The electrophilic substitution of ferrocene by protonated carbonyl compounds

The α-ferrocenylalkyl caebenium ions are formed from ferrocene and carbonyl compounds in strongly acidic media, in particular mixtures of fluorosulfuric acid and trichloroacetic acid. The α-ferrocenylalkyl carbenium ions are scavenged by nucleophiles or bases. The addition of nucleophiles produces the corresponding α-substituted ferrocenyl alkanes. Proton abstraction by base from the β-position leads to the ferrocenylethene derivatives.Such electrophilic substitutions of ferrocene by carbonyl compounds, followed by suitable scavengeing of the α-ferrocenylalkyl carbenium ion, form the basis of one-pot syntheses of various ferrocene derivatives.