A General Photocatalytic Strategy for Nucleophilic Amination of Primary and Secondary Benzylic C–H Bonds

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(33), P. 18487 - 18496

Published: Aug. 11, 2023

We report a visible-light photoredox-catalyzed method that enables nucleophilic amination of primary and secondary benzylic C(sp3)-H bonds. A novel amidyl radical precursor organic photocatalyst operate in tandem to transform bonds into carbocations via sequential hydrogen atom transfer (HAT) oxidative radical-polar crossover. The resulting carbocation can be intercepted by variety N-centered nucleophiles, including nitriles (Ritter reaction), amides, carbamates, sulfonamides, azoles, for the construction pharmaceutically relevant C(sp3)-N under unified reaction conditions. Mechanistic studies indicate HAT is radical-mediated operates reductive quenching pathway. These findings establish mild, metal-free, modular protocol rapid diversification library aminated products.

Language: Английский

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Recent Advances in C–H Functionalisation through Indirect Hydrogen Atom Transfer

Molecules, Journal Year: 2023, Volume and Issue: 28(16), P. 6127 - 6127

Published: Aug. 18, 2023

The functionalisation of C–H bonds has been an enormous achievement in synthetic methodology, enabling new retrosynthetic disconnections and affording simple equivalents for synthons. Hydrogen atom transfer (HAT) is a key method forming alkyl radicals from substrates. Classic reactions, including the Barton nitrite ester reaction Hofmann–Löffler–Freytag reaction, among others, provided early examples HAT. However, recent developments photoredox catalysis electrochemistry have made HAT powerful tool capable introducing wide range functional groups into bonds. Moreover, greater mechanistic insights stimulated development increasingly site-selective protocols. Site-selectivity can be achieved through tuning electron density at certain using additives, judicious choice reagent, solvent system. Herein, we describe latest methods functionalizing C–H/Si–H/Ge–H indirect between 2018–2023, as well critical discussion reagents, aspects, substrate scopes, background contexts

Language: Английский

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Copper/BINOL-Catalyzed Enantioselective C–H Functionalization toward Planar Chiral Ferrocenes Under Mild Conditions

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(6), P. 4030 - 4039

Published: Feb. 28, 2024

Copper-catalyzed enantioselective C–H activation proceeding through an inner-sphere mechanism remains a huge challenge. Herein, copper-catalyzed alkynylation with terminal alkynes assisted by 8-aminoquinoline using readily available (S)-BINOL as the chiral ligand was disclosed. The reaction proceeded under mild conditions catalytic amount of copper salt, providing range ferrocenes in good yields and enantioselectivities (0 °C, up to 77% yield 94% ee). alteration stoichiometric chemical oxidant renewable electricity is also feasible at ambient temperature, demonstrating robustness this copper/BINOL catalysis. Notably, first cupraelectrocatalyzed reaction. Gram-scale synthesis, versatile transformations, application resulting oxazoline–olefin asymmetric synthesis highlight utility protocols.

Language: Английский

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Visible-light induced direct C(sp³)–H functionalization: recent advances and future prospects

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(18), P. 5278 - 5305

Published: Jan. 1, 2024

This review summarizes the latest methodological advances in photocatalytic C(sp 3 )–H functionalization, with a particular emphasis on formation of C–P, C–B, C–S bonds, etc ., and some prominent efforts asymmetric C–H functionalization.

Language: Английский

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Recent advances in C(sp³)–N bond formation via metallaphoto-redox catalysis

Chemical Communications, Journal Year: 2024, Volume and Issue: 60(50), P. 6340 - 6361

Published: Jan. 1, 2024

In this review, the state-of-the-art advances in radical-involved C(sp 3 )–N bond formation via metallaphotoredox catalysis have been highlighted, which are organized according to different catalytic modes, reaction types, and substrate classes.

Language: Английский

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Heterogeneous Iridium-Catalyzed Carbene N–H Bond Insertion with α-Alkyl Diazo Esters

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(7), P. 4690 - 4698

Published: March 13, 2024

A heterogeneous iridium single-atom site catalyst (Ir-SA) was synthesized and investigated in catalyzing the carbene insertion reaction with challenging α-alkyl diazo ester substrates. With only 0.23 mol % loading, our Ir-SA demonstrated remarkable performance N–H bond reactions involving various (hetero) aryl amines coupled esters. Notably, case of using a chiral diamino substrate two reactive sites, exhibited high selectivity toward single insertion, leading to generation class unsymmetric ligands. Further mechanism study revealed that lower activation barrier associated step, as compared either β-hydride elimination or downstream dual accounted for observed this catalyzed by Ir-SA.

Language: Английский

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Unified approaches in transition metal catalyzed C(sp³)–H functionalization: recent advances and mechanistic aspects

Chemical Society Reviews, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Direct alteration of unactivated C–H bonds organic building blocks.

Language: Английский

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Copper-Catalyzed Enantioselective Three-Component Carboamidation of Styrenes with Alkanes and Amides

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: April 4, 2025

Efficient assembly of valuable chiral molecules from readily available and low-cost chemical feedstocks remains one the most challenging tasks in synthetic chemistry today. Radical-mediated three-component carboamination alkenes offers an attractive strategy for addressing this challenge. However, existing reports focus on racemic examples are largely limited to activated alkenes, preactivated alkylation reagents, or sufficiently active nucleophiles. Herein, we report a highly enantioselective carboamidation styrenes with unactivated alkanes weakly nucleophilic amides. Enantioselective control is achieved by using cationic copper catalysts. This method enables synthesis variety optically amides excellent enantioselectivity. Mechanistic studies reveal that reaction proceeds via hydrogen atom transfer alkane followed radical addition olefin.

Language: Английский

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Regio- and Enantioselective Nickel-Catalyzed Ipso- and Remote Hydroamination Utilizing Organic Azides as Amino Sources for the Synthesis of Primary Amines

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 23, 2024

Primary amines serve as key synthetic precursors to most other

Language: Английский

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Tertiary Amides as Directing Groups for Enantioselective C−H Amination using Ion‐Paired Rhodium Complexes

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(14)

Published: Feb. 13, 2024

Abstract Enantioselective C−H amination at a benzylic methylene is vital disconnection towards chiral benzylamines. Here we disclose that butyric and valeric acid‐derived tertiary amides can undergo highly enantioselective using an achiral anionic Rh complex ion‐paired with Cinchona alkaloid‐derived cation. A broad scope of compounds be aminated encompassing numerous arene substitutions, amides, two different chain lengths. Excellent tolerance ortho substituents was observed, which has not been achieved before in asymmetric intermolecular Rh. We speculate the amide group substrate engages hydrogen bonding interactions directly cation, enabling high level organisation transition state for amination. This contrast our previous work where bearing bond donor required. Control experiments led to discovery methyl ethers also function as proficient directing groups under optimised conditions, potentially acting acceptors. finding promise dramatically expand applicability catalysts.

Language: Английский

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