Alkynes tris aluminum

Tris(dimethylamino)sulfonium difluo-rotrimethylsilicate, 336 Xenon(II) fluoride, 345 Alkyl bromides Potassium permanganate, 258 Sodium bromide, 46 Tetraethylammonium bromide, 46 Alkyl iodides Aluminum iodide, 17 Potassium permanganate, 258 Sodium iodide, 46 Tetraethylammonium iodide, 46 Alkynes (see also Acetylenic carbonyl compounds, Diynes, Enynes, Propar-gyl alcohols)... 

Treatment of lithium alkynides with aluminum trichloride leads to tri(ethynyl)aluminum intermediates, which on treatment with haloalkanes give the corresponding disubstituted acetylenes. " The reaction is successful with tertiary haloalkanes and a variety of alkynes have been prepared (Scheme 9). An interesting variation of this method has been reported by Trost and Ghadri who reacted a diethylethynylalumin-um with an allyl sulfone in the the presence of the Lewis acid aluminum trichloride. When the allyl sulfone was part of a six-membered ring, then the alkyne was introduced exclusively in a pseudo axial orientation (Scheme 10). 

If 1-alkynes are reacted with 2 moles of R2A1H or the dialkyl-l-alkenyl alanes with the addition of a further mole of dialkyl alane, compounds are obtained with two dialkyl aluminum groups on the terminal carbon atom. Likewise 1 mole of dialkylalkynyl alane and 2 moles of dialkyl alanes give tris(l,l,l-dialkylalanyl) alkanes. Deuterolysis of fully hydroaluminated propynylalane, for example, thus gives 1,1,1-trideuteropropane (219) ... 

There are several alternative methods for the formation of acylsilanes these include the reaction of silyl cuprates with acid halides, palladium-assisted coupling of acyl halides with hexamethyldisilane, the reaction of thiopyridyl esters with tris(trimethylsilyl)aluminum in the presence of Cu salts, and the hydroboration of trimethylsilyl-substituted alkynes. While all of these procedures are complementary, the method involving the title corqtound provides an easy, inexpensive route to acylsilanes. 

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