Recent advances in pincer–nickel catalyzed reactions

Dalton Transactions, Год журнала: 2021, Номер 50(10), С. 3394 - 3428

Опубликована: Янв. 1, 2021

The utility of pincer−nickel complexes in catalyzing reactions such as cross−coupling, oxidation, (de)hydrogenation, hydrofunctionalization, C−H activation and CO₂ functionalization has been reviewed from a synthetic mechanistic point view.

Язык: Английский

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NNN manganese complex-catalyzed α-alkylation of methyl ketones using alcohols: an experimental and computational study

Dalton Transactions, Год журнала: 2024, Номер 53(7), С. 3236 - 3243

Опубликована: Янв. 1, 2024

A quinoline-based pincer Mn catalyst for α-alkylation of methyl ketones using primary alcohols as alkyl surrogates is presented. The C–C bond formation reaction proceeds via a hydrogen auto-transfer protocol, generating water the only by-product.

Язык: Английский

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Nickel-Catalyzed Alkylation of Ketone Enolates: Synthesis of Monoselective Linear Ketones

The Journal of Organic Chemistry, Год журнала: 2018, Номер 84(2), С. 769 - 779

Опубликована: Дек. 14, 2018

Herein we have developed a Ni-catalyzed protocol for the synthesis of linear ketones. Aryl, alkyl, and heteroaryl ketones as well alcohols yielded monoselective in up to 90% yield. The catalytic was successfully applied gram-scale synthesis. For practical utility, applications steroid derivative, oleyl alcohol, naproxen alcohol were employed. Preliminary investigations involving isolation Ni intermediate defined Ni–H species series deuterium-labeling experiments performed.

Язык: Английский

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N–Alkylation of Amines Catalyzed by a Ruthenium–Pincer Complex in the Presence of in situ Generated Sodium Alkoxide

European Journal of Organic Chemistry, Год журнала: 2019, Номер 2019(40), С. 6855 - 6866

Опубликована: Сен. 21, 2019

We report the use of ruthenium–NNN‐pincer complexes type ( R2 NNN)RuCl 2 (PPh 3 ) (R = t Bu, i Pr, Cy and Ph) for catalytic N ‐alkylation primary amines under solvent‐free conditions. For first time, base that is required to promote these reactions generated in situ from alcohol by sodium. The resulting sodium alkoxide regenerates substrate while acting as water scavenger thus mitigating need an additional base. Among catalysts screened, Bu2 (0.02 mol‐%) gives very high turnovers good yields at 140 °C. catalyzed tolerates a variety amine substrates. While excellent turnover (29000) was obtained (0.002 alkylation aniline with cyclohexyl methanol, corresponding methylation p ‐anisidine also (12000). have been accomplished open‐vessel conditions net dehydrogenative coupling reaction. This protocol has used transform benzene‐1,2‐diamines benzimidazoles productivity (12000 turnovers). DFT studies indicate β‐hydride elimination rate‐determining (RDTS: 24.31 kcal/mol) dehydrogenation segment which endothermic, insertion imine 11.26 its hydrogenation exothermic.

Язык: Английский

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Solvent-Free N-Alkylation and Dehydrogenative Coupling Catalyzed by a Highly Active Pincer-Nickel Complex

Organometallics, Год журнала: 2020, Номер 39(11), С. 2162 - 2176

Опубликована: Май 22, 2020

The synthesis and characterization of a pincer-nickel complex the type (iPr2NNN)NiCl2(CH3CN) is reported here. We have demonstrated utility this (0.02 0.002 mol %) for catalytic N-alkylation amines using various alcohols. Under solvent-free conditions, while highest yield (ca. 90%) was obtained alkylation 2-aminopyridine with naphthyl-1-methanol, excellent turnovers (34000 TONs) were observed 4-methoxybenzyl alcohol. To demonstrate synthetic these systems, high-yield reactions (up to 98%) been probed representative substrates higher loading catalyst (4 %). DFT studies indicate that β-hydride elimination RDS alcohol dehydrogenation, N-alkylated product can be formed either via hydrogenation rate-determining σ-bond metathesis or by alcoholysis has imine insertion as RDS. All corresponding resting states HRMS (ESI) analysis. labeling experiments are also complementary show evidence involvement benzylic C–H bond in kCHH/kCHD value about 2.5. This method applied accomplish efficient (2000 dehydrogenative coupling leading benzimidazoles.

Язык: Английский

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First‐Row Transition‐Metal Catalyzed Acceptorless Dehydrogenation and Related Reactions: A Personal Account

The Chemical Record, Год журнала: 2021, Номер 21(12), С. 3839 - 3871

Опубликована: Авг. 20, 2021

Abstract The development of sustainable catalytic protocols that circumvent the use expensive and precious metal catalysts avoid toxic reagents plays a crucial role in organic synthesis. Indeed, direct employment simple abundantly available feedstock chemicals as starting materials broadens their synthetic application contemporary research. In particular, transition metal‐catalyzed diversification alcohols with various nucleophilic partners to construct wide range building blocks is powerful highly desirable methodology. Moreover, replacement by non‐precious less metals for selective transformations one main goals has been paid significant attention modern chemistry. view this, first‐row find extensive applications such hydrogenation, dehydrogenation, related reactions. Herein, we have disclosed our recent developments on base‐metal catalysis Mn, Fe, Co, Ni acceptorless dehydrogenation reactions its C−C C−N bond formation via hydrogen auto‐transfer (HA) coupling (ADC) These HA/ADC employ alcohol alkylating agents eliminate water and/or gas by‐products, representing atom‐efficient environmentally benign Furthermore, diverse complex molecules synthesis using are also overviewed. Overall, this account deals contribution efficient novel homogeneous well heterogeneous chemical

Язык: Английский

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Ligand-tuned cobalt-containing coordination polymers and applications in water

Green Chemistry, Год журнала: 2020, Номер 22(23), С. 8452 - 8461

Опубликована: Янв. 1, 2020

Co-CIA could realize the alkylation of ketones and alcohols, alcohols without extra bases organic solvents, while Co-NCIA was effective for synthesis 1-benzyl-2-aryl-1H-benzo[d]imidazoles from various phenylenediamine benzyl in water.

Язык: Английский

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Manganese-Catalyzed C(α)-Alkylation of Oxindoles with Secondary Alcohols via Borrowing Hydrogen

Organometallics, Год журнала: 2021, Номер 40(6), С. 627 - 634

Опубликована: Март 3, 2021

A general and efficient C(α)-alkylation of oxindoles with unactivated secondary alcohols as alkylating agents catalyzed by a newly developed NNN-Mn(II) complex is reported. Mechanistic studies illustrate that the importance NH moiety in M–L cooperation play very important roles during catalytic transformation.

Язык: Английский

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Nickel catalyzed sustainable synthesis of benzazoles and purines via acceptorless dehydrogenative coupling and borrowing hydrogen approach

Organic & Biomolecular Chemistry, Год журнала: 2021, Номер 19(33), С. 7217 - 7233

Опубликована: Янв. 1, 2021

Herein we report nickel-catalyzed sustainable synthesis of a few chosen five-membered fused nitrogen heterocycles such as benzimidazole, purine, benzothiazole, and benzoxazole via acceptorless dehydrogenative functionalization alcohols. Using bench stable, easy to prepare, inexpensive Ni(ii)-catalyst, [Ni(MeTAA)] (1a), featuring tetraaza macrocyclic ligand (tetramethyltetraaza[14]annulene (MeTAA)), wide variety polysubstituted derivatives were prepared coupling alcohols with 1,2-diaminobenzene, 4,5-diaminopyrimidine, 2-aminothiphenol, 2-aminophenol, respectively. A array benzimidazoles also borrowing hydrogen approach involving donors 2-nitroanilines acceptors. control experiments performed understand the reaction mechanism.

Язык: Английский

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Pincer-Nickel Catalyzed Selective Guerbet-Type Reactions

Organometallics, Год журнала: 2021, Номер 40(16), С. 2870 - 2880

Опубликована: Авг. 5, 2021

We report here the synthesis and characterization of a series NNN pincer-nickel complexes type (R2NNN)NiCl2(CH3CN) (R = iPr, tBu, Cy, Ph, p-F-C6H4) based on bis(imino)pyridine ligands. In solution, these are found to be equilibrium mixtures containing one two pincer ligands, respectively. While crystal structure former was reported by us recently for R we latter in this study p-F-C6H4. The considered pincer-Ni have been successfully employed accomplish catalytic β-alkylation several secondary alcohols with variety benzyl at 140 °C high yields unprecedented turnovers. A maximum 92% yield β-alkylated product 18 400 TON obtained reaction alcohol 1-(4-(trifluoromethyl)phenyl)ethane-1-ol presence 0.005 mol % (Ph2NNN)NiCl2(CH3CN) 5 NaOtBu after 24 h. exhibits zero-order dependence rate catalyst concentration first-order base, alcohol, 1-phenyl ethanol which points base-mediated aldol condensation as rate-determining step. Most intermediates involved catalysis identified HRMS. To best our knowledge, is first catalyzed and, hitherto, such turnovers not homogeneous molecular nickel-based catalyst.

Язык: Английский

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