Ruthenium(II)‐Catalyzed Synthesis of Pyrrole‐ and Indole‐Fused Isocoumarins by C−H Bond Activation in DMF and Water

Singh, Keisham S.; Sawant, Sneha G.; Dixneuf, Pierre H.

doi:10.1002/cctc.201501261

Cited by 59 publications

(29 citation statements)

References 83 publications

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“…Additionally, the synthesis of 2 was investigated in an aprotic solvent 1,4‐dioxane, which is the solvent of choice in the arylation of phenylpyrimidines catalyzed by [RuCl 2 ( p ‐cymene)] 2 /carboxylate . If 1 b was reacted with 0.5 equivalents of [RuCl 2 ( p ‐cymene)] 2 and 2 equivalents of KOAc in 1,4‐dioxane at room temperature, the quantitative conversion of 1 b to a 1.3:1 mixture of 2 e and 2 b was reached in 24 h. This observation is different from previous descriptions of the cyclometallation of arylimines with [RuCl 2 ( p ‐cymene)] 2 in which the solvent MeOH and 4 equivalents of KOAc were crucial for the reaction to occur…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Reactivity of 2‐Arylquinazoline Halidoruthenacycles in Arylation Reactions

et al. 2017

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The synthesis of a range of new cyclometallated organoruthenium(II) complexes through the ortho‐C−H activation of the aryl group in 2‐aryl‐substituted quinazolines with [RuX2(p‐cymene)]2 is described. The beneficial effect of the carboxylate ligand on both the cyclometallation and the further arylation reaction step was demonstrated. Mechanistic studies reveal that bromide and iodide anions decelerate the arylation process by an in situ ligand exchange reaction. Additionally, a detailed NMR spectroscopy investigation was performed to explain some elementary steps in the arylation of 2‐(aryl)quinazoline halidoruthenacycles.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Reactivity of 2‐Arylquinazoline Halidoruthenacycles in Arylation Reactions

et al. 2017

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“…Recently, Singh and Dixneuf described the ruthenium-catalysed annulation of pyrrole and indole carboxylic acid derivatives with alkynes, leading to pyrrole and indole-fused isocoumarins (Scheme 85) [171]. The reaction was performed using [RuCl 2 (p-cymene)] 2 in the presence of Cu(OAc) 2 •H 2 O but without an additive in DMF.…”

Section: Ruthenium-catalysed Annulation Reaction Of Arenes With Alkynesmentioning

confidence: 99%

Recent Advances in C–H Bond Functionalization with Ruthenium-Based Catalysts

Singh

2019

Catalysts

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The past decades have witnessed rapid development in organic synthesis via catalysis, particularly the reactions through C–H bond functionalization. Transition metals such as Pd, Rh and Ru constitute a crucial catalyst in these C–H bond functionalization reactions. This process is highly attractive not only because it saves reaction time and reduces waste,but also, more importantly, it allows the reaction to be performed in a highly region specific manner. Indeed, several organic compounds could be readily accessed via C–H bond functionalization with transition metals. In the recent past, tremendous progress has been made on C–H bond functionalization via ruthenium catalysis, including less expensive but more stable ruthenium(II) catalysts. The ruthenium-catalysed C–H bond functionalization, viz. arylation, alkenylation, annulation, oxygenation, and halogenation involving C–C, C–O, C–N, and C–X bond forming reactions, has been described and presented in numerous reviews. This review discusses the recent development of C–H bond functionalization with various ruthenium-based catalysts. The first section of the review presents arylation reactions covering arylation directed by N–Heteroaryl groups, oxidative arylation, dehydrative arylation and arylation involving decarboxylative and sp3-C–H bond functionalization. Subsequently, the ruthenium-catalysed alkenylation, alkylation, allylation including oxidative alkenylation and meta-selective C–H bond alkylation has been presented. Finally, the oxidative annulation of various arenes with alkynes involving C–H/O–H or C–H/N–H bond cleavage reactions has been discussed.

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“…Hydroindolation of N ‐methylindolecarboxylic acid with internal alkynes in the presence of a Ru II catalyst occurs with the active partecipation of the carboxylic group leading to indole‐fused isocoumarins (Scheme ) . As already observed in similar alkenylations using olefins a cyclometalated ruthenium salt is a probable intermediate in the mechanism leading to the final products.…”

Section: Hydroindolation Of Alkynes and Allenesmentioning

confidence: 99%

Regioselective Direct C‐Alkenylation of Indoles

Petrini

2017

Chemistry A European J

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The direct introduction of alkenyl groups into the indole framework avoiding its preliminary functionalization can be carried out using different synthetic strategies. Transition-metal complexes facilitate the C-H activation of indoles or alkenes allowing an efficient Csp - Csp bond formation. The hydroindolation of alkynes catalyzed by the same metal complexes or various acidic promoters can also be pursued for the alkenylation process. Conjugate addition of electron-poor alkenes and direct condensation of carbonyl derivatives with indoles are also of interest for this purpose. The regiochemical control can be exploited using the intrinsic C-3 reactivity of the indole ring. The introduction of a suitable directing group at the nitrogen atom allows the preparation of C-2 alkenylated derivatives by transition metal catalyzed reactions. This review collects the fundamental contributions in this field reported in literature during the last fifteen years.

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Ruthenium(II)‐Catalyzed Synthesis of Pyrrole‐ and Indole‐Fused Isocoumarins by C−H Bond Activation in DMF and Water

Abstract: International audienceno abstrac

Cited by 59 publications

References 83 publications

Synthesis and Reactivity of 2‐Arylquinazoline Halidoruthenacycles in Arylation Reactions

Synthesis and Reactivity of 2‐Arylquinazoline Halidoruthenacycles in Arylation Reactions

Recent Advances in C–H Bond Functionalization with Ruthenium-Based Catalysts

Regioselective Direct C‐Alkenylation of Indoles

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