Home >  Products

Nickel Catalysts [Cross-coupling Reaction using Transition Metal Catalysts]

 Nickel catalysts are routinely used for cross-coupling reactions as well as palladium catalysts. In 1972, Kumada and Tamao had reported that nickel catalysts promoted cross-coupling reactions of Grignard reagents with aryl halides or vinyl halides with the proposal their catalytic cycle. The result of this research has contributed to further development of cross coupling reactions1).
 Nickel catalysts are generally inexpensive and show high activities even when using low reactive substrates in cross-coupling reactions. For example, in the presence of butyl lithium, zinc metal or phosphines as a co-reductant, NiCl2(dppf) catalyzed cross-coupling reactions of aryl chlorides/mesylates with aryl borates successfully proceeding to afford the desired biaryls in good yields.2) Recently, it has been reported that N-heterocyclic carbene (NHC)–nickel complexes show high catalytic activity in cross-coupling reactions.
==========================>>[SEE MORE INFORMATION]<<===========================
 
 On the other hand, similar to iron and cobalt catalysts, nickel catalysts are used for the cross coupling reactions of alkyl halides with organometallic species such as organomagnesium, organozinc and organoboric acid compounds. This synthetic means is effective for producing the carbon sp3 – carbon sp3 bond. In this reaction, phosphine ligands are less effective and an optimization of the reaction conditions suitable for each substrate was investigated. In a case using primary alkyl halides as a reactant, the coupling reactions are accelerated by using NMP as a solvent and addition of alkenes with electron-withdrawing groups. It is also effective to add butadienes as additives because the reactivity of the coupling reactions improves through the formation of nickel - bis-allyl complexes. The proceeding of cross-coupling reactions with secondary alkyl halides is harder relative to primary alkyl halides, so pyridyl-type chelate ligands such as phenanthrolines, Pybox, and diamines are used for promoting those reactions. This has been applied to asymmetric reactions and natural products synthesis.3)

Page Top