The Synthesis of Substituted Ferrocenes and other π‐Cyclopentadienyl‐Transition Metal Compounds

The discovery of dicyclopentadienyliron (ferrocene) in 1951 led to the development of an entirely new area of organometallic chemistry that of the pi-metallohydrocarbons. Representative compounds are the pi-metalloarenes such as dibenzenechromium, the pi-methallopseudoarenes such as ferrocene, and the pi-metalloolefin complexes such as butadiene iron tricarbonyl Since there is a great amount of literature available at this time, the treatment here is limited to three dimensions: to include only compounds containing cyclopentadienyl rings, of these to include only those which have shown to undergo aromatic substitution,reactions and within this group only synthetic aspects of their chemistry. This nearly restricts the discussion to syntheses of substituted ferrocenes. Keywords: substituted ferrocenes; pi-cyclopentadienyl-transition metal compounds; intermediates; cyclopentadienes; ruthenocene; osmocene; cyclopentadienylmanganese tricarbonyl. metal cyclopenatdienyl carbonyls; nitrosyl dicarbonyls; syntheses; ferrocene; experimental procedures