ChemInform Abstract: Nickel‐Catalyzed Cross‐Electrophile Coupling with Organic Reductants in Non‐Amide Solvents.

Anka‐Lufford, Lukiana L.; Huihui, Kierra M. M.; Gower, Nicholas J.; Ackerman, Laura K. G.; Weix, Daniel J.

doi:10.1002/chin.201652170

Cited by 2 publications

(3 citation statements)

References 9 publications

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“…Under the conditions reported by Weix et al,15a we explored a cross-electrophile coupling reaction between phenyl iodide and benzyl chloride using 1,4-dioxane as the solvent and TDAE as the reductant. In the absence of a radical generating cocatalyst, the reaction produced diphenylmethane in 40% yield (Table 1, Entry 1).…”

Section: Development Of a Dual Catalytic System For Cross-electrophile Couplingmentioning

confidence: 99%

A Widely Applicable Dual Catalytic System for Cross-Electrophile Coupling Enabled by Mechanistic Studies

et al. 2020

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A dual catalytic system for cross-electrophile coupling reactions between aryl halides and alkyl halides that features a Ni catalyst, a Co cocatalyst, and a mild homogeneous reductant is described. Mechanistic studies indicate that the Ni catalyst activates the aryl halide, while the Co cocatalyst activates the alkyl halide. This allows the system to be rationally optimized for a variety of substrate classes by simply modifying the loadings of the Ni and Co catalysts based on the reaction product profile. For example, the coupling of aryl bromides and aryl iodides with alkyl bromides, alkyl iodides, and benzyl chlorides is demonstrated using the same Ni and Co catalysts under similar reaction conditions but with different optimal catalyst loadings in each case. Our system is tolerant of numerous functional groups and is capable of coupling heteroaryl halides, diortho-substituted aryl halides, pharmaceutically relevant druglike aryl halides, and a diverse range of alkyl halides. Additionally, the dual catalytic platform facilitates a series of selective one-pot three-component cross-electrophile coupling reactions of bromo(iodo)arenes with two distinct

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Section: Development Of a Dual Catalytic System For Cross-electrophile Couplingmentioning

confidence: 99%

A Widely Applicable Dual Catalytic System for Cross-Electrophile Coupling Enabled by Mechanistic Studies

et al. 2020

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“…Reductant Screen.-Despite the rising interest in reductive coupling reactions, there are limited comparative studies exploring the impact of the nature of the reductant on catalysis. 19 To this end, a diverse series of reductants spanning a range of reduction potentials was evaluated in the carboxylation of 4-chloroanisole with (PPh 3 ) 2 Ni II Cl 2 as the precatalyst to explore the effect of reductant speciation and potential on catalyst performance (Table 2). Specifically, we tested the one electron organometallic, homogeneous reductants decamethylcobaltocene (Cp* 2 Co) 20 and cobaltocene (Cp 2 Co), 21 as well as the organic, homogeneous two-electron reductants tetrakis(dimethylamino)ethylene (TDAE) 22 and DMAP-OED, 23 which is an organic electron donor derived from 4-(dimethylamino)pyridine that was first reported by Murphy and co-workers.…”

Section: Empirical Investigation Into the Role Of Different Reagents mentioning

confidence: 99%

“…8n,9d Additionally, DMAP-OED can be prepared in two steps from relatively inexpensive starting materials (each less than $100/kg) and is a solid at room temperaure, 23 which makes it easier to work with than volatile liquid organic reductants such as TDAE. 19,26 From a mechanistic perspective, no catalysis was observed with DMAP-OED as the reductant in the absence of MnCl 2 . This indicates that when DMAP-OED is used in catalysis, the source of the electrons is decoupled from the production of MnCl 2 , unlike when Mn 0 is used the reductant.…”

Section: Empirical Investigation Into the Role Of Different Reagents mentioning

confidence: 99%

Development of an Improved System for the Carboxylation of Aryl Halides through Mechanistic Studies

et al. 2019

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The nickel-catalyzed carboxylation of organic halides or pseudohalides using carbon dioxide is an emerging method to prepare synthetically valuable carboxylic acids. Here, we report a detailed mechanistic investigation of these reactions using the carboxylation of aryl halides with (PPh 3) 2 Ni II Cl 2 as a model reaction. Our studies allow us to understand several general features of nickel-catalyzed carboxylation reactions. For example, we demonstrate that both a Lewis acid and halide source are beneficial for catalysis. To this end, we establish that heterogeneous Mn(0) and Zn(0) reductants are multifaceted reagents that generate noninnocent Mn(II) or Zn(II) Lewis acids upon oxidation. In a key result, a rare example of a well-defined nickel(I) aryl complex is isolated, and it is demonstrated that its reaction with carbon dioxide results in the formation of a carboxylic acid in high yield (after workup). The carbon dioxide insertion product undergoes rapid decomposition, which ca These three oxidation states correspond to the onbe circumvented by a ligand metathesis reaction with a halide source. Our studies have led to both a revised mechanism and the development of a broadly applicable strategy to improve reductive carboxylation reactions. A critical component of this strategy is that we have replaced the heterogeneous Mn(0) reductant typically used in catalysis with a well-defined homogeneous organic reductant. Through its use, we have increased the range of ancillary ligands, additives, and substrates that are compatible with the reaction. This has enabled us to perform reductive carboxylations at low catalyst loadings. Additionally, we demonstrate that reductive carboxylations of organic (pseudo)halides can be achieved in high yields in more practically useful, non-amide solvents. Our results describe a mechanistically guided strategy to improve reductive carboxylations through the use of a homogeneous organic reductant, which may be broadly translatable to a wide range of crosselectrophile coupling reactions.

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ChemInform Abstract: Nickel‐Catalyzed Cross‐Electrophile Coupling with Organic Reductants in Non‐Amide Solvents.

Abstract: A high‐yielding cross‐electrophile coupling of aryl or hetaryl halides with functionalized alkyl halides is examined.

Cited by 2 publications

References 9 publications

A Widely Applicable Dual Catalytic System for Cross-Electrophile Coupling Enabled by Mechanistic Studies

A Widely Applicable Dual Catalytic System for Cross-Electrophile Coupling Enabled by Mechanistic Studies

Development of an Improved System for the Carboxylation of Aryl Halides through Mechanistic Studies

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