page_title: Organotitanium compound
section_title: Titanocene derivatives
hierarchical_section_title: Organotitanium compound / Compounds / Titanocene derivatives
caption_attribution_description: English: better drawing of Cp2TiMe2
context_page_description: Organotitanium compounds in organometallic chemistry contain carbon-to-titanium chemical bonds. Organotitanium chemistry is the science of organotitanium compounds describing their physical properties, synthesis and reactions. They are reagents in organic chemistry and are involved in major industrial processes.
context_section_description: A particularly rich area of organotitanium chemistry involves derivatives of titanocene dichloride.  Tebbe's reagent (1978) is prepared from titanocene dichloride and trimethylaluminium. It is used as a methylenation agent for carbonyl compounds (conversion of R₂C=O to R₂C=CH₂). It is an alternative for Wittig reagents when the carbonyl group is sterically challenged or when it easily forms the enol.  Tebbe's reagent itself does not react with carbonyl compounds, but must first be treated with a mild Lewis base, such as pyridine, which generates the active Schrock carbene.
  Tebbe's reagent adds simple alkenes to give titanocyclobutanes, which can be regarded as stable olefin metathesis intermediates. These compounds are reagents in itself such as 1,1-bis(cyclopentadienyl)-3,3-dimethyltitanocyclobutane, the adduct of Tebbe's reagent with isobutene catalysed with 4-dimethylaminopyridine.
  The Petasis reagent or dimethyl titanocene (1990) is prepared from titanocene dichloride and methyllithium in diethyl ether. Compared to Tebbe's reagent it is easier to prepare and easier to handle. It is also a methylenation reagent.
  The Nugent-RajanBabu reagent is a one-electron reductant used in synthetic organic chemistry for the generation of alcohols via anti-Markovnikov ring-opening of epoxides, and is generated as a dimer [(η⁵-Cp)₂Ti(μ-Cl)]₂ and used in situ from titanocene dichloride.
caption: The Petasis reagent, [(η5-Cp)2Ti(CH3)2]
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