Cobalt‐Catalyzed Radical Hydroamination of Alkenes with N‐Fluorobenzenesulfonimides

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(49), С. 25949 - 25957

Опубликована: Сен. 25, 2021

An efficient and general radical hydroamination of alkenes using Co(salen) as catalyst, N-fluorobenzenesulfonimide (NFSI) its analogues both nitrogen source oxidant was successfully disclosed. A variety alkenes, including aliphatic styrenes, α, β-unsaturated esters, amides, acids, well enones, were all compatible to provide desired amination products. Mechanistic experiments suggest that the reaction underwent a metal-hydride-mediated hydrogen atom transfer (HAT) with alkene, followed by pivotal catalyst controlled SN 2-like pathway between in situ generated organocobalt(IV) species nitrogen-based nucleophiles. Moreover, virtue modified chiral cobalt(II)-salen an unprecedented asymmetric version also achieved good excellent level enantiocontrol. This novel C-N bond construction opens new door for challenging hydrofunctionalization.

Язык: Английский

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Remote C(sp³)−H Acylation of Amides and Cascade Cyclization via N‐Heterocyclic Carbene Organocatalysis

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(15)

Опубликована: Фев. 3, 2022

Abstract The direct functionalization of inert C(sp 3 )−H bonds under environmentally benign catalytic conditions remains a challenging task in synthetic chemistry. Here, we report an organocatalytic remote acylation amides and cascade cyclization through radical‐mediated 1,5‐hydrogen atom transfer mechanism using N‐heterocyclic carbene as the catalyst. Notably, diversity nitrogen‐containing substrates, including simple linear aliphatic carbamates ortho ‐alkyl benzamides, can be successfully applied to this system. With established protocol, over 120 examples functionalized δ‐amino ketones isoquinolinones with diverse substituents were easily synthesized up 99 % yield mild conditions. robustness generality strategy further highlighted by successful unactivated late‐stage modification pharmaceutical molecules. Then, asymmetric control radical reaction was attempted proven feasible newly designed chiral thiazolium catalyst, moderate enantioselectivity obtained at current stage. Preliminary mechanistic investigations several reactions, KIE experiments, computational studies shed light on mechanism.

Язык: Английский

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N-Heterocyclic-Carbene-Catalyzed C–H Acylation via Radical Relay

Organic Letters, Год журнала: 2022, Номер 24(3), С. 944 - 948

Опубликована: Янв. 20, 2022

A method of N-fluorocarboxamide-directed N-heterocyclic-carbene (NHC)-catalyzed benzylic C-H acylation with aldehydes via the hydrogen atom transfer strategy is disclosed. This transformation involves a sequence single-electron transfer, 1,5-hydrogen and radical cross-coupling steps. offers facile access to various highly functionalized ketones exhibits good chemical yields functional group tolerance.

Язык: Английский

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Copper-Mediated Radical Fluorine-Atom Transfer to Sulfonyl Radical: A Dramatic 4-Methoxypyridine 1-Oxide Ligand Effect

ACS Catalysis, Год журнала: 2024, Номер 14(5), С. 3115 - 3127

Опубликована: Фев. 13, 2024

Although the transition metal-catalyzed radical fluorine atom transfer (FAT) strategy has emerged as a powerful tool for construction of C–F bonds, to our knowledge, this approach rarely been applied formation S–F bonds. Here, we report that 4-methoxypyridine 1-oxide can serve an inexpensive and simple yet effective ligand thus promote transformation copper-mediated challengeable FAT sulfonyl radicals, paving way assembly FSO2 group. Based on concept, three Cu(I)-catalyzed protocols involving site-selective intra- intermolecular fluorosulfonylation inert C(sp3)–H bonds 1,2-aminofluorosulfonylation inactivated alkenes have developed, enabling preparation C(sp3)-rich aliphatic fluorides cannot be easily synthesized by known methods. These practical operationally methods result in high functional group tolerance under mild conditions modification bioactive derivatives highly valued molecules. Detailed mechanistic studies indicate unique role facilitating such rare FATs via outer-sphere pathway.

Язык: Английский

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Copper-Catalyzed Chemoselective (Amino)fluorosulfonylation of Hydrocarbons via Intramolecular Fluorine-Atom Transfer

ACS Catalysis, Год журнала: 2024, Номер 14(6), С. 4318 - 4328

Опубликована: Март 6, 2024

Sulfonyl fluorides have found increasing applications as functional molecules in chemistry and biology. We herein report a copper-catalyzed atom-economical access to two categories of sulfonyl through radical relay strategy the presence an SO2 surrogate. The aliphatic C(sp3)–H bond N-fluoro-N-alkyl sulfonamides reacted via 1,5-hydrogen atom transfer (HAT) process, affording alkanesulfonyl with proximal amino group. On other hand, utilizing substrates containing proper C═C double resulted intramolecular olefin aminofluorosulfonylation, allowing synthesis fluorosulfonyl-functionalized pyrrolidines piperidines atom-transfer addition (ATRA). Both reaction systems proceeded under mild conditions, requiring no additional fluorine source. Experimental computational studies suggest that S–F coupling is likely achieved radical-rebound pathway. By taking advantage SuFEx multifunctionality products, method applicable late-stage modification bioactive compounds, drug ligation chemistry, organic synthesis.

Язык: Английский

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Recent Advances in the Functionalization of Remote C−H Bonds by Hofmann‐Löffler‐Freytag‐type Reactions

Advanced Synthesis & Catalysis, Год журнала: 2023, Номер 365(19), С. 3211 - 3226

Опубликована: Авг. 26, 2023

Abstract Nitrogen radicals are one of the most useful reactive intermediates for selective transposition via intramolecular hydrogen atom transfer (HAT). The Hofmann‐Löffler‐Freytag (HLF) reaction is a distinctive radical‐based approach in which nitrogen used remote C−H bond functionalization HAT. Due to its excellent regioselectivity and atomic economy, HLF represents new preparation valuable functional molecules. In this review, we provide brief overview recent research advances mediated HLF‐type reactions involving intermolecular cyclization, δ ‐site functionalization.

Язык: Английский

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Manganese-Catalyzed N–F Bond Activation for Hydroamination and Carboamination of Alkenes

Organic Letters, Год журнала: 2020, Номер 23(1), С. 207 - 212

Опубликована: Дек. 11, 2020

A visible-light-promoted method for generating amidyl radicals from N-fluorosulfonamides via a manganese-catalyzed N–F bond activation strategy is reported. This protocol employs simple manganese complex, Mn2(CO)10, as the precatalyst and cheap silane, (MeO)3SiH, both hydrogen-atom donor F-atom acceptor, enabling intramolecular/intermolecular hydroaminations of alkenes, two-component carboamination even three-component alkenes. wide range valuable aliphatic sulfonamides can be readily prepared using these practical reactions.

Язык: Английский

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Cobalt-Catalyzed Divergent Aminofluorination and Diamination of Styrenes with N-Fluorosulfonamides

Organic Letters, Год журнала: 2021, Номер 23(10), С. 4067 - 4071

Опубликована: Май 10, 2021

A cobalt-catalyzed aminofluorination reaction of styrenes with N-fluorosulfonamides serving as both the amination and fluorination agents has been developed. The switch selectivity in this catalytic from to diamination could be easily achieved by addition 1.0 equiv PPh3. Both transformations tolerated a wide array substrates under mild conditions.

Язык: Английский

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Cu(II)-Catalyzed N-Directed Distal C(sp³)–H Heteroarylation of Aliphatic N-Fluorosulfonamides

Organic Letters, Год журнала: 2022, Номер 24(4), С. 1055 - 1059

Опубликована: Янв. 26, 2022

A copper-catalyzed δ-regioselective C(sp3)-H heteroarylation of N-fluorosulfonamides has been developed. broad range heteroarenes were well tolerated and reacted with various to give the corresponding heteroarylated amides in good yields. Notably, all types (1°, 2°, 3°) δ-C(sp3)-H bonds could be regioselectively activated through 1,5-HAT process. This protocol provides a practical strategy for functionalization via forging C(sp3)-C(sp2) bond.

Язык: Английский

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Cobalt-catalyzed Divergent Markovnikov and Anti-Markovnikov Hydroamination

Organic Letters, Год журнала: 2021, Номер 24(1), С. 22 - 26

Опубликована: Дек. 15, 2021

Catalytic hydroamination of the readily available alkenes is among most straightforward means to construct diverse alkyl amines. To this end, facile access both regioselectivity, i.e., Markovnikov or anti-Markovnikov hydroamination, with minimum reaction-parameter alternation, remains challenging. Herein, we report a cobalt-catalyzed highly selective and divergent alkenes, in which switch regioselectivity achieved simply by variation addition sequence 9-BBN.

Язык: Английский

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