Hydroalumination, Carboalumination, Hydrozirconation, and Related Reactions

A large number of procedures that involve carbon-carbon bond formation have been developed based on organoboranes. These reactions are considered in Chapter 9. 

With trialkylaluminum compounds, the addition reaction is called carboalumination. As discussed below, this reaction requires a catalyst to proceed. 

Computational studies of both hydroalumination and carboalumination have indicated a four-center TS for the addition.220 The aluminum reagents, however, have more nucleophilic character than do boranes. Whereas the TS for hydroboration is primarily electrophilic and resembles that for attack of CH3+ on a double bond, the 

Electrophilic Additions to Carbon-Carbon Multiple Bonds 

Effective catalysts have recently been developed for the addition of trialkyl-aluminum reagents to alkenes (carboalumination). 6 -(Pentamethylcyclopentadienyl) zirconium dimethylide activated by fra-(pentafluorophenyl)boron promotes the addition of trimethylaluminum to terminal alkenes.221 

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