Iridium-Catalyzed Asymmetric Allylic Substitution Reactions

Chemical Reviews, Год журнала: 2018, Номер 119(3), С. 1855 - 1969

Опубликована: Дек. 24, 2018

In this review, we summarize the origin and advancements of iridium-catalyzed asymmetric allylic substitution reactions during past two decades. Since first report in 1997, Ir-catalyzed have attracted intense attention due to their exceptionally high regio- enantioselectivities. been significantly developed recent years many respects, including ligand development, mechanistic understanding, substrate scope, application synthesis complex functional molecules. an explicit outline ligands, mechanism, scope nucleophiles, applications is presented.

Язык: Английский

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Ir/Cu Dual Catalysis: Enantio- and Diastereodivergent Access to α,α-Disubstituted α-Amino Acids Bearing Vicinal Stereocenters

Journal of the American Chemical Society, Год журнала: 2018, Номер 140(6), С. 2080 - 2084

Опубликована: Янв. 30, 2018

We describe a fully stereodivergent synthesis of range α,α-disubstituted α-amino acids via an Ir/Cu-catalyzed α-allylation readily available imine esters. The introduction Cu-Phox complex-activated ester into the chiral iridium-catalyzed allylic allylation process is crucial for its high reactivity and excellent enantio- diastereoselectivity (up to >99% ee >20:1 dr). Importantly, two catalysts allow full control over configuration stereocenters, affording all stereoisomers desired products. utility this methodology was demonstrated by synthesizing dipeptides analogues bioactive molecules in manner.

Язык: Английский

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2-Azaallyl Anions, 2-Azaallyl Cations, 2-Azaallyl Radicals, and Azomethine Ylides

Chemical Reviews, Год журнала: 2018, Номер 118(20), С. 10393 - 10457

Опубликована: Окт. 10, 2018

This review covers the use of 2-azaallyl anions, cations, and radicals in organic synthesis up through June 2018. Particular attention is paid to both foundational studies recent advances over past decade involving semistabilized nonstabilized anions as key intermediates various carbon–carbon carbon–heteroatom bond-forming processes. Both transition-metal-catalyzed transition-metal-free transformations are covered. Azomethine ylides, which have received significant elsewhere, discussed briefly with primary focus on critical comparisons regard generation use.

Язык: Английский

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Organo/Transition-Metal Combined Catalysis Rejuvenates Both in Asymmetric Synthesis

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(6), С. 2415 - 2437

Опубликована: Янв. 20, 2022

Since its advent two decades ago, asymmetric organo/transition-metal combined catalysis (AOMC), including cooperative and relay catalysis, has leveraged redistribution of chemical bonds to build up molecular complexity enantio-differentiation form individual enantiomers with activations from versatile organocatalysts transition-metal complexes. The goal this perspective is provide readers the fundamental attributes AOMC─orthogonality, kinetics, mechanism, selectivity─to understand how an organocatalyst a complex would collaborate enable fruitful new reaction development what are intrinsic pathways unproductive events, such as catalyst self-quenching. In closing, future opportunities AOMC have been directed toward prediction effective combination, introducing enzyme focus on transient radical intermediate, animate area in years come.

Язык: Английский

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Sequence‐Dependent Stereodivergent Allylic Alkylation/Fluorination of Acyclic Ketones

Angewandte Chemie International Edition, Год журнала: 2019, Номер 59(5), С. 2039 - 2043

Опубликована: Ноя. 6, 2019

Abstract The stereodivergent iridium‐catalyzed allylic alkylation and fluorination of acyclic ketones is described. α‐Pyridyl‐α‐fluoroketones with vicinal tertiary quaternary stereocenters were obtained in moderate to excellent yields stereoselectivities. Distinct from known synthesis, for which two different chiral catalysts are required general, herein we report a sequence‐dependent synthesis. With only single Ir catalyst, all four possible stereoisomers the products prepared same starting materials by simply adjusting sequence asymmetric varying absolute configuration catalyst.

Язык: Английский

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Cooperative N-heterocyclic Carbene and Iridium Catalysis Enables Stereoselective and Regiodivergent [3 + 2] and [3 + 3] Annulation Reactions

ACS Catalysis, Год журнала: 2021, Номер 11(7), С. 3810 - 3821

Опубликована: Март 12, 2021

A cooperative N-heterocyclic carbene (NHC)/iridium catalysis has been developed to achieve highly stereoselective and regiodivergent [3 + 2] 3] annulation reactions of 2-indolyl allyl carbonates with enals. The use the NHC catalyst introduced switchable homoenolate enolate intermediates from common enal precursor via a simple adjustment reaction conditions in predictable manner. This protocol furnishes two types biologically important products, pyrrolo[1,2-a]indoles pyridine[1,2-a]indoles, high diastereo- enantioselectivities (up >20:1 dr >99% ee). Notably, all four stereoisomers these products vicinal stereocenters could be afforded through permutations enantiomers chiral catalysts. Mechanistic investigations further computational density functional theory calculations give an explanation origin regioselectivity. In addition, NHC-enolate intermediate generated formylcyclopropanes was also compatible this catalytic system thus arsenal optically pure pyrrolo[1,2-a]indole enriched.

Язык: Английский

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Visible-Light-Mediated Carbonyl Alkylative Amination to All-Alkyl α-Tertiary Amino Acid Derivatives

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(3), С. 1598 - 1609

Опубликована: Янв. 11, 2021

The all-alkyl α-tertiary amino acid scaffold represents an important structural feature in many biologically and pharmaceutically relevant molecules. Syntheses of this class molecule, however, often involve multiple steps require activating auxiliary groups on the nitrogen atom or tailored building blocks. Here, we report a straightforward, single-step, modular methodology for synthesis esters. This new strategy uses visible light silane reductant to bring about carbonyl alkylative amination reaction that combines wide range primary amines, α-ketoesters, alkyl iodides form functionally diverse Brønsted acid-mediated situ condensation amine α-ketoester delivers corresponding ketiminium species, which undergoes rapid 1,2-addition radical (generated from iodide by action reductant) aminium cation. Upon polarity-matched irreversible hydrogen transfer electron rich silane, electrophilic cation is converted ester product. benign nature process allows broad scope all three components generates structurally suite esters will likely have widespread use academic industrial settings.

Язык: Английский

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Stereodivergent Construction of Csp³−Csp³Bonds Bearing Vicinal Stereocenters by Synergistic Palladium and Phase‐Transfer Catalysis

Angewandte Chemie International Edition, Год журнала: 2022, Номер 62(2)

Опубликована: Ноя. 16, 2022

Abstract Synergistic catalysis has emerged as one of the most powerful tools for stereodivergent formation Csp 3 −Csp bonds bearing vicinal stereocenters. Despite many successes that have been achieved in this field, coupling reactions involving stabilized nucleophiles remain challenging because competing single‐catalysis pathway. Herein, we report a synergistic palladium/phase‐transfer catalyst system enables diastereodivergent 1,3‐dienes with nucleophile oxindoles. Both syn and anti products, quaternary tertiary stereocenters, could be selectively produced good yields high enantio‐ diastereoselectivities. Non‐covalent activation via chiral ion pair biphasic is crucial success factor achieving diastereodivergence.

Язык: Английский

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Catalyst‐Controlled Regiodivergent and Enantioselective Formal Hydroamination of N,N‐Disubstituted Acrylamides to α‐Tertiary‐α‐Aminolactam and β‐Aminoamide Derivatives

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(22)

Опубликована: Март 30, 2023

Enantioenriched α-tertiary-α-aminoacid and α-chiral-β-aminoacid derivatives play an important role in biological science pharmaceutical chemistry. Thus, the development of methods for their synthesis is highly valuable yet remains challenging. Herein, unprecedented catalyst-controlled regiodivergent enantioselective formal hydroamination N,N-disubstituted acrylamides with aminating agents has been developed, accessing enantioenriched α-tertiary-α-aminolactam α-chiral-β-aminoamide derivatives. Sterically-disfavored electronically-disfavored electron-deficient alkenes have successfully tuned using different transition metals chiral ligands. Notably, extremely hindered aliphatic were synthesized by Cu-H catalyzed asymmetric C-N bond forming tertiary alkyl species. accessed Ni-H anti-Markovnikov-selective hydroaminations alkenes. This set reactions tolerates a wide range functional groups to deliver diverse good yields high levels enantioselectivity.

Язык: Английский

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Catalytic Asymmetric Synthesis of Trifluoromethylated γ‐Amino Acids through the Umpolung Addition of Trifluoromethyl Imines to Carboxylic Acid Derivatives

Angewandte Chemie International Edition, Год журнала: 2017, Номер 57(8), С. 2233 - 2237

Опубликована: Дек. 12, 2017

Abstract Novel cinchona alkaloid derived chiral phase‐transfer catalysts enabled the highly chemo‐, regio‐, diastereo‐, and enantioselective umpolung addition of trifluoromethyl imines to α,β‐unsaturated N ‐acyl pyrroles. With a catalyst loading ranging from 0.2 5.0 mol %, this new catalytic asymmetric transformation provides facile high‐yielding access enantiomerically enriched trifluoromethylated γ‐amino acids γ‐lactams.

Язык: Английский

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