P-Stereogenic Phosphorus Ligands in Asymmetric Catalysis

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(14), P. 8657 - 8739

Published: July 2, 2024

Chiral phosphorus ligands play a crucial role in asymmetric catalysis for the efficient synthesis of useful optically active compounds. They are largely categorized into two classes: backbone chirality and P-stereogenic ligands. Most reported belong to former class. Privileged ones such as BINAP DuPhos frequently employed wide range catalytic transformations. In contrast, latter class has remained small family many years mainly because their synthetic difficulty. The late 1990s saw emergence novel with superior enantioinduction ability Rh-catalyzed hydrogenation reactions. Since then, numerous have been synthesized used This Review summarizes thus far, including stereochemical electronic properties that afford high excellent enantioselectivities. Examples reactions use this described together applications construction key intermediates natural products therapeutic agents. literature covered dates back 1968 up until December 2023, centering on studies published later years.

Language: Английский

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Cobalt‐Catalyzed Asymmetric Aza‐Nozaki–Hiyama–Kishi (NHK) Reaction of α‐Imino Esters with Alkenyl Halides

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(7)

Published: Jan. 2, 2024

Chromium-catalyzed enantioselective Nozaki-Hiyama-Kishi (NHK) reaction represents one of the most powerful approaches for formation chiral carbon-heteroatom bond. However, construction sterically encumbered tetrasubstituted stereocenter through NHK still posts a significant challenge. Herein, we disclose cobalt-catalyzed aza-NHK ketimine with alkenyl halide to provide convenient synthetic approach manufacture enantioenriched α-vinylic amino acid. This protocol exhibits excellent functional group tolerance 99 % ee in cases. Additionally, this asymmetric reductive method is also applicable aldimine access trisubstituted stereogenic centers.

Language: Английский

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Desymmetrization–Addition Reaction of Cyclopropenes to Imines via Synergistic Photoredox and Cobalt Catalysis

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(28), P. 18892 - 18898

Published: July 5, 2024

Herein, we designed a reaction for the desymmetrization-addition of cyclopropenes to imines by leveraging synergy between photoredox and asymmetric cobalt catalysis. This protocol facilitated synthesis series chiral functionalized cyclopropanes with high yield, enantioselectivity, diastereoselectivity (44 examples, up 93% yield >99% ee). A possible mechanism involving cyclopropene desymmetrization Co-H species imine addition Co-alkyl was proposed. study provides novel route important extends frontier metallaphotoredox

Language: Английский

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Nickel-Catalyzed Enantioselective Reductive Arylation and Heteroarylation of Aldimines via an Elementary 1,4-Addition

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(15), P. 8498 - 8509

Published: April 6, 2023

Nickel catalysts of chiral pyrox ligands promoted enantioselective reductive arylation and heteroarylation aldimines, using directly (hetero)aryl halides sulfonates. The catalytic can also be conducted with crude aldimines generated from condensation aldehydes azaaryl amines. Mechanistically, density functional theory (DFT) calculations experiments pointed to an elementary step 1,4-addition aryl nickel(I) complexes N-azaaryl aldimines.

Language: Английский

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Cobalt‐Catalyzed Enantioselective Reductive α‐Chloro‐Carbonyl Addition of Ketimine to Construct the β‐Tertiary Amino Acid Analogues

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(25)

Published: Jan. 22, 2024

β-Tertiary amino acid derivatives constitute one of the most frequently occurring units in natural products and bioactive molecules. However, efficient asymmetric synthesis this motif still remains a significant challenge. Herein, we disclose cobalt-catalyzed enantioselective reductive addition reaction ketimine using α-chloro carbonyl compound as radical precursor, providing expedient access to diverse array enantioenriched β-quaternary analogues. This protocol exhibits outstanding enantioselectivity broad substrate scope with excellent functional group tolerance. Preliminary mechanism studies rule out possibility Reformatsky-type confirm involvement species stereoselective process. The synthetic utility has been demonstrated through rapid assembly iterative oligopeptide, showcasing its versatile platform for late-stage modification drug candidates.

Language: Английский

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Nickel-Catalyzed Enantioselective Reductive Arylation of Common Ketones

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(19), P. 12895 - 12900

Published: May 2, 2024

A nickel complex of chiral bisoxazolines catalyzed the stereoselective reductive arylation ketones in high enantioselectivity. range common acyclic and cyclic reacted without aid directing groups. Mechanistic studies using isolated a bis(oxazoline) (L)Ni(Ar)Br revealed that Mn reduction was not needed, while Lewis acidic titanium alkoxides were critical to ketone insertion.

Language: Английский

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Cobalt-Catalyzed Asymmetric Reductive Alkenylation and Arylation of Heterobiaryl Tosylates: Kinetic Resolution or Dynamic Kinetic Resolution?

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(49), P. 26747 - 26755

Published: Nov. 29, 2023

Herein, we report a cobalt-catalyzed atroposelective reductive cross-coupling of racemic heterobiaryl tosylates with C(sp2)–X type electrophile. Both aryl and alkenyl halides are competent precursors for this reaction, providing variety heterobiaryls as the products in highly enantioselective manner high functionality tolerance. The related asymmetric arylation alkenylation discovered to proceed divergent mechanisms. reaction pathway changes from kinetic resolution (KR) when bromides iodides bearing strong electron-withdrawing substitution on para-position employed starting materials an enantioconvergent transformation via dynamic KR configurationally labile cobaltacycles relatively electron-rich used. change mechanisms turns out arise relative rates two competing elementary steps, which epimerization cyclic Co(I) intermediates their trapping by coupling electrophiles C(sp2)-type oxidative addition.

Language: Английский

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Chromium‐ and Metal‐Reductant‐Free Asymmetric Nozaki–Hiyama–Kishi (NHK) Reaction Enabled by Metallaphotoredox Catalysis

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(37)

Published: June 25, 2024

Abstract Chiral allylic alcohols are highly prized in synthetic chemistry due to their versatile reactivity stemming from both alkenyl and hydroxyl functionalities. While the Nozaki–Hiyama–Kishi (NHK) reaction is a widely used method for synthesis of alcohols, it suffers drawbacks such as use toxic chromium salts, high amounts metal reductants, poor enantiocontrol. To address these limitations, we present novel approach involving metallaphotoredox‐catalyzed asymmetric NHK production chiral alcohols. This marries (pseudo)halides with aldehydes, leveraging synergistic blend nickel catalyst photocatalyst. innovative technique enables oxidative addition insertion just using nickel, diverging significantly conventional pathway mediated by salts. The adoption this methodology holds immense promise crafting spectrum intricate compounds, particularly those significance pharmaceuticals. Detailed experimental investigations have shed light on metallaphotoredox process, further enhancing our understanding enabling advancements.

Language: Английский

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Strategies for Carbon Electrophile Addition to Carbonyls and Imines by Cobalt Catalysis

European Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 26(45)

Published: Oct. 16, 2023

Abstract The addition of carbon electrophiles to carbonyls and imines has emerged as a valuable strategy for the construction C−C bonds. merger this concept with sustainable cobalt catalysis yielded numerous innovative methodologies. Remarkable functional group tolerance selectivity have been observed in many cases, providing reliable methods bond construction. cobalt‐catalyzed additions carbonyls, carboxylic acid derivatives described review include earliest reports, such Takai‐Utimoto Co/Cr co‐catalyzed their progression, well modern variants, exemplified by recent Co/photoredox protocols. systematic appraisal provides clearer perspective inspiration its further development.

Language: Английский

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Cobalt-Catalyzed Enantioselective Reductive Arylation, Heteroarylation, and Alkenylation of Michael Acceptors via an Elementary Mechanism of 1,4-Addition

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(29), P. 20477 - 20493

Published: July 10, 2024

Cobalt complexes with chiral quinox ligands effectively promote the enantioselective conjugate addition of enones using aryl, heteroaryl, and alkenyl halides sulfonates. Additionally, a cobalt complex strongly donating diphosphine, BenzP*, successfully catalyzes asymmetric reductive arylation alkenylation α,β-unsaturated amides. Both catalytic systems show broad scopes tolerance sensitive functional groups. reactions can be scaled up low loadings catalysts. Experimental results density theory (DFT) calculations suggest new mechanism elementary 1,4-addition aryl cobalt(I) complexes.

Language: Английский

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