Heck Reaction-百灵威

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 HaHCO₃)
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.

Mechanism

Olefination

Related Compounds

Grignard Reagents

Catalytic Palladium

Base

Heck Reaction

Lab Tips

Mechanism

Original Paper

Top Citations

Related Reactions

Related Compounds