Recent Advances in Enantioselective Pd-Catalyzed Allylic Substitution: From Design to Applications

Chemical Reviews, Год журнала: 2021, Номер 121(8), С. 4373 - 4505

Опубликована: Март 19, 2021

This Review compiles the evolution, mechanistic understanding, and more recent advances in enantioselective Pd-catalyzed allylic substitution decarboxylative oxidative substitutions. For each reaction, catalytic data, as well examples of their application to synthesis complex molecules, are collected. Sections which we discuss key aspects for high selectivity a comparison with other metals (with advantages disadvantages) also included. asymmetric substitution, data grouped according type nucleophile employed. Because prominent position use stabilized carbon nucleophiles heteronucleophiles, many chiral ligands have been developed. To better compare results, they presented by ligand types. reactions mainly promoted PHOX or Trost ligands, justifies organizing this section chronological order. results used.

Язык: Английский

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Enantioselective Formation of Quaternary Centers by Allylic Alkylation with First-Row Transition-Metal Catalysts

Chemical Reviews, Год журнала: 2021, Номер 121(7), С. 4084 - 4099

Опубликована: Фев. 11, 2021

Asymmetric allylic alkylation mediated by transition metals provides an efficient strategy to form quaternary stereogenic centers. While this transformation is dominated the use of second- and third-row (e.g., Pd, Rh, Ir), recent developments have revealed potential first-row metals, which provide not only a less expensive potentially equally alternative but also new mechanistic possibilities. This review summarizes examples for assembly stereocenters using prochiral substrates hard, achiral nucleophiles in presence copper complexes highlights complementary approaches with soft, catalyzed chiral cobalt nickel complexes.

Язык: 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, Год журнала: 2024, Номер 63(7)

Опубликована: Янв. 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.

Язык: Английский

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Cobalt-Catalyzed Diastereo- and Enantioselective Reductive Allyl Additions to Aldehydes with Allylic Alcohol Derivatives via Allyl Radical Intermediates

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(32), С. 12755 - 12765

Опубликована: Авг. 5, 2021

Catalytic generation of ambiphilic π-allyl–metal complexes and their utility in enantioselective transformations constitutes a powerful approach for introduction allyl groups to molecule. Herein an unprecedented cobalt-catalyzed highly site-, diastereo-, protocol stereoselective formation nucleophilic allyl–Co(II) followed by addition aldehydes is presented. The reaction features diastereo- enantioconvergent conversion easily accessible allylic alcohol derivatives diversified enantioenriched homoallylic alcohols with remarkably broad scope that can be introduced. Mechanistic studies indicated radical intermediates were involved this process. These new discoveries establish strategy development through capture radicals chiral Co complexes, pushing forward the frontier catalysis.

Язык: Английский

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Rh-Catalyzed Regio- and Enantioselective Allylic Phosphinylation

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(7), С. 2893 - 2898

Опубликована: Фев. 14, 2022

Transition-metal-catalyzed branched and enantioselective allylic substitution of monosubstituted precursors with carbon, nitrogen, oxygen, sulfur, fluoride nucleophiles has been well-established. However, such a selective carbon–phosphorus bond formation not realized probably due to the catalyst deactivation by strong coordinating nature phosphinylating reagents. Herein, we report Rh-catalyzed highly regio- synthesis phosphine oxides in presence chiral bisoxazoline-phosphine ligand. The application α-hydroxylalkylphosphine keep low concentration secondary is essential for high yields. addition diphenyl phosphoric acid was found only activate alcohols but also accelerate formation.

Язык: Английский

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Regio- and Stereoselective Reductive Coupling of Alkynes and Crotononitrile

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(50), С. 23001 - 23009

Опубликована: Дек. 8, 2022

A new regio- and stereoselective reductive coupling of alkynes crotononitrile has been developed via visible light organophotoredox cobalt dual catalysis. variety enantioenriched homoallylic nitriles bearing a stereodefined trisubstituted alkene have easily synthesized with good to excellent (up >20:1 rr), stereo- (>20:1 E/Z), enantioselectivity 98% ee) control under mild conditions. The corresponding nitrile products were smoothly converted into various chiral building blocks. Remarkably, simple organic base together water utilized as hydrogen sources in this photoinduced reaction.

Язык: Английский

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Regio- and Enantioselective Allylic Cyanomethylation by Synergistic Rhodium and Silane Catalysis

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(7), С. 3897 - 3902

Опубликована: Фев. 8, 2023

Rh/silane-cocatalyzed regio- and enantioselctive allylic cyanomethylation with inert acetonitrile directly has been developed. Addition of a catalytic amount neutral silane reagent as an anion carrier is essential for the success this reaction. The synthesis mono- bis-allylation products can be switched by adjusting size substituents on silane, ligands, temperature. Chiral homoallylic nitriles could synthesized in above 20:1 branch/linear ratio, up to 98% yield >99% ee.

Язык: 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, Год журнала: 2024, Номер 63(25)

Опубликована: Янв. 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.

Язык: Английский

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Enantioselective Synthesis of Pyridines with All‐Carbon Quaternary Carbon Centers via Cobalt‐Catalyzed Desymmetric [2+2+2] Cycloaddition

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(37), С. 20204 - 20209

Опубликована: Июль 2, 2021

Abstract A Co‐catalyzed enantioselective desymmetric [2+2+2] cycloaddition for synthesis of pyridines with all‐carbon quaternary carbon centers has been developed. The regio‐ and enantioselectivities are controlled by the inherent nature terminal alkynes substituents on bisoxazolinephosphine ligands. Pyridines 5‐substitutents could be obtained >20:1 regioselectivity up to 94 % ee when alkyl, alkenyl or silyl DTBM/Ph‐based NPN* ligand L6 were used. Terminal aryl Ph/Bn‐based L4 leads formation 6‐substitutents in 99 .

Язык: Английский

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Rhodium-Catalyzed Regio- and Enantioselective Allylic Amination of Racemic 1,2-Disubstituted Allylic Phosphates

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(22), С. 8255 - 8260

Опубликована: Май 24, 2021

Alkynylphosphines are rarely used as ligands in asymmetric metal catalysis. We synthesized a series of chiral bis(oxazoline)alkynylphosphine and them Rh-catalyzed highly regio- enantioselective allylic amination reactions 1,2-disubstituted phosphates. Chiral amines were up to 95% yield with >20:1 branched/linear (b/l) ratio 99% ee from racemic precursors. The sterically smaller linear alkynyl group on the P atom was key fit new requirements introduction bulky 2-R' groups.

Язык: Английский

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