Divergent Annulations of 5,6‐Dihydro‐4H‐1,2‐Oxazine N‐Oxides and Enol Diazoacetates for the Switchable Chemoselective Synthesis of Fused 1,2‐Oxazine Derivatives DOI

Stepan N. Ostarkov,

Yana I. Lichtenstein,

Yulia A. Antonova

et al.

European Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 9, 2024

Abstract Reactions of 5,6‐dihydro‐4 H ‐1,2‐oxazine N ‐oxides with enol diazoacetates were studied. A particular reaction path depends on the amount catalyst and order addition substrates. Use Rh 2 (Oct) 4 (2 mol.%) leads to chemoselective [3+3]‐annulation producing 1,2‐oxazine‐fused 1,2‐oxazine derivatives. With lower loadings (0.03 are converted cyclopropene derivatives, which in situ react via tandem [3+2]‐cycloaddition‐rearrangement oxazine‐fused aziridines. Both transformations showed a wide substrate scope produced target products good yields diastereoselectivity, thus allowing selective preparation these rare heterocyclic systems. mechanistic rationale for observed chemo‐ stereo‐ selectivities was proposed.

Language: Английский

Visible-Light-Induced [4 + 3]-Annulation of Carbonyl Ylides with Alkenyl Pyrazolinone for Constructing [4.2.1]-Oxo-Bridged Oxocine Skeleton DOI

Dong-Sheng Ji,

Xin Zhang,

Peiqin Zhang

et al.

Organic Letters, Journal Year: 2025, Volume and Issue: 27(2), P. 709 - 714

Published: Jan. 7, 2025

Herein, we present a visible-light-induced protocol for the synthesis of highly functionalized oxo-bridged oxocine skeletons. This method generates carbenes via ortho-acyl diazo compounds, which are rapidly intercepted by oxygen atom an intermolecular acyl group to form cyclic 1,3-dipole. The in situ generated reactive 1,3-dipole undergoes facile formal [4 + 3] cycloaddition with alkenyl pyrazolinone, yielding [4.2.1]-oxo-bridged compounds.

Language: Английский

Citations

2
Photoinduced Formal Cross-[3+3] Cycloaddition of Vinyldiazo Reagents with Acceptor-Only Diazoalkanes DOI
Yang Xie, Lihua Zhang, Jun Xuan

et al.

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: March 22, 2025

In this study, we devised an innovative approach for the synthesis of pyrazine derivatives through a photoinduced formal cross-[3+3] cycloaddition between vinyldiazo reagents and acceptor-only diazoalkanes. This method leverages differential reactivity two distinct diazo compounds: reagents, which upon visible light irradiation form key cyclopropane intermediates, diazoalkanes, function as 1,3-dipoles to capture photogenerated reactive species. The reactions proceed exclusively under light, yielding 1,4-dihydropyridazines with broad substrate scope compatibility various functional groups. Importantly, synthesized can be readily converted other valuable products. mechanism, elucidated UV–vis absorption studies, deuterium labeling experiments, control in situ NMR spectroscopy, provides clear understanding observed reactivity.

Language: Английский

Citations

0
Blue Light-Induced Diazo Cross-Coupling: Synthesis of Allyldiazo Compounds through Reshuffling of Functionalities DOI Creative Commons
Jiabao Tian, Jiahao Ling, Yanan Wang

et al.

Chemical Science, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

In this paper, we describe a new type of cross-coupling between simple diazo and vinyldiazo compounds that gives access to unusual allyldiazo products. Blue light discriminates two towards free carbene formation, triggering sequential cyclopropenation, (3+2) cycloaddition ring opening rearrangement processes. This strategy involves an overall reshuffle functionality olefinic carbons with extrusion nitrogen. Mechanistic studies including 15N-labelling experiment demonstrate the products derives from compounds, while reagents are selectively decomposed via energy transfer thioxanthone photocatalyst. The obtained can be efficiently converted into synthetically useful structures such as 1,3-dienes, gem-difluoro-1,4-diene, hydrazine, dihydropyrazole, pyridazine, bicyclobutane.

Language: Английский

Citations

0
Lewis-Acid-Catalyzed Diastereoselective [4 + 2] Cycloaddition of Vinyldiazo Compounds with N-Acyliminium Cations DOI
Xiaofei Chen, Yi Gao,

Shuyu Yu

et al.

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 28, 2025

An FeCl3-catalyzed [4 + 2] cycloaddition of vinyldiazo compounds with N-acyliminium cations generated from 3-hydroxyisoindolinones is described. A series diazo-containing isoindolo[2,1-a]quinolinones were constructed in good yields excellent diastereoselectivities, including those three contiguous stereogenic centers. The resultant products readily converted into various isoindolo[2,1-a]quinolinone derivatives based on the rich chemistry remaining diazo functionality.

Language: Английский

Citations

0
Photolytic Access to Oxaspirodecanes and Chromenes from Vinyldiazo Ester Cycloaddition with p-Quinones: A Vinylcarbene Is Not Involved DOI

Soumen Biswas,

Ramon Trevino,

Seth O. Fremin

et al.

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

Published: March 26, 2025

Synthetic methods that provide access to skeletally diverse heterocyclic motifs are poised accelerate drug discovery and streamline the synthesis of advanced intermediates materials. However, development such synthetic necessitates leveraging previously unexplored mechanistic pathways. We report herein an efficient blue light-emitting diode light-induced reaction vinyldiazoacetates quinones produces spirocyclic dihydrofurans, featuring synthetically challenging oxaspiro[4,5]decane core numerous medicinal agents, agrochemicals, natural products. In a departure from well-established photochemical reactivity diazo compounds, these reactions do not involve vinylcarbene formed by photolytic dinitrogen extrusion. Instead, they result photoexcitation quinone its triplet state with subsequent energy transfer vinyldiazo ester. The addition vinylogous carbon vinyldiazoacetate oxygen affords diradical collapses dihydrofuran upon loss dinitrogen. A strain release-driven Bro̷nsted acid-catalyzed rearrangement products unravels fused bicyclic ring system equally medicinally valuable chromenes, enabling facile skeletal diversification important motifs.

Language: Английский

Citations

0
Synthesis of thiopyran derivatives via [4 + 2] cycloaddition reactions DOI Creative Commons

Maryam Mousavi-Ebadia,

Javad Safaei‐Ghomi, Masoumeh Jadidi Nejad

et al.

RSC Advances, Journal Year: 2025, Volume and Issue: 15(14), P. 11160 - 11188

Published: Jan. 1, 2025

In this review, we provide a comprehensive overview of the synthesis thiopyran family compounds via cycloaddition reactions, with examples spanning from year 2000 to present.

Language: Английский

Citations

0
Scandium Triflate Catalyzed Cycloadditions of Vinyl Diazo Compounds and In Situ Formed Naphthoquinone Methides DOI

Yueyan Yin,

Jie Zhan, Ren Liu

et al.

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: April 17, 2025

Vinyl diazo carbonyl compounds have received great attention and are widely employed in the cycloadditions of situ formed reactive intermediates. Metal carbenes predominantly involved cycloadditions, transformations vinyl that do not proceed via metal carbene pathway been seldom reported. Herein, scandium-catalyzed 2-naphthoquinone-8-methides achieved, naphthalene-fused polycyclic products were obtained up to 88% yield. In transformation, nucleophilic conjugate addition generates diazonium intermediates, which undergo an intramolecular Friedel-Crafts reaction transesterification yield final product.

Language: Английский

Citations

0
A photochemical strategy towards Michael addition reactions of cyclopropenes DOI Creative Commons
Yaseen Hussain,

R. Prasanna,

Claire Empel

et al.

Published: Aug. 16, 2024

The development of Michael addition reactions to conjugated cyclopropenes is a challenge in synthesis due the fleeting and reactive nature such strained acceptor systems. Herein, photochemical approach towards reported that serves as strategic entry point densely functionalized cyclopropanes diastereoselective fashion. process involves light-mediated generation transient cyclopropenyl α,β-unsaturated esters from vinyl diazo esters, followed by an organic base catalyzed nucleophilic N-heterocycles directly access β-N-heterocyclic cyclopropanoic esters. With this synergistic approach, various trisubstituted bearing N-heteroaryl N-heterocyclic rings indole, pyrrole, benzimidazole, isatin, pyridinone quinolinone were accessed efficiently good yield decent diastereoselectivities. Further, β-indolyl acids have been synthesized successfully evaluated FABP-4 inhibitors. Theoretical calculations performed elucidate mechanism which was further supported experimental findings.

Language: Английский

Citations

1
Divergent Annulations of 5,6‐Dihydro‐4H‐1,2‐Oxazine N‐Oxides and Enol Diazoacetates for the Switchable Chemoselective Synthesis of Fused 1,2‐Oxazine Derivatives DOI

Stepan N. Ostarkov,

Yana I. Lichtenstein,

Yulia A. Antonova

et al.

European Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 9, 2024

Abstract Reactions of 5,6‐dihydro‐4 H ‐1,2‐oxazine N ‐oxides with enol diazoacetates were studied. A particular reaction path depends on the amount catalyst and order addition substrates. Use Rh 2 (Oct) 4 (2 mol.%) leads to chemoselective [3+3]‐annulation producing 1,2‐oxazine‐fused 1,2‐oxazine derivatives. With lower loadings (0.03 are converted cyclopropene derivatives, which in situ react via tandem [3+2]‐cycloaddition‐rearrangement oxazine‐fused aziridines. Both transformations showed a wide substrate scope produced target products good yields diastereoselectivity, thus allowing selective preparation these rare heterocyclic systems. mechanistic rationale for observed chemo‐ stereo‐ selectivities was proposed.

Language: Английский

Citations

0