Cerium(<scp>III</scp>) Triflate versus Cerium(<scp>III</scp>) Chloride: Anion Dependence of Lewis Acid Behavior in the Deprotection of PMB Ethers

Bartoli, Giuseppe; Dalpozzo, Renato; Nino, Antonio De; Maiuolo, Loredana; Nardi, Mónica; Procopio, Antonio; Tagarelli, Antonio

doi:10.1002/ejoc.200400039

Cited by 35 publications

(11 citation statements)

References 17 publications

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“…The role of ceriumA C H T U N G T R E N N U N G (III) chloride as a Lewis acid catalyst in organic reactions is well documented. [69,70,71] However, as we have observed in this study, CeCl 3 ·7 H 2 O does not act as an ordinary Lewis acid for the activation of H 2 O 2 . In order to show this difference, we have studied the iodination of 1, 3-dimethoxybenzene (1 mmol) using H 2 O 2 (1 mmol) and NaI (1 mmol) in the presence of a catalytic amount of various Lewis acids (0.5 mmol) at room temperature for 1 h. Analysis of the reaction mixtures showed the formation of the mono-iodinated product from a trace to a maximum of 20% plus unreacted starting materials (Table 4, entries 2-11).…”

Section: Resultsmentioning

confidence: 44%

Highly Efficient Halogenation of Organic Compounds with Halides Catalyzed by Cerium(III) Chloride Heptahydrate Using Hydrogen Peroxide as the Terminal Oxidant in Water

et al. 2009

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In this article a new environmentally friendly catalytic method is described for the efficient monoiodination and bromination of arenes and also iodoetherification and iodolactonization of olefins using hydrogen peroxide as the terminal oxidant. The method is based on using sodium iodide or sodium bromide, hydrogen peroxide (35%) and ceriumA C H T U N G T R E N N U N G (III) chloride as an effective catalyst in water at room temperature or under reflux conditions. By this protocol, iodination of anilines proceeded with high regioselectivity at the para position with the formation of small amounts of the ortho isomers. However, bromination of anilines proceeded with absolute regioselectivity to give the para isomers as the sole products in high yields. Iodinations and brominations of m-xylene, toluene, chloro-and bromobenzenes were proceeded with excellent regioselectivity to produce the para isomers as the sole products. Benzene was also halogenated by this catalytic system to give the monohalogenated benzene in good yields. Iodoetherification and iodolactonization of olefins also proceeded easily in high yields at room temperature. However, the bromination of olefins by this protocol failed and the starting materials were detected intact.

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Section: Resultsmentioning

confidence: 44%

Highly Efficient Halogenation of Organic Compounds with Halides Catalyzed by Cerium(III) Chloride Heptahydrate Using Hydrogen Peroxide as the Terminal Oxidant in Water

et al. 2009

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“…Among them, cerium salts have been widely applied in various organic synthetic reactions [39][40][41][42][43]. Our findings indicate that cerium(III) sulphate is an efficient catalyst for our synthesis and allows condensation reactions to occur under very mild conditions with generally short reaction times and good yields.…”

Section: Introductionmentioning

confidence: 68%

Eco-friendly one-pot, three-component synthesis of novel derivatives of kojic acid by the Mannich-type reaction under solvent-free ball-milling conditions

Teimuri‐Mofrad

Shahrisa

Gholamhosseini-Nazari

et al. 2015

Res Chem Intermed

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A novel series of aminokojic acid derivatives were efficiently synthesized by one-pot condensation of kojic acid, aromatic aldehydes and heteroaromatic amines in the presence of cerium(III) sulphate as an efficient and recyclable catalyst in ball-milling under solvent-free conditions at room temperature. This synthesis method offers several advantages, including a green and eco-friendly protocol, operational simplicity, mild reaction conditions, short reaction time, higher yields and easy workup procedures. The workup of these very clean reactions involves only a simple washing with acetone/cold water. The catalytic system can be reused several times with no loss of activity. Graphical Abstract O HO

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“…If the mixture reaction was performed using only 0.5% Er(OTf) 3 we did not observe the complete conversion of amine after 7 min ( Table 1 , entry 11). Considering our experience in the use of lanthanide triflates and, in particular, of Er (III) and Ce (III) [ 70 ], using Ce(OTf) 3 in the same molar percentage (1% mol), the reaction showed the complete conversion of amine after 7 min. Considering the higher cost of Ce (OTf) 3 compared to Er (OTf) 3 , we continued with the synthesis of different disubstituted benzimidazoles using only 1% of Er (III) under MW irradiation.…”

Section: Resultsmentioning

confidence: 99%

The Highly Efficient Synthesis of 1,2-Disubstituted Benzimidazoles Using Microwave Irradiation

et al. 2022

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The benzimidazole ring of the heterocyclic pharmacophores is one of the most widespread and studied systems in nature. The benzimidazole derivative synthesis study is a crucial point for the development of a clinically available benzimidazole-based drug. Here, we report a simple microwave assisted method for the synthesis of 1,2-disubstituted benzimidazoles. The combination of the molar ratio of N-phenyl-o-phenylenediamine:benzaldehyde (1:1) using microwave irradiation and only 1% mol of Er(OTf)3 provides an efficient and environmental mild access to a diversity of benzimidazoles under solvent-free conditions. The proposed method allows for the obtainment of the desired products in a short time and with very high selectivity.

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Cerium(III) Triflate versus Cerium(III) Chloride: Anion Dependence of Lewis Acid Behavior in the Deprotection of PMB Ethers

Cited by 35 publications

References 17 publications

Highly Efficient Halogenation of Organic Compounds with Halides Catalyzed by Cerium(III) Chloride Heptahydrate Using Hydrogen Peroxide as the Terminal Oxidant in Water

Highly Efficient Halogenation of Organic Compounds with Halides Catalyzed by Cerium(III) Chloride Heptahydrate Using Hydrogen Peroxide as the Terminal Oxidant in Water

Eco-friendly one-pot, three-component synthesis of novel derivatives of kojic acid by the Mannich-type reaction under solvent-free ball-milling conditions

The Highly Efficient Synthesis of 1,2-Disubstituted Benzimidazoles Using Microwave Irradiation

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