Structure and reactivity of some carbonium ion derivatives of [alkyl-(cyclo-octatetraenyl)methanol]tricarbonyliron

Abstract

Treatment of the title compounds, [Fe(CO)₃{C₈H₇C(OH)HR}](R = Et or Buⁿ) with Ph₃CBF₄ or HPF₆ gives in almost quantitative yield the salts [Fe(CO)₃{C₈H₇CH(R)}]X (X = BF₄ or PF₆). On the basis of ¹H n.m.r. spectroscopic evidence, the structure of these salts is thought to involve a pentadienyl fragment and an unto-ordinated double bond within the eight-membered ring system and an exocyclic double bond. Some reactions of these salts with nucleophilic reagents are also described.