Nickel-Catalyzed Enantioselective Reductive Cross-Coupling Reactions

ACS Catalysis, Journal Year: 2020, Volume and Issue: 10(15), P. 8237 - 8246

Published: June 24, 2020

Nickel-catalyzed reductive cross-coupling reactions have emerged as powerful methods to join two electrophiles. These proven particularly useful for the coupling of sec-alkyl electrophiles form stereogenic centers; however, development enantioselective variants remains challenging. In this Perspective, we summarize progress that has been made toward Ni-catalyzed reactions.

Language: Английский

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Mechanisms of Nickel-Catalyzed Cross-Coupling Reactions

Trends in Chemistry, Journal Year: 2019, Volume and Issue: 1(9), P. 830 - 844

Published: Sept. 13, 2019

Language: Английский

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Nickel-Catalyzed Dicarbofunctionalization of Alkenes

ACS Catalysis, Journal Year: 2020, Volume and Issue: 10(15), P. 8542 - 8556

Published: July 2, 2020

1,2-Dicarbofunctionalization of alkenes has emerged as an efficient synthetic strategy for preparing substituted molecules by coupling readily available with electrophiles and/or nucleophiles. Nickel complexes serve effective catalysts owing to their tendency undergo facile oxidative addition and slow β-hydride elimination, capability access both two-electron radical pathways. Two-component alkene functionalization reactions have achieved high chemo-, regio-, stereoselectivities tethering one the partners substrate. Three-component reactions, however, often incorporate directing groups control selectivity. Only a few examples directing-group-free difunctionalizations unactivated been reported. Therefore, great opportunities exist development three-component difunctionalization broad substrate scopes tunable stereoselectivities.

Language: Английский

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Mechanisms of Nickel-Catalyzed Coupling Reactions and Applications in Alkene Functionalization

Accounts of Chemical Research, Journal Year: 2020, Volume and Issue: 53(4), P. 906 - 919

Published: April 2, 2020

ConspectusNickel complexes exhibit distinct properties from other group 10 metals, including a small nuclear radius, high paring energy, low electronegativity, and redox potentials. These enable Ni catalysts to accommodate stabilize paramagnetic intermediates, access radical pathways, undergo slow β-H elimination. Our research program investigates how each of these fundamental attributes impact the catalytic Ni, in particular context alkene functionalization.Alkenes are versatile functional groups, but stereoselective carbofunctionalization reactions alkenes have been underdeveloped. This challenge may derive difficulty controlling selectivity via traditional two-electron migratory insertion pathways. could lead different stereodetermining steps mechanisms, allowing molecular scaffolds that otherwise difficult prepare. For example, an asymmetric diarylation reaction developed by our relies upon Ni(III) intermediates control enantioselectivity give library chiral α,α,β-triarylethane molecules with biological activity.Mechanistic studies on two-component reductive 1,2-difunctionalization shed light origin cross-electrophile selectivity, as C sp2 sp3 electrophiles independently activated at Ni(I) respectively. Catalyst reduction has identified be turnover-limiting step this system. A closer investigation formation using (Xantphos)Ni(I)Ar model complex reveals initiates concerted halogen-abstraction pathway.The potentials allowed us develop reductive, trans-selective diene cyclization, wherein classic mechanism operates Ni(I)/Ni(III) platform, accounting for chemo- stereoselectivity. found applications efficient synthesis pharmaceutically relevant molecules, such 3,4-dimethylgababutin.The tendency one-electron processes prompted explore dinuclear Ni-mediated bond formations. provide insight into Ni–Ni bonding two metal centers react cooperatively promote C–C, C–X, N–N forming elimination.Finally, isolation β-agostic Pd X-ray neutron diffraction characterization highly reactive molecules. The parameters serve unambiguous evidence interactions help rationalize slower elimination relative Pd. Overall, elucidated several contexts. Greater mechanistic understanding facilitates catalyst design helps reactivity Ni-catalyzed functionalization reactions.

Language: Английский

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Cross-Electrophile Couplings of Activated and Sterically Hindered Halides and Alcohol Derivatives

Accounts of Chemical Research, Journal Year: 2020, Volume and Issue: 53(9), P. 1833 - 1845

Published: Aug. 25, 2020

ConspectusTransition metal catalyzed cross-electrophile coupling of alkyl electrophiles has evolved into a privileged strategy that permits the facile construction valuable C(sp3)–C bonds. Numerous elegant Ni-catalyzed methods, for example, arylation, allylation, acylation, and vinylation primary secondary halides have been developed. This prior work provided important mechanistic insights selectivity reactivity partners, which are largely dictated by both catalysts reactants. In spite advances made to date, number challenging issues remain, including (1) achieving stereoselective syntheses C–C bonds rely primarily on functionalized or activated precursors, (2) diversifying electrophiles, (3) gaining underlying reaction mechanisms.In this Account, we summarize Ni- Fe-catalyzed reductive bond forming methods developed in our laboratory, allowed us couple activated, sterically hindered tertiary C(sp3)–O access methylated trifluoromethylated products, esters, C-glycosides, quaternary carbon centers. We will begin with brief discussion chemoselective unactivated alkyl–alkyl bonds, focus effects ligands reductants, along leaving group-directed reactivities halides, role they play promoting methyl, trifluoromethyl, glycosyl chloroformates. Matching these suitable partners is considered essential success; something can be tuned means appropriate Ni catalysts. Second, detail how tuning steric electronic nickel labile pyridine-type additives (primarily MgCl2) effective creation arylated all-carbon centers through aryl encumbered halides. contrast, use bulkier bipyridine terpyridine incorporation relative small-sized acyl allyl groups acylated allylated Finally, show knowledge gained halide enabled develop permit oxalates allyl, aryl, vinyl wherein Barton C–O radical fragmentation mediated Zn MgCl2 promoted The same protocol applicable arylation derived from α-hydroxyl carbonyl substrates, involves formation relatively stable α-carbonyl centered radicals. Thus, Account not only summarizes synthetic allow using but also provides insight relationship between structure substrates catalysts, as well additives.

Language: Английский

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Enantioselective Three-Component Fluoroalkylarylation of Unactivated Olefins through Nickel-Catalyzed Cross-Electrophile Coupling

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(21), P. 9604 - 9611

Published: May 11, 2020

A nickel-catalyzed, enantioselective, three-component fluoroalkylarylation of unactivated alkenes with aryl halides and perfluoroalkyl iodides has been described. This cross-electrophile coupling protocol utilizes a chiral nickel/BiOx system as well pendant chelating group to facilitate the challenging three-component, asymmetric difunctionalization alkenes, providing direct access valuable β-fluoroalkyl arylalkanes high efficiency excellent enantioselectivity. The mild conditions allow for broad substrate scope good functional toleration.

Language: Английский

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A Brief Introduction to Chemical Reaction Optimization

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(6), P. 3089 - 3126

Published: Feb. 23, 2023

From the start of a synthetic chemist's training, experiments are conducted based on recipes from textbooks and manuscripts that achieve clean reaction outcomes, allowing scientist to develop practical skills some chemical intuition. This procedure is often kept long into researcher's career, as new developed similar protocols, intuition-guided deviations through learning failed experiments. However, when attempting understand systems interest, it has been shown model-based, algorithm-based, miniaturized high-throughput techniques outperform human intuition optimization in much more time- material-efficient manner; this covered detail paper. As many chemists not exposed these undergraduate teaching, leads disproportionate number scientists wish optimize their reactions but unable use methodologies or simply unaware existence. review highlights basics, cutting-edge, modern well its relation process scale-up can thereby serve reference for inspired each techniques, detailing several respective applications.

Language: Английский

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Nickel/Photo-Cocatalyzed Asymmetric Acyl-Carbamoylation of Alkenes

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(5), P. 2180 - 2186

Published: Jan. 23, 2020

An unprecedented asymmetric acyl-carbamoylation of pendant alkenes tethered on aryl carbamic chlorides with both aliphatic and aromatic aldehydes has been developed via the cooperative catalysis a chiral nickel-PHOX complex tetrabutylammonium decatungstate. This reaction represents first example merging hydrogen-atom-transfer photochemistry transition metal in difunctionalization alkenes. Using this protocol, variety oxindoles bearing challenging quaternary stereogenic center are furnished under mild conditions highly enantioselective manner.

Language: Английский

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Cross-Electrophile Coupling of Unactivated Alkyl Chlorides

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(27), P. 11691 - 11697

Published: June 20, 2020

Alkyl chlorides are bench-stable chemical feedstocks that remain among the most underutilized electrophile classes in transition metal catalysis. Overcoming intrinsic limitations of C(sp3)–Cl bond activation, we report development a novel organosilane reagent can participate chlorine atom abstraction under mild photocatalytic conditions. In particular, describe application this mechanism to dual nickel/photoredox catalytic protocol enables first cross-electrophile coupling unactivated alkyl and aryl chlorides. Employing these low-toxicity, abundant, commercially available organochloride building blocks, methodology allows access broad array highly functionalized C(sp2)–C(sp3) coupled adducts, including numerous drug analogues.

Language: Английский

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Nickel‐CatalyzedDicarbofunctionalization of Alkenes^†

Chinese Journal of Chemistry, Journal Year: 2020, Volume and Issue: 38(11), P. 1371 - 1394

Published: June 16, 2020

As a straightforward strategy for rapidly increasing molecular complexity, dicarbofunctionalization of alkenes has attracted substantial interests organic synthesis, medicine chemistry, and materials science. Nickel‐catalyzed cascade dicarbofunctionalizations have been flourished in this area recently, nickel‐mediated radical pathways particularly offer new opportunities conjunctive cross‐couplings with alkyl coupling partners. Herein, we give comprehensive review nickel‐catalyzed through historical perspective, including intermolecular three‐component reactions intramolecular reactions. Among the discussed review, carbometallation/cross‐coupling process addition/cross‐coupling are two major alkenes. The oxidative cyclization 1,2‐metallate shift processes also selectively discussed. These methods overcome limitations associated using noble metals field, providing an efficient access to structurally diversified molecules.

Language: Английский

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