Electrophilic Attack on the Ligands

The Friedel-Crafts acylation of the cyclopentadienyl rings on ferrocene occurs about a million times faster than the corresponding acylation of benzene. The AICI3 catalyst reacts with acetyl chloride to make AIC and the strong electrophile CH3C =0, which then attacks the ring system. The r-MOs on the Cp ligand are 

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The authors point out that the dependence of the site of electrophilic attack on the ligand trans to the hydride in the model systems may be important with respect to alkane activation. If the information is transferable to Pt-alkyls, protonation at the metal rather than the alkyl should be favored with weak (and hard ) a-donor ligands like Cl- and H20. These are the ligands involved in Shilov chemistry and so by the principle of microscopic reversibility, C-H oxidative addition may be favored over electrophilic activation for these related complexes. 

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