Synthesis of Benzazepines Bearing Three Contiguous Carbon Stereocenters through Pd(II)-Catalyzed [3 + 2] Cycloaddition of N-Aryl Nitrones with Allenoates

The Journal of Organic Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Янв. 24, 2025

A cascade reaction of Pd(II)/dppben-catalyzed [3 + 2] cycloaddition N-aryl nitrones with allenoates and sequential reduction has been developed for the synthesis functionalized benzazepines bearing three contiguous carbon stereocenters in moderate to good yields ranging from 15 82% high diastereoselectivity. The obtained could be converted into various benzazepine scaffolds, an estrone-derived scaffold was prepared over four steps estrone. More importantly, chiral 88% ee value auxiliary.

Язык: Английский

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Base-Promoted Regioselective Annulation of Pyridinium Ylides and Bromoalkynes for the Chemodivergent Synthesis of Indolizines

The Journal of Organic Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Фев. 5, 2025

A base-promoted regioselective formal [3 + 2] annulation of pyridinium ylides with bromoalkynes is reported, producing a series substituent-diverse indolizines in generally good yields. mild K2CO3-promoted three-component cyclization and at 2:1 molar ratio delivered C2-acylmethylated indolizines, whereas C2-brominated were generated starting from bearing strong electron-withdrawing groups the unit by using 2,2,6,6-tetramethyl-1-piperidinyloxy as dehydrogenating reagent. The current synthetic methodology offers controllable modular approach to access different substitution patterns, featuring wide substrate scope, functional group compatibility, complete regioselectivity without demand any transition-metal catalysts.

Язык: Английский

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Iron(iii)/quinoxaline-derived N,N-ligand catalyzed oxygen transfer reaction of N-vinyl nitrones through selective 4π-electrocyclization and N–O bond cleavage

Organic Chemistry Frontiers, Год журнала: 2024, Номер 11(8), С. 2277 - 2282

Опубликована: Янв. 1, 2024

We describe an iron( iii )/quinoxaline-derived N,N-ligand promoted O -transfer reaction of N -vinyl nitrones through selective -4π-electrocyclization and N–O bond cleavage to prepare a variety 2,5-dihydrooxazoles in good yields.

Язык: Английский

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BF₃ ⋅ OEt₂ and Visible Light‐Controlled [3,3]‐ or [1,3]‐Rearrangement of Quinazolinone N−O Aryl Moieties

Advanced Synthesis & Catalysis, Год журнала: 2024, Номер 366(9), С. 2056 - 2062

Опубликована: Фев. 29, 2024

Abstract We described a base‐promoted O ‐arylation of N3‐hydroxyl quinazolinones with diaryliodonium salts and sequential BF 3 ⋅ OEt 2 visible light‐controlled [3,3]‐ or [1,3]‐rearrangements quinazolinone N−O aryl moieties to prepare variety 2‐(quinazolin‐4‐yloxy)phenols atropisomeric 3‐(2‐hydroxyphenyl)quinazolin‐4‐ones in 44%‐75% yields 28%‐70% yields, respectively. Mechanistic studies showed that HBF 4 generated situ from Et water served as the catalyst this process aryloxyquinazolinium are vital intermediates promoting [1,3]‐rearrangements. The were found undergo solely [3,3]‐rearrangement heating whereas [1,3]‐rearrangement occurred via radical under irradiation light. This method highlights formation based on use light prompt generating quinazolinones.

Язык: Английский

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Enantioselective synthesis of saddle-shaped eight-membered lactones with inherent chirality via organocatalytic high-order annulation

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Окт. 1, 2024

Язык: Английский

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Catalyst-Free Selective Synthesis of E-Tetrasubstituted Olefins via Tandem Reaction of 3-Acetyl-4-phenyl-1-oxaspiro[4.5]deca-3,6,9-triene-2,8-dione with Amine, C–C Bond Breakage, and Proton Transfer

The Journal of Organic Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Фев. 25, 2025

The Z- or E-selective syntheses of tetrasubstituted olefins present big challenges. Tremendous efforts are ongoing to overcome this issue, especially for acyclic structures. In work, an E-stereoselective synthetic method through tandem reaction 1,4-Michael addition 3-acetyl-4-phenyl-1-oxaspiro[4.5]deca-3,6,9-triene-2,8-dione with amine, C-C bond breakage, and proton transfer by intermolecular hydrogen bonds was revealed excellent atom economy without catalysts additives. A diverse set E-tetrasubstituted were obtained in 43% 93% yields functional group tolerance late-stage modifications complex drug molecules. mechanism proposed based on the deuterium-labeling experiment density theory (DFT) calculation.

Язык: Английский

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Selective 6π‐Electrocyclization of N‐Vinyl‐α,β‐Unsaturated Nitrones to Prepare Polysubstituted Pyridine Derivatives

Chinese Journal of Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Март 7, 2025

Comprehensive Summary Herein, we have developed a facile method for the synthesis of various polysubstituted pyridine derivatives through selective 6π‐electrocyclization N ‐vinyl‐ α , β ‐unsaturated nitrones. It was found that gold catalysts promoted carbon‐6π‐electrocyclization nitrones to afford 6‐alkenyl ‐oxides in 43%—75% yields, whereas copper facilitated oxygen‐6π‐electrocyclization give 6‐epoxy pyridines 41%—83% yields. The present features broad substrate scope, good functional group tolerance, high cyclization selectivity, and diversity scaffolds.

Язык: Английский

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Catalytic Schmittel-Type [2+2] Cycloaddition of γ-Alkynyl Diazoacetates with Terminal Alkynes for Accessing Cyclobuta[a]indenes

Organic Letters, Год журнала: 2025, Номер unknown

Опубликована: Март 17, 2025

Instead of the conventional [4+2] cycloaddition, a regioselective Schmittel-type [2+2] cycloaddition yne–allene esters, generated in situ from copper-catalyzed dediazotized coupling γ-alkynyl diazoacetates with terminal alkynes, is reported, enabling bicyclization process to produce diverse array C1-arylated cyclobuta[a]indenes moderate good yields. The protocol features wide functional group compatibility, mild reaction conditions, and experimental simplicity, holding significant potential for building new tricyclic cyclobutenes.

Язык: Английский

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PhI(OAc)₂-mediated aminoacyloxylation of β,γ-unsaturated hydrazones using Togni reagent II as an acyloxyl precursor

Organic & Biomolecular Chemistry, Год журнала: 2023, Номер 21(33), С. 6757 - 6761

Опубликована: Янв. 1, 2023

A metal-free protocol for the direct construction of C(sp2)-N and C-O bonds via a PhI(OAc)2-mediated dehydrogenative aminoacyloxylation β,γ-unsaturated hydrazones with Togni reagent II is reported. Initiated by carboxyl-containing species generated in situ from II, this method offers new solution regioselective functionalization at remote site on hydrazones, thus providing straightforward synthesis acyloxyl-substituted pyridazines. This reaction features broad substrate scope mild conditions.

Язык: Английский

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Direct Access to Quinone-Fused 5-Substituted-1,4-Benzodiazepine Scaffolds from Azidoquinones with/without [1,2]-Azide-Nitrogen Migration: Mechanistic Insights

The Journal of Organic Chemistry, Год журнала: 2023, Номер 88(23), С. 16315 - 16329

Опубликована: Ноя. 15, 2023

Seven-membered nitrogen heterocycles have a strong influence in drug discovery due to their inherent 3D character, which allows the ability explore vast conformational space with biological target. Notably, privileged 1,4-benzodiazepine scaffold is dominant treating central nervous system its binding affinity GABAA receptor. Herein, we report protocol for transformation of azidoquinones p-quinone fused 5-substituted-1,4-benzodiazepines (p-QBZDs) from InCl3-catalyzed intermolecular tandem cycloannulation amines and aldehydes. Detailed mechanistic studies reveal that EDA complex between InCl3 crucial determining reaction pathway. In absence formation, proceeds via intermediacy 2,3-bridged-2H-azirine followed by regiospecific addition an amine C═N/ring opening/cyclization deliver p-QBZD 1,2-azide-nitrogen migration. case through regioselective aza-Michael addition/nitrene insertion aldehyde subsequent cyclization imidazole as secondary product without This provides straightforward access redox-active quinone embedded diverse substrate scopes would find potential applications medicinal chemistry discovery.

Язык: Английский

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