Synthesis of aminopyrazoles from sydnones and ynamides

Wezeman, Tim; Comas-Barceló, Júlia; Nieger, Martin; Harrity, Joseph P. A.; Bräse, Stefan

doi:10.1039/c6ob02518h

Cited by 26 publications

(15 citation statements)

References 57 publications

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“…In 2014, Danheiser et al examined the reactivity of N -tosyl-3-azacyclohexyne ( 13-32 ) in the presence of various arynophiles, i.e., tetracyclone, benzyl azide, and Bu 3 SnH, all of which could afford the corresponding products 13-48 in moderate to high yields with excellent regioselectivity (Scheme a) . Subsequently, Bräse and co-workers reported the cycloaddition reactions of compound 13-32 with sydnones 13-49 , furnishing fused amino-substituted pyrazole scaffolds 13-50a and 13-50b (Scheme b) . In 2015, Houk, Garg, and co-workers studied the reactivity of 3,4-piperidyne precursor 13-36 with different arynophiles (Scheme c) .…”

Section: Cyclohexyne 12-cyclohexadiene and 123-cyclohexatrienementioning

confidence: 99%

o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

2021

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Arynes are among the most active organic intermediates and have found numerous applications in expeditious preparation of substituted arenes. In the past 20 years, chemists have witnessed a resurgence in aryne chemistry, which is mainly attributed by the extensive utilization of Kobayashi's method, a fluoride-induced removal of the TMS group with concomitant departure of its ortho OTf group on o-silylaryl triflates. Nowadays, o-silylaryl triflates are the most frequently employed aryne precursors. This review provides an overview of the history of Kobayashi's method, its methodological achievements, and its applications in the synthesis of natural products, bioactive molecules, and polycyclic aromatic hydrocarbons.

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Section: Cyclohexyne 12-cyclohexadiene and 123-cyclohexatrienementioning

confidence: 99%

o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

2021

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“…The in situ generation of arynes or six-membered cycloalkynes from their corresponding trimethylsilyl triflates was recently used by Garg et al [ 115 ] and Bräse et al [ 116 ] in expanding the utility of oxygen- or nitrogen-containing strained heterocycloalkynes ( Scheme 15 ) but the regioselectivity was poor in most cases.…”

Section: Reviewmentioning

confidence: 99%

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

Hladíková¹,

Váňa²,

Hanusek³

2018

Beilstein J. Org. Chem.

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This review covers all known examples of [3 + 2]-cycloaddition between sydnones and both terminal as well as internal alkynes/cycloalkynes taken from literature since its discovery by Huisgen in 1962 up to the current date. Except enumeration of synthetic applications it also covers mechanistic studies, catalysis, effects of substituents and reaction conditions influencing reaction rate and regioselectivity.

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“…fully unsaturated achiral pyrazole derivatives with the use of hydrazones 16,17 and sydnones [40][41][42][43][44][45][46][47] as 1,3-dipoles and even metal-free reactions can be regio-and stereoselective. 7,8,[49][50][51][52] Another difference between the reactions is in the catalyst scope, which is broader with CuAIAC which is catalyzed by Cu(I) and Cu(II), while CuAAC is catalyzed only by Cu(I)-species (cf.…”

Section: Syn Thesismentioning

confidence: 99%

Copper-Catalyzed Azomethine Imine–Alkyne Cycloadditions (CuAIAC)

Grošelj

Požgan²,

Štefane³

et al. 2018

Synthesis

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Although the first example of copper-catalyzed azomethine imine–alkyne cycloaddition (CuAIAC) was published only a year after the seminal papers of Meldal and Sharpless on Cu-catalyzed azide–alkyne cycloaddition (CuAAC), the CuAIAC reaction has remained overlooked by the synthetic community for almost a decade. Since 2010, however, CuAIAC reaction started to emerge as a promising supplement to the well-known CuAAC reaction. The present review surveys primarily the literature on CuAIAC reaction since 2003. Beside this, azomethine imine–alkyne cycloadditions catalyzed by other metals, selected examples of metal-free reactions, and related [3+3] and [3+4] cycloadditions of azomethine imines are presented. All these experimental data indicate the viability of CuAIAC in organic synthesis and the applicability in ‘click’ chemistry.1 Introduction2 Reactions with Acyclic Azomethine Imines3 Reactions with C,N-Cyclic Azomethine Imines4 Reactions with N,N-Cyclic Azomethine Imines5 Reactions with C,N,N-Cyclic Azomethine Imines6 The Mechanism of the CuAIAC Reaction7 Conclusions and Outlook

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Synthesis of aminopyrazoles from sydnones and ynamides

Abstract: Both copper-catalyzed and strain-mediated cycloadditions between ynamides and sydnones allow for a novel synthetic access to aminopyrazoles.

Cited by 26 publications

References 57 publications

o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

Copper-Catalyzed Azomethine Imine–Alkyne Cycloadditions (CuAIAC)

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