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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Expedient Synthesis of Axially and Centrally Chiral Diaryl Ethers via Cobalt-Catalyzed Photoreductive Desymmetrization

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(7), P. 4638 - 4647

Published: March 12, 2024

Axially chiral diaryl ethers make up a unique class of atropisomers bearing restricted rotation about the C–O bond. Methods for expedient synthesis axially ether-based structures have been largely underdeveloped. Herein, we developed an efficient metal-catalyzed desymmetrization strategy to unveil formation and centrally dual in high diastereo- enantioselectivity. The protocol leverages cobalt-catalyzed photoreductive enantioselective couplings dialdehyde alkyne deliver stereogenicity, ether scaffold is equipped with useful synthetic handles including formyl, hydroxyl, allyl groups, as has demonstrated carboxylic acid potential ligand asymmetric catalysis.

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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Bis(diiminate)-Supported Bimetallic Complexes: Tri-Coordinated Zinc for Nitrile and Carbodiimide Hydroboration

ACS Omega, Journal Year: 2025, Volume and Issue: 10(2), P. 2033 - 2043

Published: Jan. 10, 2025

We report the synthesis and characterization of bis(diiminate)-supported tricoordinated zinc complexes (1–4) demonstrate catalytic activity one representative compound in hydroboration nitriles carbodiimides using pinacolborane (HBpin). Experimental theoretical studies were performed to elucidate reaction mechanism. Our findings indicate that initiates with formation a hydride intermediate, followed by subsequent attack carbodiimides. This leads four-membered metallacycle before release diborylated amine. work provides access new types highlights its effectiveness carbodiimides, offering milder alternative existing reduction methods.

Language: Английский

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Pathway-divergent coupling of 1,3-enynes with acrylates through cascade cobalt catalysis

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: April 23, 2024

Catalytic cascade transformations of simple starting materials into highly functionalized molecules bearing a stereochemically defined multisubstituted alkene, which are important in medicinal chemistry, natural product synthesis, and material science, high demand for organic synthesis. The development multiple reaction pathways accurately controlled by catalysts derived from different ligands is critical goal the field catalysis. Here we report cobalt-catalyzed strategy direct coupling inexpensive 1,3-enynes with two acrylates to construct diversity 1,3-dienes containing trisubstituted or tetrasubstituted olefin. Such reactions can proceed through three initiated oxidative cyclization achieve bond formation chemo-, regio- stereoselectivity precisely ligands, providing platform tandem carbon-carbon bond-forming reactions.

Language: Английский

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Regio‐ and enantioselective nickel-alkyl catalyzed hydroalkylation of alkynes

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Aug. 2, 2024

Abstract The migratory insertion of metal-hydride into alkene has allowed regioselective access to organometallics, readily participating in subsequent functionalization as one conventional pathway hydroalkylation, whereas analogous process with feedstock alkyne is drastically less explored. Among few examples, the regioselectivity mostly governed by electronic bias alkynes. To alter and expand intermediate pools that we can access, aspirational design through alternative nickel-alkyl insertion, providing opposite induced steric demand. Leveraging situ formed species, herein report regio- enantioselective hydroalkylation alkynes broad functional group tolerance, excellent enantioselectivity, enabling efficient route diverse valuable chiral allylic amines motifs. Preliminary mechanistic studies indicate aminoalkyl radical species participate metal-capture lead formation nickel-alkyl, which key reverse observed insertion.

Language: Английский

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A General Enantioselective α-Alkyl Amino Acid Derivatives Synthesis Enabled by Cobalt-Catalyzed Reductive Addition

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 12, 2024

Enantioenriched unnatural amino acids represent a prevalent motif in organic chemistry, with profound applications biochemistry, medicinal and materials science. Herein, we report cobalt-catalyzed aza-Barbier reaction of dehydroglycines unactivated alkyl halides to afford α-amino esters high enantioselectivity. This catalytic reductive alkylative addition protocol circumvents the use moisture-, air-sensitive organometallic reagents, stoichiometric chiral auxiliaries, enabling conversion variety primary, secondary, even tertiary α-alkyl-amino under mild conditions, thus leading broad functional group tolerance. The expedient access biologically active motifs demonstrates practicality this by reducing number synthetic steps enhancing efficiency.

Language: Английский

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Catalytic Asymmetric Barbier Reaction of Ketones with Unactivated Alkyl Electrophiles

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 3, 2024

The Barbier reaction is a reductive-type addition of an aldehyde or ketone with organic electrophile in the presence terminal metal reductant, providing straightforward and efficient method for carbon-carbon bond formation. This possesses advantage circumventing preparation moisture- air-sensitive organometallic reagents. However, catalytic ketones to construct tetrasubstituted stereogenic centers largely underdeveloped, despite its great potential accessing synthetically challenging chiral tertiary alcohol. Particularly, leveraging unactivated alkyl electrophiles as coupling components still rarely exploited. Herein, we disclose photoredox-assisted cobalt-catalyzed asymmetric alkylative Barbier-type address aforementioned challenges, thereby allowing construction highly congested carbon centers. fragments could be either readily accessible halides redox-active esters generated through decarboxylative pathway. Both types include primary, secondary, ones, thus affording diverse enantioenriched alcohols broad substrate scope. enantioselective protocol applied expedient synthesis core structure

Language: Английский

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

Angewandte Chemie, Journal Year: 2024, Volume and Issue: 136(7)

Published: Jan. 2, 2024

Abstract 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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Enhanced Co‐adsorption of Alcohols and Amines for Visible Light Driven Oxidative Condensation Using Iron‐based MOF

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(43)

Published: May 28, 2024

Imines are essential intermediates in organic transformations, and is generally produced by dehydrogenative condensation of alcohols amines with the assist specialized catalysts additives. Heterogeneous photocatalysis provides a sustainable platform for such process without using toxic oxidants, yet functionalized photocatalyst optimized co-adsorption reactants needs to be developed promote stoichiometric oxidative under ambient conditions. Here, we show that benzyl alcohol aniline adsorb non-interferingly on Fe node linker sites MIL-53(Fe) metal frameworks (MOFs), respectively. The both barely influences reduction molecular oxygen generate radicals, resulting efficient formation benzaldehyde visible light. Additionally, weak adsorption water together surface acidity rapid depletion generated water, achieving an C-N bond creation wide range substrates.

Language: Английский

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