Furo[3,2-b]pyridine: a convenient unit for the synthesis of polyheterocycles

Chartoire, Anthony; Comoy, Corinne; Fort, Yves

doi:10.1016/j.tet.2008.09.008

Cited by 39 publications

(17 citation statements)

References 46 publications

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“…General Procedure for the One‐pot Synthesis of Derivatives 3a–3g: To a solution of 2‐chlorofuro[3,2‐ b ]pyridine ( 1 )6b (123 mg, 0.80 mmol, 1.0 equiv.) in THF (10 mL) was added dropwise n BuLi (0.6 mL, 0.96 mmol, 1.2 equiv.)…”

Section: Methodsmentioning

confidence: 99%

Resolving the Differences Between the 1.9 Å and 1.95 Å Crystal Structures of Photosystem II: A Single Proton Relocation Defines Two Tautomeric Forms of the Water‐Oxidizing Complex

2015

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Great progress has been made in characterizing the water‐oxidizing complex (WOC) in photosystem II (PSII) with the publication of a 1.9 Å resolution X‐ray diffraction (XRD) and recently a 1.95 Å X‐ray free‐electron laser (XFEL) structure. However, these achievements are under threat because of perceived conflicts with other experimental data. For the earlier 1.9 Å structure, lack of agreement with extended X‐ray absorption fine structure (EXAFS) data led to the notion that the WOC suffered from X‐ray photoreduction. In the recent 1.95 Å structure, Mn photoreduction is not an issue, but poor agreement with computational models which adopt the ‘high’ oxidation state paradigm, has again resulted in criticism of the structure on the basis of contamination with lower S states of the WOC. Here we use DFT modeling to show that the distinct WOC geometries in the 1.9 and 1.95 Å structures can be straightforwardly accounted for when the Mn oxidation states are consistent with the ‘low’ oxidation state paradigm. Remarkably, our calculations show that the two structures are tautomers, related by a single proton relocation.

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Section: Methodsmentioning

confidence: 99%

Resolving the Differences Between the 1.9 Å and 1.95 Å Crystal Structures of Photosystem II: A Single Proton Relocation Defines Two Tautomeric Forms of the Water‐Oxidizing Complex

2015

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“…Conventionally, α‐bromination of furan rings is achieved by using bromine or N ‐bromosuccinimide as brominating agents. [ 43‐49 ] In this study, we envisaged that using LiBr/K 2 S 2 O 8 instead could be more environmentally benign and industrially accessible (Scheme 3). Methyl furan‐2‐carboxylate has been employed as the model substrate (Table 1).…”

Section: Resultsmentioning

confidence: 99%

Synthesis of [2,2’]Bifuranyl‐5,5’‐dicarboxylic Acid Esters via Reductive Homocoupling of 5‐Bromofuran‐2‐carboxylates Using Alcohols as Reductants^†

Xie

Luo

et al. 2020

Chin. J. Chem.

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Bifuranyl dicarboxylates | Homocoupling | Bromination | Green reductant Herein, we describe an environmentally benign and cost-effective protocol for the synthesis of valuable bifuranyl dicarboxylates, starting with α-bromination of readily accessible furan-2-carboxylates by LiBr and K 2 S 2 O 8. Furthermore, the bromination intermediate product 5-bromofuran-2-carboxylates were then conducted in a palladium-catalyzed reductive homocoupling reactions in the presence of alcohols to afford bifuranyl dicarboxylates. One of the final products in this protocol, *2,2'+bifuran-5,5'-dicarboxylic acid esters, are essential monomers of poly(ethylene bifuranoate), which can be served as an green and versatile alternative polymer for traditional poly(ethylene terephthalate) that is currently common in technical plastics.

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“…o ‐Hydroxyalkynyl substituents can cyclize spontaneously to form furan rings 13h,17 . Recently, we exploited this phenomenon to prepare fused heterocycles of 2‐substituted benzofurans from o ‐iodophenols and terminal alkynes catalyzed by palladium supported on nanosized carbon balls under copper‐ and ligand‐free conditions 16f .…”

Section: Resultsmentioning

confidence: 99%

Copper‐ and Ligand‐free Heteroannulation of o‐Halohydroxypyridine with Terminal Alkynes Using Pd/C Catalyst: One‐Pot Synthesis of 2‐Substituted Furopyridines and their Functionalization

Park

Kim

Yum

et al. 2015

Bulletin Korean Chem Soc

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Three types of isomeric 2-substituted furo [3,2-b]pyridine, furo [2,3-b]pyridine and furo[3,2-c]pyridine were prepared using Pd/C-catalyzed heteroannulation of o-halopyridinols and terminal alkynes under copperand ligand-free conditions. We also demonstrated that double functionalization yielding 2,3-disubstituted furopyridines could be achieved through heteroannulation followed by bromination and Suzuki/Heck reactions. In addition, the use of recoverable Pd/C in the absence of a cocatalyst and ligand can aid in the development of greener chemical processes.

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Furo[3,2-b]pyridine: a convenient unit for the synthesis of polyheterocycles

Cited by 39 publications

References 46 publications

Resolving the Differences Between the 1.9 Å and 1.95 Å Crystal Structures of Photosystem II: A Single Proton Relocation Defines Two Tautomeric Forms of the Water‐Oxidizing Complex

Resolving the Differences Between the 1.9 Å and 1.95 Å Crystal Structures of Photosystem II: A Single Proton Relocation Defines Two Tautomeric Forms of the Water‐Oxidizing Complex

Synthesis of [2,2’]Bifuranyl‐5,5’‐dicarboxylic Acid Esters via Reductive Homocoupling of 5‐Bromofuran‐2‐carboxylates Using Alcohols as Reductants^†

Copper‐ and Ligand‐free Heteroannulation of o‐Halohydroxypyridine with Terminal Alkynes Using Pd/C Catalyst: One‐Pot Synthesis of 2‐Substituted Furopyridines and their Functionalization

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Furo[3,2-b]pyridine: a convenient unit for the synthesis of polyheterocycles

Cited by 39 publications

References 46 publications

Resolving the Differences Between the 1.9 Å and 1.95 Å Crystal Structures of Photosystem II: A Single Proton Relocation Defines Two Tautomeric Forms of the Water‐Oxidizing Complex

Resolving the Differences Between the 1.9 Å and 1.95 Å Crystal Structures of Photosystem II: A Single Proton Relocation Defines Two Tautomeric Forms of the Water‐Oxidizing Complex

Synthesis of [2,2’]Bifuranyl‐5,5’‐dicarboxylic Acid Esters via Reductive Homocoupling of 5‐Bromofuran‐2‐carboxylates Using Alcohols as Reductants†

Copper‐ and Ligand‐free Heteroannulation of o‐Halohydroxypyridine with Terminal Alkynes Using Pd/C Catalyst: One‐Pot Synthesis of 2‐Substituted Furopyridines and their Functionalization

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Synthesis of [2,2’]Bifuranyl‐5,5’‐dicarboxylic Acid Esters via Reductive Homocoupling of 5‐Bromofuran‐2‐carboxylates Using Alcohols as Reductants^†