Visible Light‐Mediated, Acid‐Catalyzed, C−N Cross Dehydrogenative Coupling of Quinoxalin‐2(1H)‐ones with Carbazoles and Amides: Access to Fluorescent Probes Featuring Aggregate Induced Emission

Advanced Synthesis & Catalysis, Год журнала: 2023, Номер 365(24), С. 4684 - 4691

Опубликована: Ноя. 11, 2023

Abstract We demonstrate a photocatalyst and transition metal catalyst free photo‐activation of quinoxalin‐2(1 H )‐ones in visible light the presence an acid catalyst. The photoactivated )‐one species transfers its energy to oxygen which promotes C−N cross dehydrogenative coupling with nucleophilic partners such as carbazoles, azoles amides giving products 42–75% yields. Preliminary studies reveal )‐one‐carbazole adducts display fluorescent properties including Intramolecular Charge Transfer (ICT) Aggregate Induced Emission (AIE).

Язык: Английский

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Consecutive cross-dehydrogenative C–O and C–N construction for the synthesis of polyarene with AIE properties under electrochemical condition involving oxygen radical species

Green Chemistry, Год журнала: 2023, Номер 25(6), С. 2287 - 2292

Опубликована: Янв. 1, 2023

Regioselective C–H phenoxylation and azolation of phenol derivatives via consecutively O-radical participating pathway subsequent electro-induced nucleophilic substitution (S N Ar) between azoles was disclosed.

Язык: Английский

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PhI(OAc)₂/I₂‐Mediated Decarboxylative C₄‐Amination of Coumarin‐3‐Carboxylic Acids via C_sp2−H Dehydrogenative C−N Cross‐Coupling under Ambient Conditions

European Journal of Organic Chemistry, Год журнала: 2023, Номер 26(15)

Опубликована: Март 6, 2023

Abstract An efficient and straightforward protocol for accessing a new series of functionalized 4‐aminocoumarins from PIDA/I 2 ‐mediated decarboxylative C 4 ‐amination coumarin‐3‐carboxylic acids via direct sp2 −H dehydrogenative C−N cross‐coupling with secondary amines under ambient conditions has been accomplished. The notable advantages this are the tolerance diverse functional groups, mild reaction at temperature, moderate to good yields, short times (in minutes), high regioselectivity, gram‐scale applicability, eco‐friendliness. This is first report cross‐dehydrogenative coupling synthesizing 4‐aminocoumarins.

Язык: Английский

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Palladium/Norbornene-Cocatalyzed Ortho-Amination of Aryl Iodides: A Systematic Elucidation of the Mechanisms and Roles of Cs₂CO₃ Base via Computational and Mass Spectrometric Approaches

ACS Catalysis, Год журнала: 2023, Номер 13(13), С. 8588 - 8599

Опубликована: Июнь 14, 2023

The Catellani-type palladium/norbornene-cocatalyzed ortho-amination of aryl halides has been widely applied. Although a Pd(0)/Pd(II)/Pd(IV) mechanism is generally adopted, some key issues remain to be addressed. Combined mass spectrometry (MS) and theoretical study have carried out, the following observations conclusions are obtained: (1) MS studies detected Cs-containing PdIV complex (m/z = 752.0947) confirm existence intermediate; (2) density functional theory (DFT) calculations indicate that 2-iodotoluene more reactive than morpholine–OBz in Pd0(PPh3)2 oxidative addition form PdII (3) for aryl-NBE-palladacycle (ANP) species, Cs2CO3 as ligand coordinates better PPh3 by computation; (4) with involvement Cs2CO3, into intermediate becomes favored over C(sp2)–C(sp3) reductive elimination; (5) base effects K2CO3 also compared, which agreement experimental findings latter results much lower yield.

Язык: Английский

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Iodine-Catalyzed Radical C–H Amination of Nonaromatic Imidazole Oxides: Access to Cyclic α-Aminonitrones

The Journal of Organic Chemistry, Год журнала: 2023, Номер 89(1), С. 463 - 473

Опубликована: Дек. 13, 2023

A straightforward cross-dehydrogenative coupling approach to incorporate alicyclic amino residues into the structure of model cyclic aldonitrones, 2H-imidazole oxides, is reported. The elaborated C(sp2)–H functionalization achieved by employing amines in presence I2–tert-butyl hydroperoxide (TBHP) reagent system. As a result, series 19 novel heterocyclic derivatives were obtained yields up 97%. mechanistic study involving electron paramagnetic resonance spectroscopic experiments allowed radical nature reaction be confirmed. In particular, envisioned rationale comprises N-iodination amine, followed N–I bond homolysis resulting intermediate and subsequent amination nitrone moiety via newly generated nitrogen-centered radical.

Язык: Английский

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An aerobic copper-catalyzed multi-component reaction strategy for N′,N′-diaryl acylhydrazine synthesis: reactions and mechanism

Organic Chemistry Frontiers, Год журнала: 2023, Номер 11(4), С. 1132 - 1139

Опубликована: Дек. 20, 2023

A sequential multi-component reaction of aldehydes and aryl hydrazines for the synthesis N' , -diaryl acylhydrazines with high regioselectivity has been achieved via an aerobic copper-catalyzed process.

Язык: Английский

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Ni‐Catalyzed/mediated C−X (X=N, O, S) Bond Formation Chelation‐Assisted by Bidentate Directing Groups

ChemistrySelect, Год журнала: 2024, Номер 9(5)

Опубликована: Янв. 29, 2024

Abstract Recently, transition‐metal‐catalyzed C−H functionalization has attracted significant attention due to its potential applications in different fields. Among metals, nickel is regarded as a more sustainable 3d‐transition metal, which been widely explored. Therefore, this review focuses on the recent advances field of nickel‐catalyzed assisted with bidentate directing groups (DGs) construct C−X (N, S, O) bond. The latest advancement catalysed bond are reviewed and covers literatures from 2015–2022. In addition, substrate scope limitations well partial mechanism discussed.

Язык: Английский

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Photoredox-Catalyzed Alkene Amination: C(sp²)–H/N–H Radical–Radical Cross Dehydrogenative Coupling

Organic Letters, Год журнала: 2024, Номер 26(11), С. 2326 - 2331

Опубликована: Март 7, 2024

Direct alkene C–H/N–H cross dehydrogenative coupling is an infrequent, highly challenging transformation. Herein, a photoredox radical–radical cross-coupling reaction between ketene dithioacetal as persistent radical cation and azole nitrogen center (NCR) was developed. This direct amination proceeded through synergistic cobalt catalysis, with only H2 evolution. The showed excellent tolerance regio- stereospecific manner, expanding the scope of C(sp2)–N construction methods modes.

Язык: Английский

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Electrochemical Oxidative (4 + 2) Cyclization of Anilines and o-Phenylenediamines for the Synthesis of Phenazines

Organic Letters, Год журнала: 2024, Номер 26(18), С. 3756 - 3761

Опубликована: Апрель 28, 2024

Phenazines, crucial constituents of nitrogen-containing heterocycles, widely exist in functional compounds. Herein, we report an anodic oxidative (4 + 2) cyclization between anilines and

Язык: Английский

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Cooperative Phosphine-Photoredox Catalysis Enables N–H Activation of Azoles for Intermolecular Olefin Hydroamination

Опубликована: Апрель 30, 2024

Catalytic intermolecular olefin hydroamination is an enabling synthetic strategy that offers direct and atom-economical access to a variety of nitrogen-containing compounds from abundant feedstocks. However, despite numerous advances in catalyst design reaction development, N–H azoles with unactivated olefins remains unsolved problem synthesis. We report dual phosphine photoredox catalytic protocol for the structurally diverse medicinally relevant olefins. Hydroamination proceeds high anti-Markovnikov regioselectivity N-site selectivity. The mild conditions functional group tolerance permit rapid construction molecular complexity late-stage functionalization bioactive compounds. bond activation proposed proceed via polar addition heterocycle radical cation, followed by P–N α-scission phosphoranyl intermediate. Reac-tivity selectivity are classified BDFE nitrogen-centered (NCR) spin density, respectively, which can serve as useful predictive aid extending unseen azoles.

Язык: Английский

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