Gold-Catalyzed C–H Bond Functionalization of Metallocenes: Synthesis of Densely Functionalized Ferrocene Derivatives

A convenient
process for the direct functionalization of ferrocene that exploits
the high electrophilic character of gold–vinyl carbenoids catalytically
generated from vinyldiazo compounds and gold complexes is reported.
This process takes place with complete regioselectivity (vinilogous
reactivity). The synthesis of the corresponding ruthenocene analogues
has also been achieved. Preliminary studies on the reactivity of these
new organometallic compounds seem to suggest that the presence of
the adjacent ferrocenyl group confers a specific reactivity on the
functionalized carbon chain manifested in the easy dry state aerobic
allylic oxidation.