Synthesis aluminum halides

The behavior of such activated halides as alkylating agents under Friedel-Crafts conditions expands the scope of the synthesis. Aluminum chloride enhances the electrophilic character of the a,/S-unsaturated carbonyl system and permits the nucleophilic attachment of the aromatic addendum (Y ) to the carbon bearing the positive charge, with displacement of halogen [Eq. (5)]. Thus,... 

The diazaphosphane or aminoiminophosphane ligands with a NPN framework are another subclass of cyclophosphazenes. These compounds with both phosphorus in oxidation state (111) [104-110] and (V) [111-112] have been employed in the synthesis of four membered heterocycles and coordination chemistry with group 13 derivatives. Several complexes of trivalent phosphorus derivatives with both aluminum halide and alkyls are known as illustrated for 48 in Scheme 21 [113-119]. The structure determination of 48 confirms the formation of a four membered metallacycle [116, 117],... 

But first the synthesis had to come John was interested in reduced metal halides, particularly for the post-transition metals cadmium, galHum, and bismuth (his Ph.D. dissertation was on anhydrous aluminum halides and mixed halide intermediates, a good start for what was to come ). However, he was not yet actively interested in rare-earth metals and their remarkable solubility in their halides. But these elements lured him one floor below where Adrian Daane headed the metallurgy section of Spedding s empire. He knew how to produce rare-earth metals with high purity and in sufficient quantity and also how to handle tantalum containers. What if one gave it a tr/ and reduced some rare-earth metal halides (John insists that this term is used correctly) from their respective metals at high temperatures under appropriate conditions. 

Hogeveen and co-workers <82JOC1909 83JOC4275> also reported the synthesis of tricyclic sulfinamides by the reaction of cyclobutadiene aluminum halide o complexes (65 or 66) with 53 at low temperature. Treatment of 65 or 66 with 53 at -60 °C resulted in the formation of 67 or 68 in 52% and 55% yields, respectively (Scheme 18). 

A large family of ionic liquids may be derived from the aluminum-containing species such as aluminum halides, especially aluminum chlorides. It seems appropriate to briefly examine the patent literature for a description of the synthesis of some members of this family of ILs. 

The synthesis ofhaloaluminate-based ionic liquids from halide salts and aluminum Lewis acids (most commonly AIX3 X=C1, Br) can generally be split into two steps (i) fomation of the desired cation by the reaction of a trialkylamine, trialkylphosphine or dialkylsulfide with a haloalkane, and (ii) formation of the haloaluminate anion by addition of an appropriate aluminum halide to this salt (Scheme 2.1). 

The use of an acyl chloride in the presence of aluminum chloride constitutes the most frequently used type of Friedel-Crafts ketone synthesis. Many examples from the earlier literature are reported in the reviews mentioned at the beginning of this chapter.The reactivity of acyl halides in reactions of acyl halides with aluminum halides decreases in the order I > Br > Cl > F, but a different order was report for reactions catalyzed by boron halides. In the latter case the order was acyl fluoride > acyl bromide > acyl chloride. We shall concentrate our attention on recently reported examples. 

Due u> possibility of hydrt>lysis of the halides w ith moisture and relatively slow reactions, synthesis is conducted in an inert atmosphere at elevated temperature (60-1 KfX ). AI-O-AI bonds arc established through decay of the interinediate complex, obtained by reacting aluminum alkoxide and aluminum halide. There are two possible pathways for this reaction a) nucleophilic attack of X on the electrophilic aluminum atom and b) nucleophilic attack of... 

We note that while tin reagents have often been employed for the organoboron halides/ the use of organostannanes as starting materials can also be applied to the synthesis of heavier group 13 derivatives. In the context of polyfunc-tional Lewis acid chemistry, this type of reaction has been employed for the preparation of ort/ o-phenylene aluminum derivatives. Thus, the reaction of 1,2-bis(trimethylstannyl)benzene 7 with dimethylaluminum chloride, methylaluminum dichloride or aluminum trichloride affords l,2-bis(dimethylaluminum)phenylene 37, l,2-bis(chloro(methyl)aluminum)phenylene 38 and 1,2-bis(dichloroalumi-num)phenylene 39, respectively (Scheme 16). Unfortunately, these compounds could not be crystallized and their identities have been inferred from NMR data only. In the case of 39, the aluminum derivative could not be separated from trimethyltin chloride with which it reportedly forms a polymeric ion pair consisting of trimethylstannyl cations and bis(trichloroaluminate) anions 40. 

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