Transition Metal‐Catalyzed Synthesis of Fused Five‐Membered Aromatic Heterocycles

Dudnik, Alexander S.; Gevorgyan, Vladimir

doi:10.1002/9783527633388.ch9

Cited by 8 publications

(7 citation statements)

References 290 publications

(246 reference statements)

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“…In connection with this work, we switched our attention to the formation of carbon–heteroatom bonds using indium catalysis, in particular to the indium(III)-catalyzed intramolecular hydroalkoxylation of o -alkynylphenols for the synthesis of benzo[ b ]furans (Scheme b). The benzofuran ring is a privileged structure that is present in a large number of biologically active compounds and natural products, and the development of practical, green, and economical methods for synthesis of this unit has been widely pursued . One of the most straightforward approaches to benzofurans involves the hydroalkoxylation reaction of o -alkynylphenols using catalysis with precious transition metals such as palladium, platinum, rhodium, or gold .…”

Section: Introductionmentioning

confidence: 99%

Indium(III)-Catalyzed Synthesis of Benzo[b]furans by Intramolecular Hydroalkoxylation of ortho-Alkynylphenols: Scope and Mechanistic Insights

et al. 2018

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Indium(III) halides catalyze the hydroalkoxylation reaction of ortho-alkynylphenols to afford benzo[ b]furans in good yields. The reaction proceeds with 5- endo- dig regioselectivity with a variety of phenols functionalized at the arene and alkyne moieties in high yields using InI (5 mol %) in DCE. Experimental and computational studies support a mechanism based on the indium(III) π-Lewis acid activation of the alkyne followed by nucleophilic addition of the phenol and final protodemetalation to afford the corresponding benzo[ b]furan. DFT calculations suggest that dimer InI is the catalytic species through a novel double coordination with the alkyne and the hydroxyl group.

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Section: Introductionmentioning

confidence: 99%

Indium(III)-Catalyzed Synthesis of Benzo[b]furans by Intramolecular Hydroalkoxylation of ortho-Alkynylphenols: Scope and Mechanistic Insights

et al. 2018

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“…Several review articles and books have been published that summarize previous and recent developments in this area. 3 In 1996, Cacchi and co-workers reported that 2-(1-alkynyl)phenols in the presence of vinylic triflates and a palladium catalyst undergo cyclization to the corresponding 2,3-disubstituted benzo[ b ]furans. 4 The authors proposed that this process most likely proceeds through a vinylic palladium intermediate, generated in situ from the vinylic triflate via oxidative addition to Pd(0).…”

Section: Introductionmentioning

confidence: 99%

Efficient microwave-assisted one-pot three-component synthesis of 2,3-disubstituted benzofurans under Sonogashira conditions

2013

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An efficient one-pot method for the synthesis of 2,3-disubstituted benzo[b]furans from commercially available 2-iodophenols, terminal acetylenes and aryl iodides has been developed utilizing Sonogashira reaction conditions. After an initial Sonogashira coupling of the 2-iodophenol with the terminal alkyne, cyclization involving the aryl iodide provides the 2,3-disubstituted benzo[b]furan in good to excellent yields. The use of microwave irradiation shortens the reaction times and minimizes the side products. This methodology is especially useful for the construction of libraries of highly substituted benzo[b]furans and their analogues.

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“…The synthesis of these important molecules can be achieved by construction of one or both rings, or via direct functionalization of the benzothiophene core91011. Due to the ubiquity of C–H bonds, the most efficient methods of C–C bond construction are based on C–H functionalization1213.…”

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confidence: 99%

Regioselective synthesis of C3 alkylated and arylated benzothiophenes

et al. 2017

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Benzothiophenes are heterocyclic constituents of important molecules relevant to society, including those with the potential to meet modern medical challenges. The construction of molecules would be vastly more efficient if carbon–hydrogen bonds, found in all organic molecules, can be directly converted into carbon–carbon bonds. In the case of elaborating benzothiophenes, functionalization of carbon–hydrogen bonds at carbon-number 3 (C3) is markedly more demanding than at C2 due to issues of regioselectivity (C3 versus C2), and the requirement of high temperatures, precious metals and the installation of superfluous directing groups. Herein, we demonstrate that synthetically unexplored but readily accessible benzothiophene S-oxides serve as novel precursors for C3-functionalized benzothiophenes. Employing an interrupted Pummerer reaction to capture and then deliver phenol and silane coupling partners, we have discovered a directing group-free method that delivers C3-arylated and -alkylated benzothiophenes with complete regioselectivity, under metal-free and mild conditions.

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Transition Metal‐Catalyzed Synthesis of Fused Five‐Membered Aromatic Heterocycles

Cited by 8 publications

References 290 publications

Indium(III)-Catalyzed Synthesis of Benzo[b]furans by Intramolecular Hydroalkoxylation of ortho-Alkynylphenols: Scope and Mechanistic Insights

Indium(III)-Catalyzed Synthesis of Benzo[b]furans by Intramolecular Hydroalkoxylation of ortho-Alkynylphenols: Scope and Mechanistic Insights

Efficient microwave-assisted one-pot three-component synthesis of 2,3-disubstituted benzofurans under Sonogashira conditions

Regioselective synthesis of C3 alkylated and arylated benzothiophenes

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