The Heck reaction produces a substituted alkene by cross-coupling the alkene with an organohalide in the presence of catalytic palladium. Oxidative addition of the alkyl or aryl halide to the palladium is followed by a syn migratory insertion of the alkene. Bond rotation facilitates a syn β-hydride elimination, and a base-mediated reductive elimination regenerates the catalyst.

  • Reagents: Catalytic Palladium, Ligand (e.g. Trialkyl- or Triarylphosphines, etc.), Base (2° or 3° Amine, KOAc, NaOAc, or NaHCO3)
  • Reactant: Organohalide [Aryl, Benzyl, Alkenyl, or Alkyl (with no β Hydrogens) and Halide (Cl, Br, I, OTf, OTs, N2+)], Alkene (Alkyl, Aryl, Alkenyl)
  • Product: Arylated or Alkenylated Olefin
  • Type of Reaction: Pd-Catalyzed Coupling

Lab Tips

  • Esters, ethers, carboxylic acids, nitriles, phenols, dienes are well tolerated on the olefin component, but allylic alcohols tend to rearrange.
  • Substrates with hydrogens on β-carbons tend to undergo β-hydride elimination affording olefins.
  • Aryl chlorides are slow to react, resulting in lower yields.
Kürti, L., Czakó, B. (2005). Strategic Applications of Named Reactions in Organic Synthesis; Background and detailed mechanisms. Burlington, MA: Elsevier Academic Press.


Top Citations

Original Paper

Related Reactions

  • Stille Cross-Coupling
  • Olefination

Related Compounds

  • Catalytic Palladium
By shuhan yang


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