Alkenes organoaluminum hydrides

For main group metals, which exhibit relatively small differences between M—H and M—C bond strengths and no strong metal-alkene interactions, the thermodynamics of hydrometallation should be even more favorable than for early transition metals. This does not appear to be the case, especially for hydroalumination (Volume 8, Chapter 3.11). The reason is almost certainly the additional stability of the metal hydride reagent conferred by aggregation organoaluminum hydrides exist as rather tight dimers. 

Since alkali aluminum hydrides with alkenes give alkali aluminum tetraalkyls (alkali tetraalkyl alanates) (291, 293), a further simple route to aliphatic organoaluminum compounds is opened up ... 

Attempts to bring about the reaction of the simplest diene (allene) with dialkyl aluminum hydrides led to no definite organoaluminum compounds 123). Little is known so far about the reaction of alkenes containing conjugated double bonds (butadiene 290), isopropene, etc.) with dialkyl alanes. Diisobutylalane and butadiene gave products whose hydrolysis... 

Organoaluminum reagents also undergo a variety of synthetically useful reactions with alkynes. The addition of dialkylaluminum hydrides to alkynes is a stereospecific cis addition. Vinylalanes that are capable of being converted to substituted alkenes by reaction with electrophilic reagents are formed. 

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