Enantioselective Nickel‐Catalyzed Electrochemical Radical Allylation

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(38)

Опубликована: Авг. 1, 2022

A simplified and appealing strategy via a chiral catalyst to facilitate the electrochemical process provide asymmetric induction of radical reactions is particularly desirable would have potential applications in electrosynthesis, organic chemistry, drug discovery. Here, we introduced novel electrolytic system that diverts standard ionic reactivity new catalytic functions, enabling mechanistically distinct single-electron transfer-based enantioselective routes exhibit brand-new pattern reactivity-electricity-driven catalysis as privileged platform for allylation. The nickel-catalyzed activation nucleophiles triggered transfer catalyst-bound cation intermediate, which could be applied an alternative development stereocontrolled reactions.

Язык: Английский

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Regiodivergent C−H Acylation of Arenes by Switching from Ionic‐ to Radical‐Type Chemistry Using NHC Catalysis

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(27)

Опубликована: Апрель 24, 2023

The Friedel-Crafts acylation reaction, which belongs to the class of electrophilic aromatic substitutions is a highly valuable and versatile reaction in synthesis. Regioselectivity predictable determined by electronic as well steric factors (hetero)arene substrate. Herein, radical approach for arenes heteroarenes presented. C-H achieved through mild cooperative photoredox/NHC catalysis with cross-coupling an arene cation NHC-bound ketyl key step. As compared classical acylation, regiodivergent outcome observed upon switching from ionic mode. In these divergent reactions, aroyl fluorides act reagents both process.

Язык: Английский

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1,2‐Difunctionalization of Acetylene Enabled by Light

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(16)

Опубликована: Фев. 27, 2023

Although the direct conversion of gaseous acetylene into value-added liquid commodity chemicals is becoming increasingly attractive, majority established methodologies are focused on cross-coupling, hydro-functionalization, and polymerization. Herein, we describe a 1,2-difunctionalization method that inserts directly readily available bifunctional reagents. This provides access to diverse C2-linked 1,2-bis-heteroatom products in high regio- stereoselectivity along with opening up previously unexplored synthetic directions. In addition, demonstrate this method's potential by converting obtained functionalized molecules chiral sulfoxide-containing bidentate ligands. Using combination experimental theoretical methods, mechanism for insertion reaction was investigated.

Язык: Английский

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Radical Carbonyl Propargylation by Dual Catalysis

Angewandte Chemie International Edition, Год журнала: 2020, Номер 60(5), С. 2464 - 2471

Опубликована: Окт. 6, 2020

Carbonyl propargylation has been established as a valuable tool in the realm of carbon-carbon bond forming reactions. The 1,3-enyne moiety recognized an alternative pronucleophile above transformation through ionic mechanism. Herein, we report for first time, radical carbonyl dual chromium/photoredox catalysis. A library homopropargylic alcohols bearing all-carbon quaternary centers could be obtained by catalytic three-component coupling 1,3-enynes, aldehydes and suitable precursors (41 examples). This redox-neutral multi-component reaction occurs under very mild conditions shows high functional group tolerance. Remarkably, bench-stable, non-toxic, inexpensive CrCl3 employed chromium source. Preliminary mechanistic investigations suggest radical-polar crossover mechanism, which offers complementary novel approach towards preparation synthetic architectures from simple chemicals.

Язык: Английский

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Functionalization of α‐C(sp³)−H Bonds in Amides Using Radical Translocating Arylating Groups

Angewandte Chemie International Edition, Год журнала: 2020, Номер 60(7), С. 3561 - 3565

Опубликована: Ноя. 20, 2020

α-C-H arylation of N-alkylamides using 2-iodoarylsulfonyl radical translocating arylating (RTA) groups is reported. The method allows the construction α-quaternary carbon centers in amides. Various mono- and disubstituted RTA-groups are applied to primary, secondary, tertiary α-C(sp

Язык: Английский

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Direct Access to α‐Aminosilanes Enabled by Visible‐Light‐Mediated Multicomponent Radical Cross‐Coupling

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(43), С. 23335 - 23341

Опубликована: Авг. 25, 2021

α-Aminosilanes are an important class of organic compounds that show biological activity. In this communication, a new approach to α-aminosilanes utilizes photoredox catalysis enable three-component coupling organo(tristrimethylsilyl)silanes with feedstock alkylamines and aldehydes is presented. A wide range highly functionalized can be obtained in good yields under mild conditions. Both primary amines secondary compatible transformation. Moreover, optically pure accessible by using chiral amines. Mechanistic studies indicate reactions proceed through radical/radical cross-coupling silyl radicals α-amino alkyl radicals.

Язык: Английский

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Progress in Convergent Paired Electrolysis

Chemistry - A European Journal, Год журнала: 2022, Номер 28(47)

Опубликована: Июнь 8, 2022

Convergent paired electrolysis combines both anodic and cathodic reactions simultaneously in an electrochemical transformation. It provides a highly energy-efficient divergent approach to conventionally challenging useful structures. However, the physical separation of two half-electrode makes it extremely difficult couple intermediates arising from electrodes. In this concept article, four strategies used convergent will be discussed perspective reaction mechanism: a) metal-catalyzed electrolysis, b) enabled by persistent radical effects, c) microfluidic chemistry applied d) alternating current electrolysis.

Язык: Английский

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Mechanochemistry Drives Alkene Difunctionalization via Radical Ligand Transfer and Electron Catalysis

Advanced Science, Год журнала: 2024, Номер 11(29)

Опубликована: Июнь 3, 2024

Abstract A general and modular protocol is reported for olefin difunctionalization through mechanochemistry, facilitated by cooperative radical ligand transfer (RLT) electron catalysis. Utilizing mechanochemical force catalytic amounts of 2,2,6,6‐tetramethylpiperidinyloxyl (TEMPO), ferric nitrate can leverage nitryl radicals, nitrooxy‐functional group via RLT, mediate an catalysis cycle under room temperature. diverse range activated unactivated alkenes exhibited chemo‐ regioselective 1,2‐nitronitrooxylation solvent‐free or solvent‐less conditions, showcasing excellent functional tolerance. Mechanistic studies indicated a significant impact mechanochemistry highlighted the nature this nitrative process.

Язык: Английский

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Deconstructive Oxygenation of Unstrained Cycloalkanamines

Angewandte Chemie International Edition, Год журнала: 2019, Номер 59(10), С. 3900 - 3904

Опубликована: Дек. 23, 2019

A deconstructive oxygenation of unstrained primary cycloalkanamines has been developed for the first time using an auto-oxidative aromatization promoted C(sp3 )-C(sp3 ) bond cleavage strategy. This metal-free method involves substitution reaction with hydrazonyl chlorides and subsequent annulation to in situ generate pre-aromatics, followed by N-radical-promoted ring-opening further 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) m-cholorperoxybenzoic acid (mCPBA). Consequently, a series 1,2,4-triazole-containing acyclic carbonyl compounds were efficiently produced. protocol features one-pot operation, mild conditions, high regioselectivity efficiency, broad substrate scope, is compatible alkaloids, osamines, peptides, as well steroids.

Язык: Английский

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Transition‐Metal‐Free Oxidative Cross‐Coupling of Tetraarylborates to Biaryls Using Organic Oxidants

Angewandte Chemie International Edition, Год журнала: 2020, Номер 59(36), С. 15468 - 15473

Опубликована: Март 11, 2020

Abstract Readily prepared tetraarylborates undergo selective (cross)‐coupling through oxidation with Bobbitt's salt to give symmetric and unsymmetric biaryls. The organic oxoammonium can be used either as a stoichiometric oxidant or catalyst in combination situ generated NO 2 molecular oxygen the terminal oxidant. For selected cases, oxidative coupling is also possible /O without any additional nitroxide‐based cocatalyst. Transition‐metal‐free catalytic ligand cross‐coupling of unprecedented introduced method provides access various biaryl heterobiaryl systems.

Язык: Английский

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