Benzene construction via organocatalytic formal [3+3] cycloaddition reaction

Zhu, Tingshun; Zheng, Pengcheng; Mou, Chengli; Yang, Song; Song, Baoan; Robin, Yonggui

doi:10.1038/ncomms6027

Cited by 103 publications

(48 citation statements)

References 67 publications

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“…In 2014, Chi and co-workers reported an NHC-catalyzed (3 + 3) benzannulation reaction of enals 118 and unsaturated ketones 119, producing the tetra-substituted benzenes 121 with high yields. [56] Experiment results showed that different NHC catalysts played key roles in the reaction, and when N-Mes imidazolium 120 was applied as the NHC precursor, the product 121 was formed in 88% isolated yield. Further investigation showed that the catalyst loading of 120 could be decreased to 5 mol% with acceptable yield (Scheme 28).…”

Section: N-heterocyclic Carbene (Nhc)-catalyzed Benzannulation Reactionsmentioning

confidence: 99%

Recent Advances in Organocatalyst‐Mediated Benzannulation Reactions

2020

Adv Synth Catal

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Aromatic compounds are omnipresent in organic chemistry, which are the broadest skeletons of bioactive molecules, medicines, and materials. Due to their importance, conventional methods to assemble aromatic rings have attracted considerable attention. The direct formation of benzene cores from readily available acyclic precursors offers a highly versatile and superior approach to prepare both small organic molecules and sophisticated natural products. Recently, organocatalyst-mediated annulation reaction, including phosphine-, tertiary amine-, secondary amine-, primary amine-, and NHC-mediated benzannulation reactions, is considered as an efficient method to access multi-substituted arenes. In this review, we will emphasize the selected examples of organocatalyst-mediated benzannulation reactions of available acyclic precursors for the construction of diverse aromatics.

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Section: N-heterocyclic Carbene (Nhc)-catalyzed Benzannulation Reactionsmentioning

confidence: 99%

Recent Advances in Organocatalyst‐Mediated Benzannulation Reactions

2020

Adv Synth Catal

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“…In addition, the same research group also reported another base‐mediated [3+3] benzannulation reaction that used commercially available enals 49 and enones 50 for the construction of functionalized benzene derivatives 51 . The products were synthesized with excellent regioselectivities and this method constituted a concise pathway for the synthesis of complex organic molecules (Scheme ) . The reaction was performed in THF at room temperature by using 5 mol % of an NHC catalyst, 1.5 equivalents of a base, and two equivalents of an oxidant.…”

Section: Cs2co3‐mediated Benzannulation Reactionsmentioning

confidence: 99%

Recent Progress in Transition‐Metal‐Free, Base‐Mediated Benzannulation Reactions for the Synthesis of a Diverse Range of Aromatic and Heteroaromatic Compounds

et al. 2018

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Benzene and itsderivativesare the most abundant substructures of several interesting classes of compound, such as bioactive molecules. Owing to their importance, the development of methods for their constructionh as attracted considerable attention.H owever,t he regioselectives ynthesis of polysubstituted aromatic and heteroaromatic compounds by using aromatic substitution is challenging, because it provides derivatives with restricted substitution patterns. Therefore, the benzannulation reaction-the assembly of benzene derivatives from acyclicp recursors-constitutes as uperior and highly versatile approach to polysubstituted aromatic and heteroaromatic compounds,a nd variouse fficient benzannulation reactions have been reported.R epresentative examples include Cs 2 CO 3 , t-BuOK,a nd DBU-catalyzed reactions for the construction of valuableb enzene derivatives. The central objective of this Focus Review is to highlight base-mediated benzannulation reactions under transitionmetal-free conditions for the construction of aromatic and heteroaromatic compounds.[a] Dr.Recently,P an and co-workers investigated the K 2 CO 3 -catalyzed cascade benzannulation reaction of b-keto sulfones 1 with acetylene ketones 2 by using 30 %m ol K 2 CO 3 without other additives,w hich afforded new sulfonylbenzene derivatives 3 in good yields through ab enzannulation reaction (Scheme 1a). [18] Av ariety of electron-donating ande lectron-withdrawing groups were well-tolerated under the optimized reaction conditions. The proposed reactionpathway proceeded through se-quentialM ichael addition, intramolecular cyclization, hydrogen abstraction, and dehydration reactions (Scheme 1b).Scheme55. Synthesis of unsymmetrical biaryls from the annulation/aromatizationr eactionsof1 ,4-pentanedienes with nitroalkanes.Scheme56. DBU-promoted [5+ +1] annulation reaction of a-alkenoyl ketene-S,S-acetalswith nitroalkanes.

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“…Chi et al. verwendeten NHC‐generierte Azoliumdienolat‐Intermediate zum Aufbau mehrfach substituierter Benzolderivate (Schema ) . Die Reaktionen von 13 mit den Michael‐Akzeptoren 72 verliefen effizient in Gegenwart des Imidazoliumsalzes C‐16 als NHC‐Vorstufe und von O1 als Oxidationsmittel.…”

Section: [4+2]‐cycloadditionen Von Michael‐akzeptorenunclassified

Katalyse durch N‐heterocyclische Carbene über Azoliumdienolate: eine effiziente Strategie für enantioselektive Funktionalisierungen an entfernten Positionen

et al. 2018

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Die Katalyse durch N‐heterocyclische Carbene (NHCs) ist zu einer effizienten Strategie in der organischen Synthese geworden. In den letzten Jahren wurden etliche Übersichtsartikel veröffentlicht, die NHC‐katalysierte Umwandlungen unter Beteiligung von Breslow‐Intermediaten, Acylazolium‐ und α,β‐ungesättigten Acylazolium‐Intermediaten, Homoenolatäquivalenten sowie Azoliumenolaten behandelten. Doch erst in letzter Zeit wurden durch NHCs erzeugte Azoliumdienolat‐Intermediate in der asymmetrischen Synthese, insbesondere in Cycloadditionen, zur Funktionalisierung entfernter Positionen genutzt. Dieser Kurzaufsatz beleuchtet alle Entwicklungen und neuere Fortschritte für NHC‐katalysierte asymmetrische Cycloadditionen, in denen Azoliumdienolat‐Intermediate auftreten.

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Benzene construction via organocatalytic formal [3+3] cycloaddition reaction

Cited by 103 publications

References 67 publications

Recent Advances in Organocatalyst‐Mediated Benzannulation Reactions

Recent Advances in Organocatalyst‐Mediated Benzannulation Reactions

Recent Progress in Transition‐Metal‐Free, Base‐Mediated Benzannulation Reactions for the Synthesis of a Diverse Range of Aromatic and Heteroaromatic Compounds

Katalyse durch N‐heterocyclische Carbene über Azoliumdienolate: eine effiziente Strategie für enantioselektive Funktionalisierungen an entfernten Positionen

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