Unexpected Formation of a Molecular Tetraalkyl Nickel Complex from an Olefin/Nickel(0) System

Klein, Hans‐Friedrich; Kraikivskii, P. B.

doi:10.1002/anie.200805499

Cited by 16 publications

(7 citation statements)

References 19 publications

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“…25 In mechanism D, ( L )Ni II (Ar)(X) would react with an alkyl radical that originated from an alkyl halide. While oxidative addition of an alkyl halide, as in C, may 26 or may not 27 involve an alkyl radical intermediate, mechanism D must involve a radical intermediate.…”

Section: Resultsmentioning

confidence: 99%

Mechanism and Selectivity in Nickel-Catalyzed Cross-Electrophile Coupling of Aryl Halides with Alkyl Halides

2013

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The direct cross-coupling of two different electrophiles, such as an aryl halide with an alkyl halide, offers many advantages over conventional cross-coupling methods that require a carbon nucleophile. Despite its promise as a versatile synthetic strategy, a limited understanding of the mechanism and origin of cross selectivity has hindered progress in reaction development and design. Herein, we shed light on the mechanism for the nickel-catalyzed cross-electrophile coupling of aryl halides with alkyl halides and demonstrate that the selectivity arises from an unusual catalytic cycle that combines both polar and radical steps to form the new C-C bond.

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Section: Resultsmentioning

confidence: 99%

Mechanism and Selectivity in Nickel-Catalyzed Cross-Electrophile Coupling of Aryl Halides with Alkyl Halides

2013

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“…142 A recent study concludes that polyorganyl nickel complexes, where the σ-bonded organic group can be used as the ligand for stabilization of the catalytically active form of organonickel catalysts, can be formed in the reaction medium during the catalytic process. 143,144 Our recent study of the direct involvement of electrochemically synthesized 145 organonickel complexes of the type [NiBr(aryl)(bpy)] in the catalytic processes of ethylene oligomerization showed that these species are highly efficient precatalysts for catalytic processes. 8,146 The experiments performed showed that the presence of an organic group attached to the nickel atom greatly increases the catalytic activity of the nickel complex in comparison with related binary nickel complexes based on diimine ligands.…”

Section: ■ Properties Of Organonickel Complexesmentioning

confidence: 99%

Electrochemical Synthesis and Properties of Organonickel σ-Complexes

2014

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The organonickel complexes are organometallic compounds containing a Ni−C σ-bond (σ-complexes). These species are very reactive and have been mainly characterized as the intermediates of catalytic processes of cross coupling and homocoupling involving organic and elementoorganic substrates such as organic halides, chlorophosphines, unsaturated hydrocarbons, etc. Thus, only a limited number of these complexes have been isolated and characterized as the free stable species. Although the organonickel complexes have been known since the 1960s, the chemistry of these species is currently at the beginning stages of development. The interest of the researchers in this class of compounds has significantly increased over the past decade, resulting in a plethora of scientific papers published on this topic. At the same time, electrochemical methods have become more and more popular in modern synthetic chemistry, due to easy access to high reactive intermediates, including organometallic species, which can be selectively generated in situ and used for subsequent synthetic processes. This review summarizes the elaborated electrochemical approaches for the preparation of organonickel complexes, including a discussion of the important role of the electrochemical cell construction and the influence of the electrode material nature on the electrochemical process. In order to give more insight into the importance of organonickel complexes in synthetic chemistry and introduce the reader to this problem of organometallic chemistry, focused on the development of new synthetic protocols for preparation of stable organonickel complexes, an overview of the most important catalytic processes proceeding with participation of these highly reactive intermediates and the main types of organonickel complexes are presented. However, in this review organonickel complexes will be limited by examples in which the organic fragment is singly bonded to the nickel center, because these species are responsible for the catalytic reactions.

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“…The first homoleptic Ni IV complex 5 was made via two oxidative couplings of 4 with [Ni 0 (COD) 2 ] (COD = 1,5-cyclooctadiene) allowing to build the spirocyclic motif in 5 (Scheme 2) [38,39]. 5 was characterized using NMR and XRD, and proved stable upon heating or exposure to air.…”

Section: Introductionmentioning

confidence: 99%

High-Valent NiIII and NiIV Species Relevant to C–C and C–Heteroatom Cross-Coupling Reactions: State of the Art

Nebra

2020

Molecules

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Ni catalysis constitutes an active research arena with notable applications in diverse fields. By analogy with its parent element palladium, Ni catalysts provide an appealing entry to build molecular complexity via cross-coupling reactions. While Pd catalysts typically involve a M0/MII redox scenario, in the case of Ni congeners the mechanistic elucidation becomes more challenging due to their innate properties (like enhanced reactivity, propensity to undergo single electron transformations vs. 2e− redox sequences or weaker M–Ligand interaction). In recent years, mechanistic studies have demonstrated the participation of high-valent NiIII and NiIV species in a plethora of cross-coupling events, thus accessing novel synthetic schemes and unprecedented transformations. This comprehensive review collects the main contributions effected within this topic, and focuses on the key role of isolated and/or spectroscopically identified NiIII and NiIV complexes. Amongst other transformations, the resulting NiIII and NiIV compounds have efficiently accomplished: i) C–C and C–heteroatom bond formation; ii) C–H bond functionalization; and iii) N–N and C–N cyclizative couplings to forge heterocycles.

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Unexpected Formation of a Molecular Tetraalkyl Nickel Complex from an Olefin/Nickel(0) System

Cited by 16 publications

References 19 publications

Mechanism and Selectivity in Nickel-Catalyzed Cross-Electrophile Coupling of Aryl Halides with Alkyl Halides

Mechanism and Selectivity in Nickel-Catalyzed Cross-Electrophile Coupling of Aryl Halides with Alkyl Halides

Electrochemical Synthesis and Properties of Organonickel σ-Complexes

High-Valent NiIII and NiIV Species Relevant to C–C and C–Heteroatom Cross-Coupling Reactions: State of the Art

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