Iron-Catalyzed Cross-Dehydrogenative Coupling of para-Quinone Methides with Formamides: In Situ Activation of C(sp2)–H Bonds DOI

Minjing Yuan,

Zikang Li,

Wenli Shang

et al.

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(22), P. 16663 - 16678

Published: Nov. 1, 2024

A novel and straightforward method for the iron-catalyzed regioselective cross-dehydrogenative coupling of para-quinone methides (p-QMs) with formamides has been developed, facilitated by in situ activation C(sp2)–H bonds formyl alkenyl substituents via a radical strategy. This does not require preactivation substrates, it can accommodate wide range p-QMs under optimized reaction conditions, resulting formation expected C-7 acetamides-functionalized moderate to good yields. The control experiments revealed that follows fundamental equation second-order kinetics. Additionally, an exploration Hammett effect was undertaken elucidate impact reaction. In combination DFT calculation, plausible mechanism proposed through meticulously controlled experiments.

Language: Английский

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
HFIP-Promoted Divergent Cycloadditions of Difluoroenoxysilanes with 2-Indolylmethanols: Synthesis of Fluoro 2H-Pyrano[3,4-b]indoles and gem-Difluoro Cyclopenta[b]indoles DOI

Rongyao Li,

Jing Zhang, Manman Sun

et al.

Organic Letters, Journal Year: 2024, Volume and Issue: 26(22), P. 4610 - 4615

Published: May 23, 2024

An oxa-6π-electrocyclization of difluoroenoxysilanes with diaryl 2-indolylmethanols has been developed. In addition, a rarely reported C3-nucleophilic [3+2] cycloaddition dialkyl disclosed. This divergent approach affording readily available as three-atom and C2 synthons provides rapid access to fluoro 2

Language: Английский

Citations

3
Photoinduced [4 + 2] Cycloaddition of Dienes and Quinonemethides DOI

Jobsy Jose,

Arun Kumar Yadav, Chandra Bhushan Tripathi

et al.

Chemical Communications, Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 1, 2024

A visible light-induced photoinduced cycloaddition of 1,3-dienes and p -quinonemethides is reported. The reaction proposed to proceed through an EDA complexation pathway with no external photocatalyst, oxidant or additives being used.

Language: Английский

Citations

1
Recent Advances on Fluorine Chemistry DOI Open Access
Mikhail Yu. Moskalik

International Journal of Molecular Sciences, Journal Year: 2024, Volume and Issue: 25(15), P. 8251 - 8251

Published: July 28, 2024

The purpose of this Special Issue is to showcase the latest findings in fluorine chemistry [...]

Language: Английский

Citations

1
Synthesis of Oxaspirocyclohexadienones via Lewis‐acid Catalyzed [2+3]‐Annulations of p‐Quinone Methides and Iodonium Ylides DOI

Mohd Mujahid,

Sanjeev Kumar, Nitin Pal Kalia

et al.

Advanced Synthesis & Catalysis, Journal Year: 2024, Volume and Issue: 366(15), P. 3283 - 3289

Published: June 6, 2024

Abstract Herein, we report a mild method for the synthesis of oxaspirocyclohexadienones by using combination Lewis acid‐HFIP mediated [2+3]‐annulation p ‐quinone methides ( p‐ QMs) and iodonium ylides. The proposed mechanism proceeds through one‐pot sequence carbonyl activation/cyclopropyl formation/Cloke‐Wilson rearrangement to provide broad range in moderate high yields. Interestingly, spiro‐annulated products were further converted tetrahydroxanthane derivatives via BF 3 .OEt 2 dienone‐phenol pathway. Moreover, also showed anti‐tuberculosis activity against Mycobacterium tuberculosis H37Ra ATCC25177.

Language: Английский

Citations

0
Iron-Catalyzed Cross-Dehydrogenative Coupling of para-Quinone Methides with Formamides: In Situ Activation of C(sp2)–H Bonds DOI

Minjing Yuan,

Zikang Li,

Wenli Shang

et al.

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(22), P. 16663 - 16678

Published: Nov. 1, 2024

A novel and straightforward method for the iron-catalyzed regioselective cross-dehydrogenative coupling of para-quinone methides (p-QMs) with formamides has been developed, facilitated by in situ activation C(sp2)–H bonds formyl alkenyl substituents via a radical strategy. This does not require preactivation substrates, it can accommodate wide range p-QMs under optimized reaction conditions, resulting formation expected C-7 acetamides-functionalized moderate to good yields. The control experiments revealed that follows fundamental equation second-order kinetics. Additionally, an exploration Hammett effect was undertaken elucidate impact reaction. In combination DFT calculation, plausible mechanism proposed through meticulously controlled experiments.

Language: Английский

Citations

0