Multicarbonylation of Cyclopentadienyl and Cycloheptatrienyl Anions by Fe(CO)5

Article abstract of DOI:10.1246/bcsj.66.934

The reaction of cyclopentadienyl anions with Fe(CO)5 in the presence of acyl chlorides or carboxylic anhydrides gave cyclic acyliron complexes <η⁵-C5H4C(OCOR)=C(OCOR)CO>Fe(CO)2 via triple carbonylation of the anions and a double acylation.The structure of <η⁵-C5H4C(OCOCH2CH3)=C(OCOCH2CH3)CO>Fe(CO)2 thus obtained was confirmed by the X-ray analysis.Diastereomers of indenyl derivative <η⁵-C9H6C(OCOCH2CH3)=C(OCOCH2CH3)CO>Fe(CO)(P(OCH3)3) were prepared by substitution of CO ligand with trimethyl phosphite and the structure of the diastereomers were characterized by NMR spectroscopy using 2D technique.Treatment of cycloheptatrienyl anion with Fe(CO)5 and acyl chloride resulted in double carbonylation to give <η⁵-C7H6C(OCOR)=C(OCOR)>Fe(CO)2.The mechanism of the reaction is proposed.