Iron, tricarbonyl formylation Friedel-Crafts acetylation

Reaction of Complex III with acetyl chloride and aluminum chloride under typical Friedel-Crafts conditions affords acetylcyclobutadiene-iron tricarbonyl (VII) in high yields. The corresponding benzoyl derivative is similarly prepared with benzoyl chloride. Formylation with AT-methyl-formanilide and POCI3 produces cyclobutadienecarboxaldehyde-iron tricarbonyl (VIII), while chloromethylation with formaldehyde and HCl affords the chloromethyl derivative (IX). 

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