Enantioselective C−H Activation with Earth‐Abundant 3d Transition Metals

Angewandte Chemie International Edition, Год журнала: 2019, Номер 58(37), С. 12803 - 12818

Опубликована: Май 11, 2019

Molecular syntheses largely rely on time- and labour-intensive prefunctionalization strategies. In contrast, C-H activation represents an increasingly powerful approach that avoids lengthy of prefunctionalized substrates, with great potential for drug discovery, the pharmaceutical industry, material sciences, crop protection, among others. The enantioselective functionalization omnipresent bonds has emerged as a transformative tool step- atom-economical generation chiral molecular complexity. However, this rapidly growing research area remains dominated by noble transition metals, prominently featuring toxic palladium, iridium rhodium catalysts. Indeed, despite significant achievements, use inexpensive sustainable 3d metals in asymmetric activations is still clearly its infancy. Herein, we discuss remarkable recent progress transformations via organometallic base up to April 2019.

Язык: Английский

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Photoinduced Remote Functionalization of Amides and Amines Using Electrophilic Nitrogen Radicals

Angewandte Chemie International Edition, Год журнала: 2018, Номер 57(39), С. 12945 - 12949

Опубликована: Авг. 7, 2018

Abstract The selective functionalization of C(sp 3 )−H bonds at distal positions to functional groups is a challenging task in synthetic chemistry. Reported here photoinduced radical cascade strategy for the divergent amides and protected amines. process based on oxidative generation electrophilic amidyl radicals their subsequent transposition by 1,5‐H‐atom transfer, resulting remote fluorination, chlorination and, first time, thioetherification, cyanation, alkynylation. tolerant most common delivers useful building blocks that can be further elaborated. utility this demonstrated through late‐stage amino acids dipeptide.

Язык: Английский

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Enantioselective Cobalt(III)‐Catalyzed C−H Activation Enabled by Chiral Carboxylic Acid Cooperation

Angewandte Chemie International Edition, Год журнала: 2018, Номер 57(47), С. 15425 - 15429

Опубликована: Окт. 6, 2018

The enantioselective cobalt(III)-catalyzed C-H alkylation was achieved through the design of a novel chiral acid. activation characterized by high position-, regio- and enantio-control under exceedingly mild reaction conditions. Thereby, robust cooperative cobalt(III) catalysis proved tolerant valuable electrophilic functional groups, including hydroxyl, bromo, iodo substituents. Mechanistic studies revealed considerable additive effect on kinetics negative non-linear-effect.

Язык: Английский

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Visible‐Light‐Enabled Ruthenium‐Catalyzed meta‐C−H Alkylation at Room Temperature

Angewandte Chemie International Edition, Год журнала: 2019, Номер 58(29), С. 9820 - 9825

Опубликована: Май 10, 2019

Visible-light-induced ruthenium catalysis has enabled remote C-H alkylations with excellent levels of position control under exceedingly mild conditions at room temperature. The metallaphotocatalysis occurred exogenous-photosensitizer-free and features an ample substrate scope. robust nature the photo-induced meta-C-H functionalization is reflected by broad functional group tolerance, reaction can be carried out in operationally simple manner, setting stage for challenging secondary tertiary ruthenaphotoredox catalysis.

Язык: Английский

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The Dual Role of Benzophenone in Visible‐Light/Nickel Photoredox‐Catalyzed C−H Arylations: Hydrogen‐Atom Transfer and Energy Transfer

Angewandte Chemie International Edition, Год журнала: 2019, Номер 58(11), С. 3566 - 3570

Опубликована: Фев. 18, 2019

A dual catalytic protocol for the direct arylation of non-activated C(sp3 )-H bonds has been developed. Upon photochemical excitation, excited triplet state a diaryl ketone photosensitizer abstracts hydrogen atom from an aliphatic C-H bond. This inherent reactivity was exploited generation benzylic radicals which subsequently enter nickel cycle, accomplishing arylation.

Язык: Английский

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Site‐Selective Remote Radical C−H Functionalization of Unactivated C−H Bonds in Amides Using Sulfone Reagents

Angewandte Chemie International Edition, Год журнала: 2018, Номер 57(39), С. 12940 - 12944

Опубликована: Авг. 7, 2018

A general and practical strategy for remote site-selective functionalization of unactivated aliphatic C-H bonds in various amides by radical chemistry is introduced. bond achieved using the readily installed N-allylsulfonyl moiety as an N-radical precursor. The situ generated engages intramolecular 1,5-hydrogen atom transfer to generate a translocated C which subsequently trapped with sulfone reagents afford corresponding functionalized amides. generality approach documented successful C-N3 , C-Cl, C-Br, C-SCF3 C-SPh, C-C formation. Unactivated tertiary secondary bonds, well activated primary can be this method.

Язык: Английский

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Recent Progress on Cyclic Nitrenoid Precursors in Transition‐Metal‐Catalyzed Nitrene‐Transfer Reactions

Chemistry - A European Journal, Год журнала: 2018, Номер 25(13), С. 3156 - 3180

Опубликована: Сен. 5, 2018

Abstract Nitrene‐transfer reactions are powerful synthetic tools for the direct incorporation of nitrogen atoms into organic molecules. The discovery novel nitrene‐transfer has been dominantly supported not only by improvements in transition‐metal catalysts but also employment precursors nitrenoids. Since pioneering work involving use azides and iminoiodinanes as practical nitrogen‐containing compounds was reported, a new approach using various N‐heterocycles containing strain energy or weak bond emerged. In this review, we briefly summarize history chemistry from viewpoint its precursors. particular, such 2 H ‐azirines, 1,4,2‐dioxazol‐5‐ones, 1,2,4‐oxadiazol‐5‐ones, isoxazol‐5(4 )‐ones, isoxazoles is comprehensively described, showing recent remarkable progress chemistry.

Язык: Английский

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Late‐Stage Peptide Diversification through Cobalt‐Catalyzed C−H Activation: Sequential Multicatalysis for Stapled Peptides

Angewandte Chemie International Edition, Год журнала: 2018, Номер 58(6), С. 1684 - 1688

Опубликована: Ноя. 30, 2018

Bioorthogonal late-stage diversification of structurally complex peptides has enormous potential for drug discovery and molecular imaging. In recent years, transition-metal-catalyzed C-H activation emerged as an increasingly viable tool peptide modification. Despite major accomplishments, these strategies largely rely on expensive palladium catalysts. We herein report unprecedented cobalt(III)-catalyzed activation, which enables the direct functionalization peptides, sets stage a multicatalytic activation/alkene metathesis/hydrogenation strategy assembly novel cyclic peptides.

Язык: Английский

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Nickel‐Catalyzed Electrooxidative C−H Amination: Support for Nickel(IV)

Chemistry - A European Journal, Год журнала: 2018, Номер 24(72), С. 19166 - 19170

Опубликована: Окт. 31, 2018

Abstract Nickel‐catalyzed electrochemical C−H aminations were accomplished by chemo‐ and position‐selective activation with ample scope. Detailed mechanistic studies highlighted a facile cleavage unique chemo‐selectivity, while cyclovoltammetric analysis provided support for nickel(II/III/IV) manifold.

Язык: Английский

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Iron(II)‐Catalyzed Site‐Selective Functionalization of Unactivated C(sp³)−H Bonds Guided by Alkoxyl Radicals

Angewandte Chemie International Edition, Год журнала: 2018, Номер 57(35), С. 11413 - 11417

Опубликована: Июль 17, 2018

Abstract An alkoxyl radical guided strategy for site‐selective functionalization of unactivated methylene and methine C−H bonds enabled by an Fe II ‐catalyzed redox process is described. The mild, expeditious, modular protocol allows efficient remote aliphatic fluorination, chlorination, amination, alkynylation structurally electronically varied primary, secondary, tertiary hydroperoxides with excellent functional‐group tolerance. application one‐pot 1,4‐hydroxyl non‐oxygenated alkane substrates initiated aerobic oxygenation also demonstrated.

Язык: Английский

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