternary carbon) and benzylic halides at -78°C.1301 This reaction can also be applied to allylic, secondary, and some primary halides, but several days standing at room temperature is required (see also 0-90). Products containing a quaternary carbon can also be... 

Prepa.ra.tlon, There are several methods described in the Hterature using various cobalt catalysts to prepare syndiotactic polybutadiene (29—41). Many of these methods have been experimentally verified others, for example, soluble organoaluminum compounds with cobalt compounds, are difficult to reproduce (30). A cobalt compound coupled with triphenylphosphine aluminum alkyls water complex was reported byJapan Synthetic Rubber Co., Ltd. (fSR) to give a low melting point (T = 75-90° C), low crystallinity (20—30%) syndiotactic polybutadiene (32). This polymer is commercially available. 

Organoaluminum compounds undergo the coupling reaction with acyl chlorides in the presence of palladium catalyst Not only alkyl-, alkenyl-, and alkynylalanes bnt also alkenylalanates are used for the reaction. This reaction can also proceed in the absence of palladium catalyst, but the stereoselectivity is much better when the reaction is catalyzed by palladium (Scheme 11). ... 

The first carbonylative coupling of organoaluminum compounds appeared in 1985. Beletskaya and colleagues [88] demonstrated that ketones are produced in good yields by a palladium-catalyzed reaction of arylaluminium compounds with aryl iodides in the presence of CO (Scheme 4.49). That same year, the... 

Abstract The use of organoaluminum-based Lewis acids (A1R X3 R = alkyl, alkynyl, X = halide or pseudohalide) in the period 2000 to mid-2011 is overviewed with a focus on (1) stoichiometric reactions in which one of the organoaluminum substituents is transferred to the substrate (e.g., the opening of epoxides, 1,2-additions to carbonyl compounds, coupling with C-X, and Reissert chemistry) and (2) asymmetric, often catalytic, reactions promoted by Lewis acid catalysts derived from organoaluminum species (e.g., use of auxiliaries with alanes, Diels-Alder, and related cycloaddition reactions, additions to aldehydes and ketones, and skeletal rearrangement reactions). 

E. Cross-coupling Reactions of Organoaluminum or Organozirconium Compounds in the Presence of Nickel or Palladium Catalysts... 

Intramolecular A1C addition to the C=C double bond is also observed to a small extent (ca. 1%) in the hydroalumination of 1,6-heptadiene (88). Such C—C coupling hinders the synthesis of long-chain bifunctional compounds from low molecular dienes through organoaluminum intermediates. In contrast to this, 1,7-octadiene gives only the bis-hydroalumination products. With 1,7-octadiene (which may be prepared by pyrolysis of cyclo-octene) (226) as the starting material, a route is available to the long-chain bifunctional bis-hydroalumination products and their derivatives (see Section V,C,l,a). 

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