Tandem C/N-Difunctionalization of Nitroarenes: Reductive Amination and Annulation by a Ring Expansion/Contraction Sequence

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 145(1), P. 41 - 46

Published: Dec. 23, 2022

A synthetic method for the reductive transformation of nitroarenes into ortho-aminated and -annulated products is reported. The operates via exhaustive deoxygenation by an organophosphorus catalyst a mild terminal reductant to access aryl nitrenes, which after ring expansion, are trapped amine nucleophiles give dearomatized 2-amino-3H-azepines. Treatment these ring-expanded intermediates with acyl electrophiles triggers 6π electrocyclization extrude nitrogen atom restore aromaticity phenyl ring, delivers C–H functionalization 2-aminoanilide benzimidazole products.

Language: Английский

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Development of a Nickel-Catalyzed N–N Coupling for the Synthesis of Hydrazides

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(28), P. 15071 - 15077

Published: July 6, 2023

A nickel-catalyzed N-N cross-coupling for the synthesis of hydrazides is reported. O-Benzoylated hydroxamates were efficiently coupled with a broad range aryl and aliphatic amines via nickel catalysis to form in an up 81% yield. Experimental evidence implicates intermediacy electrophilic Ni-stabilized acyl nitrenoids formation Ni(I) catalyst silane-mediated reduction. This report constitutes first example intermolecular coupling compatible secondary amines.

Language: Английский

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Recent progress in the synthesis of N-substituted arylamines by reductive cross-coupling of nitroarenes

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(9), P. 2638 - 2664

Published: Jan. 1, 2024

This review describes the recent advances in different reaction types and catalytic systems for construction of C–NAr S–NAr bonds by nitroaromatic reductive cross-coupling.

Language: Английский

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Recent Advances in Catalytic Nitrogen–Nitrogen Bond Formation Reactions

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(8), P. 5735 - 5778

Published: April 1, 2024

The lack of effective strategies for direct construction nitrogen–nitrogen bonds has hampered developments in the synthesis and application molecules containing hydrazine or azo motifs. Attracted by their properties both material science medicinal chemistry, more attention been drawn to this area, resulting fast growth design azaheterocycles substituted hydrazines. This review focuses on efficient catalytic approaches toward formation N–N N═N through different strategies, including oxidative dehydrogenation, nitrene-transfer reaction, reductive coupling, some other recently developed methods.

Language: Английский

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Mild Amide Synthesis Using Nitrobenzene under Neutral Conditions

Organic Letters, Journal Year: 2022, Volume and Issue: 24(26), P. 4766 - 4771

Published: June 27, 2022

Amide synthesis is one of the most important transformations in organic chemistry due to broad application pharmaceutical drugs and materials. In this report, we describe a mild protocol for amide formation using readily available nitroarenes as nitrogen sources an inexpensive iron complex catalyst. Because use pH-neutral conditions avoidance strong oxidant or reductant, wide range aromatic aliphatic aldehydes well with various functional groups could be tolerated well. A plausible mechanism proposed based on detailed studies, which catalyst initiates radical process solvent plays key role O-atom acceptor.

Language: Английский

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Chemoselective Primary Amination of Aryl Boronic Acids by P^III/P^V═O-Catalysis: Synthetic Capture of the Transient Nef Intermediate HNO

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(20), P. 8902 - 8907

Published: May 12, 2022

A catalytic approach to intercept the transient HNO for a chemoselective primary amination of arylboronic acids is reported. phosphetane-based catalyst operating within PIII/PV═O redox cycling shown capture HNO, generated in situ by Nef decomposition 2-nitropropane, selectively install amino group at aryl Csp2 centers. The method furnishes versatile arylamines from acid substrates with preservation otherwise reactive functional groups.

Language: Английский

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Enabling Reductive C–N Cross-Coupling of Nitroalkanes and Boronic Acids by Steric Design of P(III)/P(V)═O Catalysts

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(18), P. 8242 - 8248

Published: May 2, 2022

An organophosphorus-catalyzed C–N bond-forming reductive coupling of nitroalkanes with arylboronic acids and esters is reported. The method shows excellent chemoselectivity for the nitro/boronic acid substrate pair, allowing synthesis N-(hetero)arylamines rich in functionalization. identification a sterically reduced phosphetane catalyst capable productive P(III)/P(V)═O redox manifold key enabling development. Combined experimental kinetics computational mechanistic studies show that affects post-rate-limiting steps to enable event preference deleterious side-paths.

Language: Английский

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Ligand‐Promoted Iron‐Catalyzed Nitrene Transfer for the Synthesis of Hydrazines and Triazanes through N‐Amidation of Arylamines

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 63(2)

Published: Nov. 24, 2023

Abstract Herein, we report that bulky alkylphosphines such as P t Bu 3 can switch the roles from actor to spectator ligands promote FeCl 2 ‐catalyzed N ‐amidation reaction of arylamines with dioxazolones, giving hydrazides in high efficiency and chemoselectivity. Mechanistic studies indicated phosphine could facilitate decarboxylation dioxazolones on Fe center, hydrogen bonding interactions between nitrenoid intermediates might play a role modulating delicate interplay ligand, arylamine, acyl nitrene N, favoring N−N coupling over N−P coupling. The new ligand‐promoted protocols offer convenient way access various challenging triazane compounds via double or sequential primary arylamines.

Language: Английский

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Photoinduced Difunctionalization of Diazenes Enabled by N–N Radical Coupling

Organic Letters, Journal Year: 2023, Volume and Issue: 25(36), P. 6671 - 6676

Published: Aug. 29, 2023

In this study, a metal-free difunctionalization strategy for diazenes was developed using range of bifunctionalization reagents. This involves unique N(sp3)–N(sp2) radical coupling between the hydrazine and imine radical. More than 30 triazane core motifs were constructed by installing imines various functional groups, including alkyl, phenyl, cyanoalkyl, sulfonyl on both ends nitrogen–nitrogen bond in an efficient manner.

Language: Английский

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Chiral Bisphosphine-Catalyzed Asymmetric Staudinger/aza-Wittig Reaction: An Enantioselective Desymmetrizing Approach to Crinine-Type Amaryllidaceae Alkaloids

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(20), P. 14136 - 14148

Published: April 20, 2024

An unprecedented chiral bisphosphine-catalyzed asymmetric Staudinger/aza-Wittig reaction of 2,2-disubstituted cyclohexane-1,3-diones is reported, enabling the facile access a broad range cis-3a-arylhydroindoles in high yields with excellent enantioselectivities. The key to success this work relies on first application bisphosphine DuanPhos reaction. effective reductive system has been established address challenging PV═O/PIII redox cycle associated catalyst. In addition, comprehensive experimental and computational investigations were carried out elucidate mechanism Leveraging newly developed chemistry, enantioselective total syntheses several crinine-type Amaryllidaceae alkaloids, including (+)-powelline, (+)-buphanamine, (+)-vittatine, (+)-crinane, have accomplished remarkable conciseness efficiency.

Language: Английский

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