PEG3400–Cu2O–Cs2CO3: an efficient and recyclable microwave-enhanced catalytic system for ligand-free Ullmann arylation of indole and benzimidazole

Colacino, Evelina; Villebrun, Laurent; Martinez, Jean; Lamaty, Frédéric

doi:10.1016/j.tet.2010.03.065

Cited by 62 publications

(21 citation statements)

References 45 publications

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“…Alteration of the molar ratio of imidazole to iodobenzene (entries [13][14] or decreasing the amount of the base (entry 15) only led to lower yields of the product. Replacing NaOH with other bases such as K 3 PO 4 or Cs 2 CO 3 , which are more common in Cucatalyzed reactions, did not improve the results (entries [16][17]. We next studied the generality of the procedure by applying the optimized conditions (Table 1, entry 10 for ArI and entry 11 for ArBr) to the reactions of some other nitrogen-heterocycles with di erent aryl halides.…”

Section: Resultsmentioning

confidence: 99%

“…For instance, Huang reported amination of aryl iodides and bromides with aqueous ammonia using CuSO 4 , Cs 2 CO 3 , and sucrose as the ligand in PEG-200/water (1:1) [16]. Colasino and coworkers reported N-arylation of indole and benzimidazole in PEG-3400 under microwave irradiation at 150 C. They used 10 mol% of nano-sized Cu 2 O and two equivalents of Cs 2 CO 3 as the base [17]. N-arylation of indoles has also been performed in glycerol at 120 C using CuI (10 mol%) and DMSO [18].…”

Section: Introductionmentioning

confidence: 99%

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Copper-catalyzed N-arylation of heterocycles in ethylene glycol medium

et al. 2016

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N-arylation of imidazole, benzimidazole, pyrazole, and indole was performed in the presence of CuI as the catalyst and NaOH as the base in ethylene glycol medium. Apparently, ethylene glycol played a dual role as both the reaction solvent and a ligand for the catalyst. All reactions proceed selectively to give the corresponding N-arylated products. In some cases, O-alkylation or dehalogenation was observed, which was explained by the proposed catalytic cycle. Conventional heating at 120 C and microwave irradiation both were used, where the results showed that microwave irradiation could facilitate the reaction by lowering the reaction times and increasing the yields. The reaction medium was recovered and reused in several consecutive runs.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Copper-catalyzed N-arylation of heterocycles in ethylene glycol medium

et al. 2016

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“…One of the interesting examples was reported by Choudary et al, [100] in which the supported copper fluoroapatite Copper (I) oxide in PEG support were also efficiently used as a recyclable catalyst for the C-N cross-coupling reactions. Lamaty et al [102] reported microwave assisted Cu 2 O-PEG for the coupling between benzimidazoles and indoles with aryl halides (Scheme 32).…”

Section: Scheme 25: Cumentioning

confidence: 99%

Cu/Fe-Catalyzed Carbon-Carbon and Carbon-Heteroatom Cross-Coupling Reactions

Panda¹

2014

Organic Chem Curr Res

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Copper and iron salts are less toxic and inexpensive as compared to other transition metal salts. These salts have been extensively used for various carbon-carbon and carbon-heteroatom cross-coupling reactions. In this review, we described the Cu and Fe-mediated CC , C-N, CO , C-S and C-Se coupling reactions extensively. The synergistic effects of copper and iron salts towards the various bond-forming reactions have been presented. Use of such methods in the synthesis of bioactive molecules were also highlighted.

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“…Recently, Lamaty and co-workers described the use of PEG 3400 -Cu 2 O/Cs 2 CO 3 as an efficient and recyclable catalytic system for the selective N -arylation of N-heterocycles, under microwave irradiation [ 61 ]. Applied to indole, the procedure gave good to high isolated yields ( i.e.…”

Section: Selective Transformation Of Pre-existing N-containing Hetmentioning

confidence: 99%

Recent Advances in the Synthesis of N-Containing Heteroaromatics via Heterogeneously Transition Metal Catalysed Cross-Coupling Reactions

2011

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N-containing heteroaromatics are important substructures found in numerous natural or synthetic alkaloids. The diversity of the structures encountered, as well as their biological and pharmaceutical relevance, have motivated research aimed at the development of new economical, efficient and selective synthetic strategies to access these compounds. Over more than 100 years of research, this hot topic has resulted in numerous so-called “classical synthetic methods” that have really contributed to this important area. However, when the selective synthesis of highly functional heteroaromatics like indoles, quinolones, indoxyls, etc. is considered these methods remain limited. Recently transition metal-catalysed (TM-catalysed) procedures for the synthesis of such compounds and further transformations, have been developed providing increased tolerance toward functional groups and leading generally to higher reaction yields. Many of these methods have proven to be the most powerful and are currently applied in target- or diversity-oriented syntheses. This review article aims at reporting the recent developments devoted to this important area, focusing on the use of heterogeneous catalysed procedures that include either the formation of the heterocyclic ring towards the nuclei or their transformations to highly substituted compounds.

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PEG3400–Cu2O–Cs2CO3: an efficient and recyclable microwave-enhanced catalytic system for ligand-free Ullmann arylation of indole and benzimidazole

Cited by 62 publications

References 45 publications

Copper-catalyzed N-arylation of heterocycles in ethylene glycol medium

Copper-catalyzed N-arylation of heterocycles in ethylene glycol medium

Cu/Fe-Catalyzed Carbon-Carbon and Carbon-Heteroatom Cross-Coupling Reactions

Recent Advances in the Synthesis of N-Containing Heteroaromatics via Heterogeneously Transition Metal Catalysed Cross-Coupling Reactions

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