Acid‐Catalyzed Intramolecular [2+2] Cycloaddition of Ene‐allenones: Facile Access to Bicyclo[<i>n</i>.2.0] Frameworks

Zhao, Junfeng; Loh, Teck‐Peng

doi:10.1002/anie.200902471

Cited by 53 publications

(21 citation statements)

References 71 publications

(16 reference statements)

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“…As depicted in Figure 2, it seemed plausible that lewis acids could also accelerate the cycloadditions [67][68][69][70][71]. It was envisioned that the interaction of a lewis acid with the electrophilic ketene would effectively lower the energy of the lowest unoccupied molecular orbital and render these adducts quite reactive [71,72].…”

Section: S C H E M E 2 General Route For the Preparation Of Azetidinone Derivativesmentioning

confidence: 99%

Staudinger ketene–imine [2+2] cycloaddition of novel azomethines to synthesize biologically active azetidinone derivatives and their in vitro antimicrobial studies

Kapoor

Rajput

2021

Journal of Heterocyclic Chem

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Since considerable intrigue has been focused on azetidinone (β-lactam) compounds for their wide range antimicrobial activity, the present study focuses on the synthesis of new series of azetidinone compounds. The reaction between the novel azomethine and α-haloester in the presence of Zn impetus and benzene resulted into the formation of desired azetidinone derivative by [2+2] cycloaddition involving imine-ketene. The reaction has also been studied in the presence of diverse Lewis acids such as Zn(OTf) 2 , ZnCl 2 , Cu(OTf) 2 , TiCl 4 , and BF 3 .Et 2 O. The effect of such Lewis acids also enhance the yield of the desired product. Moreover, the structure of the isolated products was also affirmed by spectral analysis (Fourier-transform infrared [FT-IR] spectroscopy, proton nuclear magnetic resonance [ 1 H NMR], carbon-13 nuclear magnetic resonance [ 13 C NMR], and high-resolution mass spectrometry [HRMS]). Furthermore, the antibacterial activity of synthesized compounds has been screened in vitro against different pathogenic bacterial and fungus species.Inspection of the results uncovered that all of the newly synthesized compounds individually display varying degrees of inhibitory impacts on the development of the tested bacterial species, thus, they might be considered as medication possibility for bacterial pathogens. The azomethine exhibited an expansive range of antibacterial activity against Gram-negative Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, and Acinetobacter baumannii and Gram-positive Staphylococcus aureus bacterial strains and antifungal activity against Candida albicans, Candida tropicalis, and Candida parapsilosis bacterial strain. The result demonstrated that the β-lactam subordinates have good antibacterial and antifungal activities on microscopic organisms.

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Section: S C H E M E 2 General Route For the Preparation Of Azetidinone Derivativesmentioning

confidence: 99%

Staudinger ketene–imine [2+2] cycloaddition of novel azomethines to synthesize biologically active azetidinone derivatives and their in vitro antimicrobial studies

Kapoor

Rajput

2021

Journal of Heterocyclic Chem

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“…Unlike other group III elements, such as aluminum and boron, trimethylsilyl halide is often employed together with InX 3 as a robust combined Lewis acid catalyst, as observed in various reactions developed by Baba [ 43 , 44 ], Lee [ 45 ], Corey [ 24 , 46 ], our group [ 47 , 48 , 49 ], and others. As a continuation of our research interest in the application of indium in organic synthesis [ 47 , 48 , 49 , 50 , 51 ], herein we wish to report the first example of the In(III)-TMSBr - catalysed cascade reaction of diarylalkynes with acrylates to access a series of dihydronaphthalene derivatives in a one-pot manner ( Scheme 1 ).…”

Section: Introductionmentioning

confidence: 99%

In(III)-TMSBr-Catalyzed Cascade Reaction of Diarylalkynes with Acrylates for the Synthesis of Aryldihydronaphthalene Derivatives

Zhang

Shen

et al. 2018

Molecules

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A combined Lewis acid system comprising of two or more Lewis acids occasionally exhibits augmented catalytic activity in organic transformations which are otherwise unrealizable by either of the components exclusively. On the other hand, the efficient construction of multiple new C-C bonds and polycyclic structures in minimal steps remains a subject of great interest in both academia and industry. Herein we report an efficient method to assemble aryldihydronaphthalene derivatives via a cascade reaction of diarylalkynes with acrylates under the catalysis of a combined Lewis acid derived from In(III) salt and TMSBr.

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“…1,2-Allenic ketones have become very useful in organic synthesis [ 16 – 33 ]. Current methods for the oxidation of allenic alcohols to ketones include oxidation with MnO 2 [ 30 , 34 – 35 ], Swern oxidation [ 17 , 24 ] or Dess–Martin oxidation [ 16 – 17 24 – 25 28 , 31 – 33 ]: Catalytic aerobic oxidation has not so far been reported. Due to the synthetic potential of 1,2-allenyl ketones, it is desirable to develop an aerobic oxidation protocol for 2,3-allenols.…”

Section: Introductionmentioning

confidence: 99%

CuCl-catalyzed aerobic oxidation of 2,3-allenols to 1,2-allenic ketones with 1:1 combination of phenanthroline and bipyridine as ligands

Gao¹,

Liu²,

Ma³

2011

Beilstein J. Org. Chem.

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SummaryA protocol has been developed to prepare 1,2-allenyl ketones using molecular oxygen in air or pure oxygen as the oxidant from 2,3-allenylic alcohols with moderate to good yields under mild conditions. In this reaction CuCl (20 mol %) with 1,10-phenanthroline (10 mol %) and bipyridine (10 mol %) was used as the catalyst. It is interesting to observe that the use of the mixed ligands is important for the higher yields of this transformation: With the monoligand approach developed by Markó et al., the yields are relatively lower.

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Acid‐Catalyzed Intramolecular [2+2] Cycloaddition of Ene‐allenones: Facile Access to Bicyclo[n.2.0] Frameworks

Cited by 53 publications

References 71 publications

Staudinger ketene–imine [2+2] cycloaddition of novel azomethines to synthesize biologically active azetidinone derivatives and their in vitro antimicrobial studies

Staudinger ketene–imine [2+2] cycloaddition of novel azomethines to synthesize biologically active azetidinone derivatives and their in vitro antimicrobial studies

In(III)-TMSBr-Catalyzed Cascade Reaction of Diarylalkynes with Acrylates for the Synthesis of Aryldihydronaphthalene Derivatives

CuCl-catalyzed aerobic oxidation of 2,3-allenols to 1,2-allenic ketones with 1:1 combination of phenanthroline and bipyridine as ligands

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