An unprecedented hydride abstraction from tricarbonyl[ethyl exo-3-[1-4-η-1,3-cyclohexadien-5-yl]propionate]iron complex

The addition of triphenylcarbenium hexafluorophosphate to the title complex gives tricarbonyl(η5-cyclohexadienylium)iron hexafluorophosphate with a side chain at the C-1 position of the ring. Intramolecular cyclization of the cation using sodium- or calcium- hydride generates a hetero spiro[4.5]decane derivative.