Aluminium reagents

The AAA of allylphosphates by vinyl aluminium reagents generated in situ by hydroalumination of terminal aUcynes with DIBAL-H in situ has recently been reported (Scheme 2.24). 

When the chiral a,jS-enone enoate 98 was treated with magnesiocuprates in the presence of 1.5-2 equivalents of diethylaluminium chloride, the anti addition product 99 was obtained in moderate yield and with good diastereoselectivity (Scheme 6.21) [43, 44]. A reasonable explanation might assume a chelating coordination of the aluminium reagent [45]. Thus, if the enone 98 were to adopt an s-trans conformation, as indicated for complex 100, subsequent front side attack of the nucleophile would furnish the major diastereomer anti-99. 

Supported Ziegler-type neodymium surface species (54, see below) have been prepared by mixing molecular components composed of [Nd(naph)3] (derived from naphthenonic acids) and alkyl aluminium reagents such as Al2Et3Cl3, Al( Bu)3 and/or Al( Bu)2H at 50-60°C with silica (source QiLu Petrochemicals Co., China) [158-160]. Although the immobihzed neodymium species are iU-defined, the materials display interesting properties in butadiene polymerization (Section 12.4.1.2). 

H. Haubenstock, Asymmetric Reductions with Chiral Complex Aluminium Hydrides and Tricoordinate Aluminium Reagents, Top. Stereochem. 1983, 14, 213. 

Although alkylmagnesium, -zinc, -tin, and -aluminium reagents have been successfully used for the cross-coupling reaction with organic halides [1], the reaction of alkylborane... 

With a mixture of an aldehyde and a ketone (or with ketoaldehydes), organolithium or Grignard reagents may be induced to react with the aldehyde or keto function by judicious choice of aluminium reagent. Thus, the amphiphilic methylaluminium bis(2,6-di-/er/-butyl-4-methylphenoxide) (MAD) boosts the electrophilicity of the former, while dimethylaluminium N-methylanilide traps aldehyde groups in situ, thereby isolating the keto group to react with the nucleophile. 

With an increasing understanding of this heterogeneous reaction these investigations have also been extended to the formation reaction of organo-lithium, -zinc and -aluminium reagents. 

Vinyl aluminium reagents 2.128 prepared by the hydroalumination of propargylic alcohols 2.127 can also undergo coupling (Scheme 2.45). This chemistry has been employed on a multigramme scale for the... 

The same stereochemical result has been observed with silicon," boron" and aluminium reagents (Scheme 9.35)." The lactone 9.110 reacts with the vinyl aluminium reagent 9.109 to give the trans acid 9.111. 

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