Cu 0 -catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N -cyclic azomethine imines to ynones

Mirnik, Jona; Kirar, Eva Pušavec; Ričko, Sebastijan; Grošelj, Uroš; Golobič, Amalija; Požgan, Franc; Štefane, Bogdan; Svete, Jurij

doi:10.1016/j.tet.2017.04.050

Cited by 11 publications

(7 citation statements)

References 40 publications

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“…The highest conversions (95–100%) were obtained with 3,4,5-trimethoxyphenyl- ( 6a ), phenyl- ( 6d ), and 4-nitrophenyl-substituted dipole ( 6f ), whereas poor conversions (23–29%) were observed with 4-methoxy- ( 6b ), 4-methyl- ( 6c ), and 4-chloro-substituted dipole ( 6e ). Since closely related Cu 0 - and Cu + -catalyzed cycloadditions did not show any significant substrate dependence [ 56 , 57 ], incomplete conversions may seem surprising, yet they are explainable by much shorter reaction time (i.e., 12–48 h [ 56 , 57 ] vs. 3 h in the present case). Quantitative conversion of dipole 6e into cycloadduct 8e after 48 h was in line with this rationale ( Scheme 2 ).…”

Section: Resultsmentioning

confidence: 65%

“…In recent years, an important part of our ongoing research on the chemistry of 3-pyrazolidinones [ 55 ] has been focused on CuAIAC reactions catalyzed by Cu(0) [ 56 , 57 ], Cu(I) [ 58 , 59 , 60 , 61 ], and Cu(II) [ 27 ]. In extension, we were interested in the use of immobilized Cu(II) complexes with enaminone-type ligands attached to the solid support in CuAIAC reactions.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of 6,7-Dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles by Azomethine Imine-Alkyne Cycloadditions Using Immobilized Cu(II)-Catalysts

et al. 2021

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A series of 12 silica gel-bound enaminones and their Cu(II) complexes were prepared and tested for their suitability as heterogeneous catalysts in azomethine imine-alkyne cycloadditions (CuAIAC). Immobilized Cu(II)–enaminone complexes showed promising catalytic activity in the CuAIAC reaction, but these new catalysts suffered from poor reusability. This was not due to the decoordination of copper ions, as the use of enaminone ligands with additional complexation sites resulted in negligible improvement. On the other hand, reusability was improved by the use of 4-aminobenzoic acid linker, attached to 3-aminopropyl silica gel via an amide bond to the enaminone over the more hydrolytically stable N-arylenamine C-N bond. The study showed that silica gel-bound Cu(II)–enaminone complexes are readily available and suitable heterogeneous catalysts for the synthesis of 6,7-dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles.

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Section: Resultsmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Synthesis of 6,7-Dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles by Azomethine Imine-Alkyne Cycloadditions Using Immobilized Cu(II)-Catalysts

et al. 2021

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“…An example of a reaction between an azomethine imine 92 and an allene derivative to afford the 3pyrazoline 93 is presented in Scheme 25. 97,101 Scheme 25. Synthesis of 3-pyrazoline 93 from azomethine imine 92.…”

Section: © Author(s)mentioning

confidence: 99%

3-Pyrazolines (2,3-dihydro-1H-pyrazoles): synthesis, reactivity, and physical and biological properties

Hoz¹,

Claramunt²,

Elguero³

et al. 2021

Arkivoc

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“…were in line with broad substrate tolerance including otherwise less reactive 4-acylamino-substituted dipoles 57 (Scheme 23). 39 Scheme 23 Reagents and conditions: (i) 57 (1.0 equiv), 7 (1.2 equiv), Cu powder, CH 2 Cl 2 , r.t., 16 h. Mixtures of non-racemic diastereomers 76/77 were obtained by a one-pot procedure from the pyrazolidinone 72 and aromatic aldehydes to give dipoles 53, followed by a treatment with chiral non-racemic ynone 75. Upon prolonged reaction time without strict exclusion of air and moisture the primary product 76/77 was partially converted into 3-(pyrazol-1-yl)-3-methylbutanoic acid 78.…”

Section: Review Syn Thesismentioning

confidence: 99%

“…11b This definition is easily extendable to CuAIAC as well. However, the fact that stereochemistry in thermal-and in Cucatalyzed reactions is the same, 28,39 suggests that concertedness is mostly preserved also in the Cu-catalyzed cycloadditions. Presumably the most appropriate mechanistic definition of CuAIAC would be, that CuAIAC is an asynchronous, but still concerted [3+2]-cycloaddition reaction.…”

Section: The Mechanism Of the Cuaiac Reactionmentioning

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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Cu 0 -catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N -cyclic azomethine imines to ynones

Cited by 11 publications

References 40 publications

Synthesis of 6,7-Dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles by Azomethine Imine-Alkyne Cycloadditions Using Immobilized Cu(II)-Catalysts

Synthesis of 6,7-Dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles by Azomethine Imine-Alkyne Cycloadditions Using Immobilized Cu(II)-Catalysts

3-Pyrazolines (2,3-dihydro-1H-pyrazoles): synthesis, reactivity, and physical and biological properties

Copper-Catalyzed Azomethine Imine–Alkyne Cycloadditions (CuAIAC)

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