Electroreductive Synthesis of Nickel(0) Complexes**

Rubel, Camille Z.; Cao, Yilin; El‐Hayek Ewing, Tamara; Laudadio, Gabriele; Beutner, Gregory L.; Wisniewski, Steven R.; Wu, Xiangyu; Baran, Phil S.; Vantourout, Julien C.; Engle, Keary M.

doi:10.1002/anie.202311557

Cited by 4 publications

(3 citation statements)

References 72 publications

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“…A range of additional transformations are emerging as opportunities toward scalable processes (e.g., electrochemical trifluoromethylation of heterocycles, hydrogenations − ) that may be of high interest to pharma. The electrosynthesis of catalysts , and ligands , for catalysis and the deployment of asymmetric electrocatalytic methods are also of interest, but examples of these on large scale are still scarce. The development of electrosynthetic processes in green solvents is also of interest.…”

Section: Discussionmentioning

confidence: 99%

Overview of Recent Scale-Ups in Organic Electrosynthesis (2000–2023)

Lehnherr,

Chen

2024

Org. Process Res. Dev.

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This review summarizes examples of organic electrosynthesis from the peer-reviewed literature from 2000 to 2023 that have been conducted on scales of 20 g or above. A significant portion of these examples were conducted on a ≤100 g scale, while detailed reports of kilogram-scale electrosynthesis remain scarce in the pharmaceutical industry. In addition to the chemical transformation, this review also highlights the type of reactor used and a projected productivity metric as ways to compare the different reports. The selected examples of organic electrosynthesis scale-ups described herein also illustrate the remaining challenges currently preventing the routine use of large-scale electrosynthesis in the pharmaceutical industry.

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Section: Discussionmentioning

confidence: 99%

Overview of Recent Scale-Ups in Organic Electrosynthesis (2000–2023)

Lehnherr,

Chen

2024

Org. Process Res. Dev.

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“…Ni(COD)(DQ) can be synthesized by quantitative ligand displacement of one COD with DQ, reduction of Ni(acac) 2 in the presence of COD, followed by a solvent swap and addition of DQ, or electrochemically, accessing Ni(COD) 2 via a cathodic reduction followed by addition of DQ. 1,38 Crystallographic data of Ni(COD)(DQ) shows distortion of DQ upon coordination, with the four methyl substituents puckering toward and the two carbonyl groups pointing away from the nickel center (Scheme 2A). 11 This distortion augments metal−ligand bond strength through geometrically enhanced metal−ligand overlap.…”

Section: Rediscovery Of Nickel(cod)(dq)mentioning

confidence: 99%

Section: Rediscovery Of Nickel(cod)(dq)mentioning

confidence: 99%

Benchtop Nickel Catalysis Invigorated by Electron-Deficient Diene Ligands

Rubel,

He,

Wisniewski

et al. 2024

Acc. Chem. Res.

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Metrics & MoreArticle Recommendations CONSPECTUS: Due to the rarity of precious metals like palladium, nickel catalysis is becoming an increasingly important player in organic synthesis, especially for the formation of bonds with sp 3 -hybridized carbon centers. Traditionally, catalytic processes involving active Ni( 0) species have relied on Ni(COD) 2 or in situ reduction of Ni(II) salts. However, Ni(COD) 2 is an air-and temperature-sensitive material that requires use in an inertatmosphere glovebox, and in situ reduction protocols of Ni(II) salts using metallic or organometallic reductants add additional complications to reaction development. This Account chronicles the development of air-stable Ni(0) precursors as replacements for Ni(COD) 2 or in situ reduction. Based on Schrauzer's seminal discovery of Ni(COD)(DQ) as an air-stable zerovalent organonickel complex, our research laboratories at Scripps Research and Bristol Myers Squibb have developed a class of precatalysts based on the Ni(COD)(EDD) (EDD = electron-deficient diene) framework, relying on the steric and electronic properties of the supporting diene to render the metal center stable to air, moisture, and even silica gel but reactive to ligand substitution and redox changes. The stable Ni(0) complexes can be accessed through ligand exchange with Ni(COD) 2 , through reduction of Ni(acac) 2 using DIBAL-H, or electrochemically via cathodic reduction of Ni(acac) 2 to Ni(COD) 2 , followed by addition of an EDD ligand in one pot. As a toolkit, the complexes demonstrate reactivity that is equivalent or enhanced compared to Ni(COD) 2 , catalyzing C−C and C−N cross-couplings, Miyaura borylations, C−H activations, and other transformations. Since the initial report on Ni(COD)(DQ), its reactivity in C(sp 2 )−CN activation, metallophotoredox, and electric field-induced cross-coupling have also been demonstrated. By incorporating the precatalyst toolkit into reaction discovery campaigns, our laboratories have been able to perform C(sp 3 )− S(alkyl) couplings and metallonitrenoid carboamination, both of which represent challenging transformations that were inaccessible with traditional phosphine, nitrogen, or electron-deficient olefin ligands. Computational and experimental studies demonstrate how the quinone ligands are hemilabile, adopting η 1 (O)-bound geometries to relieve steric strain or stabilize transition states and intermediates; redox-active, able to transiently oxidize the metal center; and electron-withdrawing or -donating, depending on metal oxidation state and coordination geometry. These studies show how the ligands enable key steps in catalysis beyond imparting airstability. Since our report documenting the catalytic activity of Ni(COD)(DQ), many other laboratories have also observed unique reactivity with this precatalyst. Ni(COD)(DQ) was found to offer superior reactivity to Ni(COD) 2 in C−N cross coupling to form N,N-diaryl sulfonamides and in preparation of biaryls from aryl halides and benzene through a Ni-mediated, base-assisted homolytic a...

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Electrochemical Approach Toward Mesoionic 1,2,3‐Triazole 1‐Imines

Shuvaev,

Feoktistov,

Teslenko

et al. 2024

Adv Synth Catal

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Synthetic electrochemistry may establish direct routes to a preparation of a plethora of organic substances, which are hardly accessible by conventional experimental techniques. Herein, we present an electrochemically‐driven method for an assembly of a broad range of rare heterocyclic mesoionic entities – 1,2,3‐triazole 1‐imines. These nitrogen heterocycles were prepared through a transition‐metal‐ and exogenous oxidant‐free strategy using a C/Ni electrode pair. Over 30 examples of thus synthesized 1,2,3‐triazole 1‐imines illustrate selectivity and practical utility of this approach. Key solvent‐controlled reactivity patterns for the formation of the triazole imine scaffold were revealed indicating a modulation ability of the developed approach. These experimental findings were additionally justified based on cyclic voltammetry (CV) data and density functional theory (DFT) calculations. Moreover, according to differential scanning calorimetry (DSC) data, some of the prepared 1,2,3‐triazole 1‐imines correspond to the thermally stable species with an onset decomposition temperature up to 190 oC.

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Electroreductive Synthesis of Nickel(0) Complexes**

Cited by 4 publications

References 72 publications

Overview of Recent Scale-Ups in Organic Electrosynthesis (2000–2023)

Overview of Recent Scale-Ups in Organic Electrosynthesis (2000–2023)

Benchtop Nickel Catalysis Invigorated by Electron-Deficient Diene Ligands

Electrochemical Approach Toward Mesoionic 1,2,3‐Triazole 1‐Imines

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