Aluminium trichloride adducts

The first examples of phosphirenium salts (129) have been prepared from the reactions of alkynes with the aluminium trichloride adducts of dichlorophos-phines. The reactions of phosphines with fluorotrihalogenomethanes lead to the first examples of fluorine-containing phosphoranium salts (130). The related nitrogen-bridged salt (131) is formed in the reactions of lithium bis(diphenyl-phosphino)amide with iodomethane. ... 

The donor-acceptor complex (2) is isolated from tetrachloromethane solution ( ]. = 2.2), the ionic salt (3) from chloroform solution (er = 4.9). When dissolved in chloroform, the donor-acceptor complex recrystallizes as the ionic salt. Similarly, the ionic salt is converted to the donor-acceptor complex when dissolved in tetrachloromethane. This result shows that in solution an equilibrium exists between the two forms. The isolation depends on the solvent used for recrystallization. Similar results have been obtained in the case of the adduct between acetyl chloride and aluminium trichloride, which is un-ionized in chloroform, but completely ionized in nitrobenzene [160],... 

The adduct formed between the alkyl halide and the aluminium trichloride may react further by fragmenting. Suggest how this may happen. 

The regio- and stereo.selective 2 + 2 cycloaddition of phenylacetylene to the allene 147 results in the (Z)-cyclohutenylideneoxazolidin-2-one 148 similarly, methyl acrylate affords the analogue 149 <97JA10869>. The dimetliyleneoxazolidinone 150 adds methyl vinyl ketone in the presence of aluminium trichloride or titanium tetrachloride to yield mainly the endo Diels-Alder adduct 151 <97JOC4103>. 

Treatment of the enone (69) with an excess of the diene (70) in the presence of aluminium trichloride and 4,4-thiobis-(6-t-butyl-3-methylphenol) gave the tricyclic ketone (71) (40%) as the sole Diels-Alder product. Reduction then afforded the lactone (72) whose constitution and stereochemistry were established by X-ray analysis. Finally, demethylation gave the racemic alcohol (73) which differs from the quassin skeleton only in the stereochemistry at C-9. The Diels-Alder reaction also plays a key role in two other de novo syntheses. The ring A seco-derivative (75) has been prepared from the adduct (74), and the ring A nor-compound (77), a possible intermediate for the synthesis of quassimarin (78), has been obtained from the Diels-Alder product (76). ... 

Treatment MBH adducts with aluminium trichloride (from the acetate), thionyl chloride,phosgene and A-chlorosuccinimide (NCS)/dimethyl sulflde, respectively, furnishes chlorides 65 and 66. With thionyl chloride in the presence of pyridine, the MBH adduct gives predominantly the unrearranged chloride 66. Equimolar mixtures of rearranged and unrearranged chlorides were obtained from ethyl 2-(l-hydroxyethyl)acrylate and ethyl 2-(l-hydroxybutyl)acrylate with hexachloroacetone/triphenylphosphine, while... 

A synthesis of a compactin fragment utilized the bicyclic adduct (76) obtained by aluminium trichloride-catalysed addition of butadiene to the corresponding glycosenone... 

The mechanism of the formation of the complex, 5.1, is not known. The possibility of an adduct between AIQs and the neutral (jr-C H )2Cr has been ruled out [24]. It has, however, been shown that the product of the reaction between bis-Ti-benzene chromium and AICI3 is the complex 3[(2i-C6H6)2Cr]+AlCl4 ,4AlCl3, and it seems probable that this complex is also formed as an intermediate in the preparation [23]. Indeed, bis-7r-arene chromium complexes will equilibrate with free arene ligands in the presence of aluminium trichloride [25a],... 

It forms an ion BCI4 only under special circumstances, and never in aqueous solutions (cf. BF3). Like the trifluoride, it is an electron pair acceptor, but the adducts formed tend to decompose more readily. Unlike the corresponding aluminium chloride, boron trichloride exists only as the monomer. 

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