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This reaction was the first example of a carbon-carbon bond-forming reaction that followed a Pd(0)/Pd(II) catalytic cycle, the same catalytic cycle that is seen in other Pd(0)-catalyzed cross-coupling reactions. The Heck reaction is a way to substitute alkenes. [2] [3] [4] [5]
The most common type of coupling reaction is the cross coupling reaction. [1] [2] [3] Richard F. Heck, Ei-ichi Negishi, and Akira Suzuki were awarded the 2010 Nobel Prize in Chemistry for developing palladium-catalyzed cross coupling reactions. [4] [5] Broadly speaking, two types of coupling reactions are recognized:
The Negishi coupling is a widely employed transition metal catalyzed cross-coupling reaction. The reaction couples organic halides or triflates with organozinc compounds, forming carbon-carbon bonds (C-C) in the process. A palladium (0) species is generally utilized as the catalyst, though nickel is sometimes used.
Pd(PPh 3) 4 is widely used as a catalyst for palladium-catalyzed coupling reactions. [7] Prominent applications include the Heck reaction, Suzuki coupling, Stille coupling, Sonogashira coupling, and Negishi coupling. These processes begin with two successive ligand dissociations followed by the oxidative addition of an aryl halide to the Pd(0 ...
[Pd 2 (dba) 3] is used as a source of soluble Pd(0), in particular as a catalyst for various coupling reactions. Examples of reactions using this reagent are the Negishi coupling, Suzuki coupling, Carroll rearrangement, and Trost asymmetric allylic alkylation, as well as Buchwald–Hartwig amination.
The Heck reaction is the palladium-catalyzed coupling of an aryl or alkenyl halide with an alkene to form a substituted alkene. [2] Intramolecular variants of the reaction may be used to generate cyclic products containing endo or exo double bonds. Ring sizes produced by the intramolecular Heck reaction range from four to twenty-seven atoms.
Cross-couplings are a subset of the more general coupling reactions. Often cross-coupling reactions require metal catalysts. One important reaction type is this: R−M + R'−X → R−R' + MX (R, R' = organic fragments, usually aryl; M = main group center such as Li or MgX; X = halide) These reactions are used to form carbon–carbon bonds but ...
The most typical class of reactions involves coupling between C–COOH and C–X bonds, however C–COOH and C–M cross-coupling, homo-coupling of carboxylic acids, heck coupling, and dehydrogenative cross-coupling can also be including in this class as they release CO 2. Heteroatom cross coupling reactions involving formation of C–N, C–S ...