[5 + 2] Cycloaddition Reaction of 2-Vinylaziridines and Sulfonyl Isocyanates. Synthesis of Seven-Membered Cyclic Ureas

Kanno, Eri; Yamanoi, Kenichi; Koya, Shunsuke; Azumaya, Isao; Masu, Hyuma; Yamasaki, Ryu; Saito, Shinichi

doi:10.1021/jo201959a

Cited by 35 publications

(8 citation statements)

References 26 publications

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“…For instance, the reaction of these substrates with electron‐poor alkynes leads to a seven‐membered ring through a divinylcyclopropane–cycloheptadiene‐type rearrangement 6. Moreover, phenyl isothiocyanate and very recently sulfonyl isocyanates have been employed as C2 units in formal [5+2] cycloaddition reactions with 2‐vinylaziridines to smoothly produce 1,3‐thiazepine derivates7 and various cyclic ureas,8 respectively (Scheme a and b). It is remarkable that in these cases the cycloaddition processes occurred at 0 °C and in the absence of metal catalysts.…”

Section: Introductionmentioning

confidence: 99%

The Photochemical Reaction of Vinylaziridines and Vinylazetidines with Chromium(0) and Molybdenum(0) (Fischer) Carbene Complexes

Rivero

Fernández

Sierra

2013

Chemistry A European J

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The [5+2] and [6+2] cycloaddition reactions of vinylaziridines and vinylazetidines with ketenes generated photochemically from chromium(0) and molybdenum(0) Fischer carbene complexes have been investigated. These processes constitute a straightforward and efficient route to azepanones and azocinones, respectively. The peculiar electronic properties of the metalated ketenes allow for the introduction of electron-rich substituents in the final cycloadducts, a difficult task using conventional organic chemistry procedures. The versatility of the process is demonstrated by using Cr(0) Fischer bis(carbene) complexes as metalated bis(ketene) precursors. These species produce tethered bis(azepanone)s in a single step under mild reaction conditions. Density functional theory calculations point to a stepwise reaction pathway through the initial nucleophilic attack of the nitrogen atom of the aziridine on the metalated ketene, followed by ring closure of the zwitterionic intermediate formed.

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Section: Introductionmentioning

confidence: 99%

The Photochemical Reaction of Vinylaziridines and Vinylazetidines with Chromium(0) and Molybdenum(0) (Fischer) Carbene Complexes

Rivero

Fernández

Sierra

2013

Chemistry A European J

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“…13 Of the two possible mechanisms, the first involved an initial cleavage of aziridine ring by alkyl amines at C . 150 It is worth mentioning that the reaction did not require any catalyst. The reaction was, however, extremely sensitive to solvents.…”

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confidence: 99%

Recent applications of aziridine ring expansion reactions in heterocyclic synthesis

Singh¹,

Sudheesh²,

Keroletswe³

2017

Arkivoc

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The inherent reactivity of the aziridine ring due to ring-strain makes it valuable building blocks for the synthesis of other heterocyclic motifs of biological relevance. Of particular significance is the generation of azomethine ylides from them and cycloaddition of ylides with alkenes, alkynes, and heterocumulenes. The ring undergoes opening followed by cyclization with a variety of reagents either in the presence of a catalyst or without any catalyst. This review article discusses the recent applications of aziridines in syntheses of four-to seven-membered heterocycles of biological relevance such as azetidines, 2

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“…In order to close this section, a recent report from Saito et al [49] deserves to be presented. We previously mentioned the thermal reaction of phenyl isocyanate with 2-alkenyl aziridines (Scheme 8), which is not selective.…”

Section: Expansions Into Six-and Seven-membered Ringsmentioning

confidence: 99%

Ring Expansions of Nonactivated Aziridines and Azetidines

Couty

David

2015

Topics in Heterocyclic Chemistry

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Ring expansions promoted by ring strain in aziridines and azetidines are reviewed in this chapter, putting emphasis on recent applications from the last decade. This vast subject cannot be surveyed here exhaustively, and the reader will be guided to relevant precedent reviews or key reports. Rather, special attention will be put on selected examples and their mechanistic details, aiming to demonstrate that high selectivity can be reached in these reactions. In this issue, this fastgrowing topic has been divided into two distinct chapters, this one dealing with "nonactivated" aziridines and azetidines. Therefore, the reader will only find here examples involving NH-or N-alkylaziridines and N-azetidines as substrates for ring expansions, while N-acyl, N-carbamoyl, or N-tosyl compounds, defined as "activated" substrates, will be presented in the next chapter. This distinction can appear quite arbitrary at first sight but is amply justified by the great difference in reactivity of these distinct substrates. The first part focuses on the ring expansions of nonactivated aziridines into up to seven-membered rings and is further divided into expansions involving the incorporation of one (or more) heteroatoms, followed by ring expansions involving only incorporation of carbon atoms. The same model is then followed for azetidines.

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[5 + 2] Cycloaddition Reaction of 2-Vinylaziridines and Sulfonyl Isocyanates. Synthesis of Seven-Membered Cyclic Ureas

Cited by 35 publications

References 26 publications

The Photochemical Reaction of Vinylaziridines and Vinylazetidines with Chromium(0) and Molybdenum(0) (Fischer) Carbene Complexes

The Photochemical Reaction of Vinylaziridines and Vinylazetidines with Chromium(0) and Molybdenum(0) (Fischer) Carbene Complexes

Recent applications of aziridine ring expansion reactions in heterocyclic synthesis

Ring Expansions of Nonactivated Aziridines and Azetidines

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