Reaction of aldehydes and ketones with ferrocene, in the presence of trifluoroacetic acid, afforded a series of stable long lived alpha-ferrocenylalkyl carbocations which were characterized by 13C-NMR spectroscopy. When this reaction was attempted using tetraphenylcyclopentadienone, quite unexpectedly the corresponding dihydro derivative 3 was isolated, in very good yield. Formation of this compound may require ferrocene acting as a reducing agent.
ferrocene; alpha-ferrocenyl carbocations; 13C-NMR of alpha-ferrocenylalkyl carbocations
