The Fries rearrangement uses a Lewis or Brӧnsted acid to synthesize ortho- and/or para substituted phenolic ketones and aldehydes from phenolic esters. First an acylium cation is produced, which facilitates an electrophilic aromatic substitution to afford the ortho- and/or para-product. The ortho product is favored with high temperatures and no...
The Kumada cross-coupling reaction uses a palladium or nickel catalyst to couple an organohalide and a Grignard or organolithium reagent. The mechanism follows the expected oxidative addition-reductive elimination cycle. Reagents: Catalytic Palladium or Nickel Reactant: Organohalide, Organomagnesium or Organolithium Product: Coupled Product Type of Reaction: C-C Cross-Coupling Lab Tips Organolithium...
The Finkelstein reaction uses acetone and a metal halide salt to exchange the halogen atom of an alkyl halide for another halogen atom via an SN2 reaction. The substituted metal halide being less soluble than the original metal halide in acetone (Le Chatelier’s principle) drives the reaction forward. Reagents: Acetone,...
The Eschenmoser-Claisen rearrangement uses heat to produce an γ,δ-unsaturated amide from an allylic alcohol and N,N-dimethylacetamide dimethyl acetal. First N,N-dimethylacetamide dimethyl acetal loses a methoxide ion to make an iminium ion, which is attacked by the allylic alcohol. Formation of a second iminium ion, followed by a proton abstraction, results...
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...
The Appel reaction uses a carbon tetrahalomethane and triphenylphosphine to convert a primary or secondary alcohol to an alkyl halide. First triphenylphosphine forms a phosphonium ion by abstracting a halogen from carbon tetrahalomethane. The alcohol then attacks the phosphonium ion, generating an oxyphosphonium intermediate. An SN2 displacement by the halide...