Tebbe's reagent

Tebbe's reagent is the organometallic compound with the formula (C₅H₅)₂TiCH₂ClAl(CH₃)₂. It is used in the methylidenation of carbonyl compounds, that is it converts organic compounds containing the R₂C=O group into the related R₂C=CH₂ derivative. It is a red solid that is pyrophoric in the air, and thus is typically handled with air-free techniques. It was originally synthesized by Fred Tebbe at DuPont Central Research.

Tebbe's reagent contains two tetrahedral metal centers linked by a pair of bridging ligands. The titanium has two cyclopentadienyl ([C
₅H
₅]
, or Cp) rings and aluminium has two methyl groups. The titanium and aluminium atoms are linked together by both a methylene bridge (-CH₂-) and a chloride atom in a nearly square-planar (Ti–CH₂–Al–Cl) geometry. The Tebbe reagent was the first reported compound where a methylene bridge connects a transition metal (Ti) and a main group metal (Al).