Synthesis of Polysubstituted Pyrroles through a Formal [4 + 1] Cycloaddition/E1cb Elimination/Aromatization Sequence of Sulfur Ylides and α,β-Unsaturated Imines

Cheng, Bei‐Yi; Wang, Yani; Li, Tianren; Lu, Liang‐Qiu; Xiao, Wen‐Jing

doi:10.1021/acs.joc.7b01931

Cited by 38 publications

(12 citation statements)

References 47 publications

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“…These results showed that the S 1 of BQMP-b − had a shorter bond between C2-O1 (1.26 Å, right) in the binaphthol ring group compared to that of BQMP-b − in the ground state (1.29 Å, left), which further suggested that this C–O bond had high tendencies to form the C=O bond. According to the mechanism of an E1cb elimination reaction, the lone electron on the O1 anion quickly moved to the neighboring carbon atom C2 in the binaphthol ring to form a carbanion and then transferred rapidly to the C3 position due to the conjugated structure in the binaphthol ring group (Scheme 2), expelling the leaving group of NMe 3 and forming the C=C double bond simultaneously [27,28]. It is reasonable that the reactive efficiency for generating QM in a strong basic aqueous solution could be much higher than that produced by a GSIPT process in mild MeCN:H 2 O solutions.…”

Section: Resultsmentioning

confidence: 99%

Time-Resolved Spectroscopic and Density Functional Theory Investigation of the Photogeneration of a Bifunctional Quinone Methide in Neutral and Basic Aqueous Solutions

Yan

Lan

et al. 2018

Molecules

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Binol quinone methides (BQMs) can be generated from 1,1′-(2,2′-dihydroxy-1,1′-binaphthyl-6,6′-diyl)bis(N,N,N-trimethylmethanamiuium) bromide (BQMP-b) in a 1:1 MeCN:H2O mixed solution via a ground state intramolecular proton transfer (GSIPT), as mentioned in our previously reported studies. Here, the photoreaction of BQMP-b in neutral and basic aqueous solution (pH = 7, 10, 12) was investigated to explore the possible mechanisms and the key intermediates produced in the process of the photoreaction and to examine whether they are different from those in a neutral mild-mixed MeCN:H2O solution. The studies were conducted using femtosecond transient absorption (fs-TA), nanosecond transient absorption (ns-TA), and nanosecond time-resolved resonance Raman spectroscopy (ns-TR3) in conjunction with results from density functional theory (DFT) computations. The results showed that BQMP-b was deprotonated initially and produced BQMs species more effectively through an E1bc elimination reaction in a strong basic aqueous condition (pH = 12), which differed from the reaction pathway that took place in the solution with pH = 7 or 10. A related single naphthol ring molecule 1-(6-hydroxynaphthalen-2-yl)-N,N,N-trimethylmethanaminium bromide (QMP-b) that did not contain a second naphthol ring was also investigated. The related reaction mechanisms are elucidated in this work, and it is briefly discussed how the mechanisms vary as a function of aqueous solution pH conditions.

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Section: Resultsmentioning

confidence: 99%

Time-Resolved Spectroscopic and Density Functional Theory Investigation of the Photogeneration of a Bifunctional Quinone Methide in Neutral and Basic Aqueous Solutions

Yan

Lan

et al. 2018

Molecules

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“…In 2017, Xiao and co-workers [58] reported a [4＋1] cycloaddition reaction of sulfurylides and α,β-unsaturated imines for preparation of polysubstituted pyrroles through a formal [4＋1] cycloaddition/E1cb elimination/aromatization process (Scheme 34). Such a reaction features simple operation, high efficiency, mild and metal-free conditions, and the readily available starting materials.…”

Section: Scheme 33 Palladium-catalyzed Reaction Of Imines Aryl Iodides and Comentioning

confidence: 99%

Recent Advances on Pyrrole Synthesis through Different Annulation Modes

Xu¹,

Chen²,

Zhang³

et al. 2021

Chinese Journal of Organic Chemistry

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“…Bei‐Yi Cheng et al discovered a reaction sequence comprising a formal [4+1] cycloaddition, an E1cb elimination, and an aromatization process [100] . By doing so, polysubstituted pyrroles 311 were achieved from easily available chemicals, sulfur ylides 309 , and α , β ‐unsaturated imines 310 .…”

Section: Cycloaddition Reactionsmentioning

confidence: 99%

Recent Advances for the Synthesis of N‐Unsubstituted Pyrroles

et al. 2021

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Pyrroles are an interesting class of heterocyclic compounds due to their widespread use both in medical chemistry and in the chemistry of new materials. Search and development of new effective methods for the synthesis of the pyrrole ring is an urgent task. Along with this, the systematization of already known synthesis methods is an equally important task. Herein, we focused on the results of the synthesis of NH‐pyrroles that have been obtained since 2015.

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Synthesis of Polysubstituted Pyrroles through a Formal [4 + 1] Cycloaddition/E1cb Elimination/Aromatization Sequence of Sulfur Ylides and α,β-Unsaturated Imines

Cited by 38 publications

References 47 publications

Time-Resolved Spectroscopic and Density Functional Theory Investigation of the Photogeneration of a Bifunctional Quinone Methide in Neutral and Basic Aqueous Solutions

Time-Resolved Spectroscopic and Density Functional Theory Investigation of the Photogeneration of a Bifunctional Quinone Methide in Neutral and Basic Aqueous Solutions

Recent Advances on Pyrrole Synthesis through Different Annulation Modes

Recent Advances for the Synthesis of N‐Unsubstituted Pyrroles

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