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Many mechanisms exist reflecting the myriad types of cross-couplings, including those that do not require metal catalysts. [7] Often, however, cross-coupling refers to a metal-catalyzed reaction of a nucleophilic partner with an electrophilic partner. Mechanism proposed for Kumada coupling (L = Ligand, Ar = Aryl).
In one important reaction type, a main group organometallic compound of the type R-M (where R = organic group, M = main group centre metal atom) reacts with an organic halide of the type R'-X with formation of a new carbon-carbon bond in the product R-R'. The most common type of coupling reaction is the cross coupling reaction. [1] [2] [3]
The Suzuki reaction or Suzuki coupling is an organic reaction that uses a palladium complex catalyst to cross-couple a boronic acid to an organohalide. [1] [2] [3] It was first published in 1979 by Akira Suzuki, and he shared the 2010 Nobel Prize in Chemistry with Richard F. Heck and Ei-ichi Negishi for their contribution to the discovery and development of noble metal catalysis in organic ...
In organic chemistry, the Kumada coupling is a type of cross coupling reaction, useful for generating carbon–carbon bonds by the reaction of a Grignard reagent and an organic halide. The procedure uses transition metal catalysts , typically nickel or palladium, to couple a combination of two alkyl , aryl or vinyl groups .
The Sonogashira reaction is a cross-coupling reaction used in organic synthesis to form carbon–carbon bonds. It employs a palladium catalyst as well as copper co-catalyst to form a carbon–carbon bond between a terminal alkyne and an aryl or vinyl halide .
The mechanism below shows the formation of poly(3-alkylthiophene) using a Ni initiator (L n can be 1,3-Bis(diphenylphosphino)propane (dppp)) and is similar to the conventional mechanism for Kumada coupling involving an oxidative addition, a transmetalation and a reductive elimination step.
These coupling reactions are made possible by modifying the backbone chemically. [10] Common reaction mechanisms used to synthesize these copolymers include free- radical polymerization , anionic polymerization , atom-transfer radical-polymerization , and living polymerization techniques.
Additionally, no reaction is shown to occur in the absence of primary C–H bonds, for example when cyclohexane is the substrate. Aliphatic C–H borylation Selective functionalization of a primary alkane bond is due to the formation of a kinetically and thermodynamically favorable primary alkyl-metal complex over formation of a secondary alkyl ...