Anionic [4+3] heteroannulation of 2-azidoacrylates: a modular synthesis of 2-benzazepin-1-ones

Dinda, Bidyut Kumar; Jana, Amit Kumar; Mal, Dipakranjan

doi:10.1039/c2cc30279a

Cited by 30 publications

(11 citation statements)

References 43 publications

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“…In 2012, Mal reported the synthesis of 2-benzazepin-1ones 2.18c from phthalides 2.18a and 2-azidoacrylates 2.18b using LiHMDS (Scheme 2.18). 40 In almost all cases, the cycloadducts 2.18c were oxidized in the presence of MnO 2 , furnishing the benzazepinediones 2.18d. The oxidized products 2.18d were easier to characterize by 1 H NMR than compounds 2.18c.…”

Section: Special Topic Synthesismentioning

confidence: 99%

Recent Advances in Transition-Metal-Free (4+3)-Annulations

et al. 2021

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Abstract(4+3)-Annulations are incredibly versatile reactions which combine a 4-atom synthon and a 3-atom synthon to form both 7-membered carbocycles as well as heterocycles. We have previously reviewed transition-metal-catalyzed (4+3)-annulations. In this review, we will cover examples involving bases, NHCs, phosphines, Lewis and Brønsted acids as well as some rare examples of boronic acid catalysis and photocatalysis. In analogy to our previous review, we exclude annulations involving cyclic dienes like furan, pyrrole, cyclohexadiene or cyclopentadiene, as Chiu, Harmata, Fernándes and others have recently published reviews encompassing such substrates. We will however discuss the recent additions (2010–2020) to the literature on (4+3)-annulations involving other types of 4-atom-synthons.1 Introduction2 Bases3 Annulations Using N-Heterocyclic Carbenes3.1 N-Heterocyclic Carbenes (NHCs)3.2 N-Heterocyclic Carbenes and Base Dual-Activation4 Phosphines5 Acids5.1 Lewis Acids5.2 Brønsted Acids6 Boronic Acid Catalysis and Photocatalysis7 Conclusion

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Section: Special Topic Synthesismentioning

confidence: 99%

Recent Advances in Transition-Metal-Free (4+3)-Annulations

et al. 2021

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“…21 Quite interestingly, the reactions produced benzazepinones instead of the desired 2-azido-1-naphthols. 22 Alternatively, demethoxycarbonylative annulation with α-acylaminoacrylates for the synthesis of 2-amino-1-naphthols was envisaged, which forms the subject of the present report. Although the reactivities of amidoacrylates are well established, their annulation behavior is less explored.…”

Section: Syn Thesismentioning

confidence: 99%

A Five-Step Cascade for the Modular and Regiodefined Synthesis of Naphth[2,1-d]oxazoles

et al. 2016

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The reaction of 3-nucleofugal phthalides with 2-amidoacrylates is shown to provide a synthesis of densely substituted naphth[2,1d]oxazoles in good yields. It is proposed to proceed via a five-step cascade which includes phthalide annulation, demethoxycarbonylation, and heterocyclization. The methodology is free from regiochemical ambiguity of the products. In certain cases, the corresponding 2-amidonaphthoquinones are directly formed.

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“…49 The proposed mechanism involved Michael addition of the benzylic anion 186 to the C=C bond of vinyl azide 33 , creating the new anion species 188 . Loss of dinitrogen gave rise to iminyl anion 189 , which underwent an intramolecular nucleophilic addition to the lactone carbonyl to generate 7-membered lactam 191 (path a).…”

Section: Base-mediated Reactions Of Vinyl Azidesmentioning

confidence: 99%

Reactivities of vinyl azides and their recent applications in nitrogen heterocycle synthesis

DiMagno

2015

Org. Biomol. Chem.

183

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Nitrogen heterocycles are abundant in natural products and pharmaceuticals. An emerging interest among synthetic chemists is to apply vinyl azides as a pivotal three-atom synthon for the construction of structurally complex and diverse N-heterocyclic skeletons. The unique features of the azide group connected to an alkene moiety permit vinyl azides to function as electrophiles, nucleophiles, or radical acceptors; their access to diverse reaction pathways provides great opportunities to generate highly reactive intermediates with often unusual or unconventional reactivities. This tutorial review will systematically illustrate the reactivities of vinyl azides and describe recent breakthroughs in the development of new transformations that create N-heterocycles.

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Anionic [4+3] heteroannulation of 2-azidoacrylates: a modular synthesis of 2-benzazepin-1-ones

Abstract: 2-Azidoacrylates undergo [4+3] annulation with phthalides under anionic conditions at low temperatures to furnish 5-hydroxy-2-benzazepinones, the formation of which represents a new concept for the construction of azepines as well as a new reactivity of 2-azidoacrylates.

Cited by 30 publications

References 43 publications

Recent Advances in Transition-Metal-Free (4+3)-Annulations

Recent Advances in Transition-Metal-Free (4+3)-Annulations

A Five-Step Cascade for the Modular and Regiodefined Synthesis of Naphth[2,1-d]oxazoles

Reactivities of vinyl azides and their recent applications in nitrogen heterocycle synthesis

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