text: Organometallic compounds undergo several important reactions:
  * associative and dissociative substitution
  * oxidative addition and reductive elimination
  * transmetalation
  * migratory insertion
  * β-hydride elimination
  * electron transfer
  * carbon-hydrogen bond activation
  * carbometalation
  * hydrometalation
  * cyclometalation
  * nucleophilic abstraction
  The synthesis of many organic molecules are facilitated by organometallic complexes. Sigma-bond metathesis is a synthetic method for forming new carbon-carbon sigma bonds. Sigma-bond metathesis is typically used with early transition-metal complexes that are in their highest oxidation state. Using transition-metals that are in their highest oxidation state prevents other reactions from occurring, such as oxidative addition. In addition to sigma-bond metathesis, olefin metathesis is used to synthesize various carbon-carbon pi bonds. Neither sigma-bond metathesis or olefin metathesis change the oxidation state of the metal. Many other methods are used to form new carbon-carbon bonds, including beta-hydride elimination and insertion reactions.