Effect of 6,6′-Substituents on Bipyridine-Ligated Ni Catalysts for Cross-Electrophile Coupling

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(9), P. 6897 - 6914

Published: April 19, 2024

A family of 4,4′-tBu2-2,2′-bipyridine (tBubpy) ligands with substituents in either the 6-position, 4,4′-tBu2-6-Me-bpy (tBubpyMe), or 6 and 6′-positions, 4,4′-tBu2-6,6′-R2-bpy (tBubpyR2; R = Me, iPr, sBu, Ph, Mes), was synthesized. These were used to prepare Ni complexes 0, I, II oxidation states. We observed that 6′-positions tBubpy ligand impact properties complexes. For example, bulkier 6,6′-positions better stabilized (tBubpyR2)NiICl species resulted a cleaner reduction from (tBubpyR2)NiIICl2. However, hindered prevented coordination tBubpyR2 Ni0(cod)2. In addition, by using type (tBubpyMe)NiCl2 (tBubpyR2)NiCl2 as precatalysts for different XEC reactions, we demonstrated 6,6′-substituents lead major differences catalytic performance. Specifically, while (tBubpyMe)NiIICl2 is one most active catalysts reported date can facilitate reactions at room temperature, lower turnover frequencies containing ligands. detailed study on intermediates (tBubpy)Ni(Ar)I (tBubpyMe2)Ni(Ar)I revealed several factors likely contributed activity. whereas are low spin relatively stable, high-spin less stable. Furthermore, captures primary benzylic alkyl radicals more slowly than (tBubpy)Ni(Ar)I, consistent activity former catalysis. Our findings will assist design tailor-made Ni-catalyzed transformations.

Language: Английский

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Electro-reductive carboxylation of C Cl bonds in unactivated alkyl chlorides and polyvinyl chloride with CO2

Chinese Chemical Letters, Journal Year: 2024, Volume and Issue: 35(12), P. 110104 - 110104

Published: June 8, 2024

Language: Английский

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Achieving Nickel-Catalyzed Reductive C(sp²)–B Coupling of Bromoboranes via Reversing the Activation Sequence

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(11), P. 7210 - 7215

Published: March 4, 2024

Transition metal-catalyzed reductive cross-couplings to build C–C/Si bonds have been developed, but the cross-coupling create C(sp2)–B bond has not explored. Herein, we describe a nickel-catalyzed between aryl halides and bromoboranes construct bond. This protocol offers convenient approach for synthesis of wide range boronate esters, using readily available starting materials. Mechanistic studies indicate that key success reaction is activation B–Br with Lewis base such as 2-MeO-py. The ensures will react active nickel(I) catalyst prior halides, which different from sequence general C(sp2)–C/Si cross-coupling, where oxidative addition an halide proceeds first. Notably, this minimizes production undesired homocoupling byproduct without requirement excessive quantities either substrate.

Language: Английский

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Synergistic Photoredox/Palladium Catalyzed Enantioconvergent Carboxylation of Racemic Heterobiaryl (Pseudo)Halides with CO₂

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 64(1)

Published: Aug. 16, 2024

Herein, we report a synergistic photoredox/palladium catalytic system for the efficient enantioconvergent synthesis of axially chiral esters from racemic heterobiaryl (pseudo)halides (bromides/triflates) with CO

Language: Английский

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Visible Light-Induced, Nickel-Catalyzed Late-Stage 4-Alkylation of Hantzsch Esters with Alkyl Bromide

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(15), P. 10987 - 10997

Published: July 22, 2024

Herein, visible light-induced, nickel-catalyzed direct functionalization of the Hantzsch esters (HEs) with readily accessible alkyl bromides has been successfully achieved by taking advantage HE as reductant and substrate through an aromatization-dearomatization process. In this strategy, single electron reduction reactive Ni(I) species is essential for success late-stage transformation. A wide range 4-alkyl-1,4-dihydropyridines were rapidly assembled in moderate to good yields under mild conditions, rendering photoinduced approach attractive synthetic medicinal chemistry.

Language: Английский

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Photoredox Nickel-Catalyzed Radical Cyclization of N-Arylacrylamides with Alkyl Bromides

Organic & Biomolecular Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

We present a photoredox nickel-catalyzed intermolecular cyclization between N -arylacrylamides and readily accessible alkyl bromides, which affords diverse range of 3,3-disubstituted oxindoles in moderate to high yields.

Language: Английский

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Metallaphotoredox-catalyzed alkynylcarboxylation of alkenes with CO2 and alkynes for expedient access to β-alkynyl acids

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Feb. 21, 2025

Carboxylation with CO2 offers an attractive and sustainable access to valuable carboxylic acids. Among these methods, direct C−H carboxylation of terminal alkynes has attracted much attention for one-carbon homologation alkynes, enabling rapid synthesis propiolic In contrast, the multi-carbons construct important non-conjugated alkynyl-containing acids not been reported. Herein, we present alkynylcarboxylation alkenes via photoredox copper dual catalysis. This protocol provides a practical method form alkynyl from readily available CO2. Additionally, this approach also features mild (room temperature, 1 atm CO2) redox-neutral conditions, high atom step economy, good functional group tolerance, selectivities. Moreover, diverse transformations β-alkynyl acid products bioactive molecule (GPR40/FFA1 agonist) further illustrate synthetic utility methodology. The report multi-carbon is rare. authors catalysis, affording

Language: Английский

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Nickel/Photoredox Dual-Catalyzed, Regioselective 1,2-Carboacylation of Alkenes via Synergistic Alkyl and Benzoyl Radical Coupling

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: May 2, 2025

A regioselective 1,2-carboacylation protocol of alkenes via nickel/photoredox dual catalysis has been successfully developed under mild conditions. wide range alkyl bromides, α-oxocarboxylic acids, and styrenes proved to be compatible the optimized conditions, affording corresponding products in up 91% yields. Mechanistically, key success this approach is temporal orchestration radical generation: nickel-catalyzed halogen atom transfer (XAT) for bromides photoredox-driven decarboxylation acids.

Language: Английский

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Ni-catalysed remote C(sp3)–H functionalization using chain-walking strategies

Nature Reviews Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 1, 2024

Language: Английский

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Introducing Type Ⅲ Metal Complex-Stabilized Olefin Radical Cation Induced Addition: A New Mechanism for Palladium-Catalyzed Wacker-Type Oxidation of Terminal Alkenes

Published: March 5, 2024

To expand the substrate scope of recently named “Radical Cation Induced Addition (RCIA)”, allowing functionalization inactivated alkenes, concept “metal complex-stabilized olefin RCIA” as a type III RCIA is introduced here, with rational design on delocalization radical spin via metal-olefin interaction and through space other ligands. The feasibility Pd-olefin cation complex one-electron oxidation enabled by an oxidant demonstrated in Pd-catalyzed Wacker-type terminal alkenes. new mechanisms involved “Pd(II) to Pd(I) catalytic cycle” matches reported kinetic data both Wacker process Tsuji-Wacker olefins ketones and/or aldehydes, it could explain long-time unexplained phenomenon water nucleophilic attack onto negatively charged π-olefin coordinated Pd atom. Furthermore, mechanisms, stereochemistry debated syn/anti regioselective control for either or aldehydes would also be well explainable. A “on interactions” too proposed root anti-Markovnikov selectivity resulted “through conjugation”. Implications recyclable precatalysts water-soluble ligand aldehyde selective “in-situ surfactant”, implications domino/one-pot reactions toward sustainable molecules functionalities starting from olefins, merging organocatalysis, are included.

Language: Английский

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