The Knorr pyrazole synthesis uses a catalytic acid to convert a hydrazine and 1,3-dicarbonyl compound to pyrazoles.  The dicarbonyl deprotonates the acid and is subsequently attacked by the hydrazine to produce an imine. The second nitrogen of the hydrazine then attacks the second carbonyl group to form a second...

The Kolbe-Schmitt reaction uses a base, carbon dioxide, and an acid work-up to convert a phenol to an ortho- or para- hydroxy benzoic acid. First the base deprotonates the phenol, forming phenoxide, which attacks carbon dioxide. Tautomerization and an acid work-up yields the final product. A large counterion such as...

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...

What is Kumada Cross-coupling Reaction? 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. Reaction Summary: Reagents: Catalytic Palladium or Nickel Reactant: Organohalide, Organomagnesium or Organolithium Product: Coupled Product Type...

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...