Enantioselective Reductive Conjugate Alkenylation of α,β-Unsaturated Ketones and Amides via Nickel Catalysis

ACS Catalysis, Год журнала: 2024, Номер 14(8), С. 6228 - 6235

Опубликована: Апрель 10, 2024

Chiral nickel complexes promoted enantioselective reductive alkenylation of a range conjugated enones, using alkenyl bromides, triflates, and tosylates. The neutral condition was compatible with sensitive groups azaheteroaryl rings. Importantly, in products can be readily converted to functionalized alkyl via iron-catalyzed hydrofunctionalization. Some examples asymmetric N-enoyl pyrroles indoles were also included.

Язык: Английский

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Light Activation and Photophysics of a Structurally Constrained Nickel(II)–Bipyridine Aryl Halide Complex

Inorganic Chemistry, Год журнала: 2024, Номер 63(9), С. 4120 - 4131

Опубликована: Фев. 20, 2024

Transition-metal photoredox catalysis has transformed organic synthesis by harnessing light to construct complex molecules. Nickel(II)–bipyridine (bpy) aryl halide complexes are a significant class of cross-coupling catalysts that can be activated via direct excitation. This study investigates the effects molecular structure on photophysics these considering an underexplored, structurally constrained Ni(II)–bpy in which and bpy ligands covalently tethered alongside traditional unconstrained complexes. Intriguingly, is photochemically stable but features reversible Ni(II)–C(aryl) ⇄ [Ni(I)···C(aryl)•] equilibrium upon photoexcitation. When electrophile introduced during photoirradiation, we demonstrate preference for photodissociation over recombination, rendering parent Ni(II) source reactive Ni(I) intermediate. Here, characterize photochemical behavior kinetic analyses, quantum chemical calculations, ultrafast transient absorption spectroscopy. Comparison previously characterized indicates structural constraints considered here dramatically influence excited state relaxation pathway provide insight into characteristics excited-state Ni(II)–C bond homolysis radical reassociation dynamics. enriches understanding offers new possibilities designing customized photoactive precise synthesis.

Язык: Английский

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Ni-catalyzed enantioconvergent deoxygenative reductive cross-coupling of unactivated alkyl alcohols and aryl bromides

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Март 28, 2024

Abstract Transition metal-catalyzed enantioconvergent cross-coupling of an alkyl precursor presents a promising method for producing enantioenriched C(sp 3 ) molecules. Because alcohol is ubiquitous and abundant family feedstock in nature, the direct reductive coupling aryl halide enables efficient access to valuable compounds. Although several strategies have been developed overcome high bond dissociation energy C − O bond, asymmetric pattern remains unknown. In this report, we describe realization deoxygenative unactivated (β-hydroxy ketone) bromide presence NHC activating agent. The approach can accommodate substituents various sizes functional groups, its synthetic potency demonstrated through gram scale reaction derivatizations into other compound families. Finally, apply our convergent synthesis four β-aryl ketones that are natural products or bioactive

Язык: Английский

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Zirconaaziridine-Mediated Ni-Catalyzed Diastereoselective C(sp²)-Glycosylation

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(24), С. 16753 - 16763

Опубликована: Июнь 11, 2024

In the realm of organic synthesis, catalytic and stereoselective formation C-glycosidic bonds is a pivotal process, bridging carbohydrates with aglycones. However, inherent chirality saccharide scaffold often has substantial impact on stereoinduction imposed by chiral ligand. this study, we have established an unprecedented zirconaaziridine-mediated asymmetric nickel catalysis, enabling diastereoselective coupling bench-stable glycosyl phosphates range (hetero)aromatic glycal iodides as feasible electrophiles. Our developed method showcases broad scope high tolerance for various functional groups. More importantly, precise stereocontrol toward both anomeric configurations forming C(sp2)-glycosides can be realized simply utilizing popular bioxazoline (biOx) ligands in reductive Ni catalysis. Regarding operating mechanism, experimental computational studies support occurrence redox transmetalation leading to transient, bimetallic Ni–Zr species that acts potent efficient single-electron reductant process.

Язык: Английский

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Dual Nickel- and Photoredox-Catalyzed Asymmetric Reductive Cross-Couplings: Just a Change of the Reduction System?

Accounts of Chemical Research, Год журнала: 2024, Номер 57(14), С. 1997 - 2011

Опубликована: Июль 4, 2024

ConspectusIn recent years, nickel-catalyzed asymmetric coupling reactions have emerged as efficient methods for constructing chiral C(sp

Язык: Английский

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Nickel-catalyzed reductive formylation of aryl halides via formyl radical

Chinese Chemical Letters, Год журнала: 2024, Номер 35(12), С. 109783 - 109783

Опубликована: Март 20, 2024

Язык: Английский

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Unified Photocatalytic Strategy for the Cross-Coupling of Alcohols with Aryl Halides Enabled by Synergistic Nickel and Iron LMCT Catalysis

ACS Catalysis, Год журнала: 2024, Номер 14(17), С. 12757 - 12768

Опубликована: Авг. 9, 2024

The use of alcohol feedstock as a coupling partner in cross-coupling reactions offers an extraordinary potential for the efficient synthesis Csp3-rich complex molecular scaffolds. This prominent strategy relies on generation alkoxy radicals, which can react via various radical pathways to give carbon-centered radicals that be engaged C–C bond formation reactions. However, involving catalytic directly from native alcohols are highly challenging and scope existing methods remains particularly limited. Moreover, unified incorporate broad range with aryl halides is currently unavailable. Herein, we report general photocatalytic platform combines nickel iron ligand-to-metal charge transfer (LMCT) catalysis selective deconstructive Csp3–Csp3 cleavage arylation unactivated alcohols. protocol leverages ability photoinduced LMCT generate diversely substituted alcohols, enabling implementation bond-forming manifolds. These include dehydroxymethylative aliphatic remote cyclic yield alkyl ketones, methylation using tertiary methyl source. methodology practical engaging large variety commercially available under mild conditions, abundant catalysts. Mechanistic studies, including stoichiometric organometallic chemistry voltammetry, provide insights into crucial role ancillary ligand surrounding catalyst stabilizing both low- high-valent intermediates.

Язык: Английский

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Electronic Structures of Nickel(II)-Bis(indanyloxazoline)-dihalide Catalysts: Understanding Ligand Field Contributions That Promote C(sp²)–C(sp³) Cross-Coupling

Inorganic Chemistry, Год журнала: 2023, Номер 62(34), С. 14010 - 14027

Опубликована: Авг. 16, 2023

NiII(IB) dihalide [IB = (3aR,3a′R,8aS,8a′S)-2,2′-(cyclopropane-1,1-diyl)bis(3a,8a-dihydro-8H-indeno[1,2-d]-oxazole)] complexes are representative of a growing class first-row transition-metal catalysts for the enantioselective reductive cross-coupling C(sp2) and C(sp3) electrophiles. Recent mechanistic studies highlight complexity these ground-state cross-couplings but also illuminate new reactivity pathways stemming from one-electron redox their significant sensitivities to reaction conditions. For first time, diverse array spectroscopic methods coupled electrochemistry have been applied NiII-based precatalysts evaluate specific ligand field effects governing key Ni-based potentials. We experimentally demonstrate DMA solvent coordination catalytically relevant Ni complexes. Coordination is shown favorably influence redox-based steps prevent other deleterious equilibria. Combined with electronic structure calculations, we further provide direct correlation between intermediate frontier molecular orbital energies yields. Considerations developed herein use synergic electrochemical concepts catalyst design rationalization condition optimization.

Язык: Английский

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Nickel-Catalyzed Reductive Arylation of Redox Active Esters for the Synthesis of α-Aryl Nitriles: Investigation of a Chlorosilane Additive

The Journal of Organic Chemistry, Год журнала: 2024, Номер 89(22), С. 16161 - 16169

Опубликована: Янв. 10, 2024

A nickel-catalyzed reductive cross-coupling of redox active

Язык: Английский

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Electrochemical Reductive Cross-Coupling of Vinyl Bromides for the Synthesis of 1,3-Dienes

Organic Letters, Год журнала: 2024, Номер 26(5), С. 994 - 999

Опубликована: Янв. 30, 2024

An electroreductive cross-electrophile coupling protocol was developed for the construction of valuable 1,3-dienes from vinyl bromides. Furthermore, this scalable method can also be used to forge complex [4 + 2] cycloadducts in a one-pot manner. One most important advantages green and sustainable is situ release nickel catalyst inexpensive electrodes without addition extra harmful metal catalysts reductant.

Язык: Английский

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