Electrophilic aromatic substitution in ferrocene

Electrostatic potential map for ferrocene shows negatively-charged regions (in red) and positively-charged regions (in blue). 

The cyclopentadienyl rings in ferrocene display some of the same chemical behavior as benzene. For example, ferrocene undergoes Friedel-Crafts mono and di acylation reactions, but at different rates. 

Friedel-Crafts acylation involves electrophilic attack by acyl cation (CHsCO ) on the ring, and the ring s electronic character should indicate its susceptibility to attack. Compare electrostatic potential maps of ferrocene and acetylferrocene. Which molecule contains the most electron-rich ring Which acylation reaction should be faster Does an acetyl substituent enhance or diminish ring reactivity What should be the major product when ferrocene is combined with one equivalent of acetic anhydride  

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