NHC‐Organocatalysed Hydroacylation of Unactivated or Weakly Activated C−C Multiple Bonds and Ketones

Thalakottukara, Dolly David; Gandhi, Thirumanavelan

doi:10.1002/ajoc.202200080

Cited by 3 publications

(1 citation statement)

References 77 publications

(91 reference statements)

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“…1 For decades, N-heterocyclic carbene (NHC) catalysis has been developed as a powerful methodology for the synthesis of numerous heterocyclic compounds. 2 NHC catalysts can react with aldehydes, esters, anhydrides, acyl halides, and carboxylic acids to form varieties of reactive intermediates, for example, Breslow intermediates, enolates and acylazoliums. 3 In addition, NHC can catalyze the umpolung of Michael acceptors 4 and the aza-Morita–Baylis–Hillman reaction.…”

Section: Introductionmentioning

confidence: 99%

NHC-catalyzed formal [3 + 3] annulations of δ-acetoxy allenoates for the synthesis of 4H-pyran derivatives

Bai¹,

Jin²,

Liu³

et al. 2023

Org. Biomol. Chem.

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Section: Introductionmentioning

confidence: 99%

NHC-catalyzed formal [3 + 3] annulations of δ-acetoxy allenoates for the synthesis of 4H-pyran derivatives

Bai¹,

Jin²,

Liu³

et al. 2023

Org. Biomol. Chem.

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Mesomeric Betaines Based on Adamantylated 1,2,4‐Triazolo[4,3‐a]pyrimidin‐5‐ones: Synthesis, Structure and Conversion into Anionic N‐Heterocyclic Carbenes

Sheina

Шестакова

Деев

et al. 2023

Chemistry An Asian Journal

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The CÀ N coupling of 1,2,4-triazolo[1,5-a]pyrimidin-7-ones with 1-adamantanol/1-bromoadamantane leads to 1,2,4-triazolo[4,3-a]pyrimidinium-5-olates, which are represented as mesomeric betaines (MBs). The formation of MBs involves not only N-alkylation of heterocyclic framework but also the rearrangement leading to a change in the type of fusion between pyrimidine and 1,2,4-triazole fragments. The structures of the obtained products were confirmed by the Xray analysis and measurements of 13 CÀ 13 C (J CC ) coupling constants in the 1D 13 C NMR spectra of selectively 13 C-labeled samples. Treatment of the betaines with lithium bis(trimethylsilyl)amide (LiHMDS) gave anionic carbenes, which were detected by 13 C NMR spectroscopy and were trapped by reactions with phenyl isothiocyanate and sulfur. Density functional theory (DFT) and the quantum theory of atoms in molecules (QTAIM) analyses allowed for an insight into the electronic structure of the obtained betaines and N-heterocyclic carbene derivatives.[a] E.

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An Expeditious Synthesis of Ethyl-2-(4-(arylmethylene)-5-oxo-4,5-dihydroisoxazol-3- yl)acetate Derivatives

Kiyani

Delfani

Zamani

2022

COC

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In this contribution, an operationally simple and efficient synthetic procedure for synthesizing derivatives of 4-(arylmethylene)-5-oxo-4,5-dihydroisoxazol-3-yl)acetate has been developed. This interesting synthetic protocol involves the one-pot cyclocondensation of diethyl 3-oxopentanedioate, aryl or heteroaryl aldehydes, and hydroxylamine hydrochloride catalyzed in an aqueous medium using an azolium salt as a robust organo-catalyst. In this work, for the first time, 1,3-dibenzyl-1H-benzo[d]imidazol-3-ium chloride was used as the catalyst for the synthesis of ethyl-2-(4-(arylmethylene)-5-oxo-4,5-dihydroisoxazol-3-yl)acetate derivatives from the commercially available starting materials. Notably, no by-products were observed during the multicomponent reaction. Optimization studies revealed that 5 mol% of 1,3-dibenzyl-1H-benzo[d]imidazol-3-ium chloride is sufficient to perform the experiment. Furthermore, examining the results of the temperature conditions showed that 70 ºC is the best temperature to carry out the reaction. In an optimization study, H2O was the most effective solvent to perform the three-component cyclization reaction. In this method, using H2O as the environmentally benign and inexpensive reaction medium, so from the point of view of the reaction medium, it can be said that this three-component heterocyclization obeys the principles of green chemistry. This procedure has several advantages, such as good to excellent yields, reasonable reaction times, isolation of heterocyclic products without column chromatography or other chromatographic methods, atom-economy, step-economy, and clean reaction profiles. background: Isoxazole-5(4H)-ones are the significant class of isoxazoles, which are used in nonlinear optical materials, filter dyes, molecular devices, and solar cells. Several structures of isoxazole-5(4H)-ones displayed eye-catching biological properties. On the other hand, azolium salts as important nitrogen-containing heterocycles are quaternary ammonium compounds with acidic hydrogen at 2-position, which are used as precursors for N-heterocyclic carbene (NHC) synthesis and also act as the catalyst in organic reactions. conclusion: This procedure has several further advantages, such as good to excellent yields, reasonable reaction times, isolation of heterocyclic products without column chromatography or other chromatographic methods, atom-economy, step-economy, and clean reaction profiles. other: The heterocyclic products characterized using NMR and elemental analysis.

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NHC‐Organocatalysed Hydroacylation of Unactivated or Weakly Activated C−C Multiple Bonds and Ketones

Cited by 3 publications

References 77 publications

NHC-catalyzed formal [3 + 3] annulations of δ-acetoxy allenoates for the synthesis of 4H-pyran derivatives

NHC-catalyzed formal [3 + 3] annulations of δ-acetoxy allenoates for the synthesis of 4H-pyran derivatives

Mesomeric Betaines Based on Adamantylated 1,2,4‐Triazolo[4,3‐a]pyrimidin‐5‐ones: Synthesis, Structure and Conversion into Anionic N‐Heterocyclic Carbenes

An Expeditious Synthesis of Ethyl-2-(4-(arylmethylene)-5-oxo-4,5-dihydroisoxazol-3- yl)acetate Derivatives

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