Urea‐Promoted Metal‐Free Homolytic Alkynyl Substitution (HAS): Metal‐Free C−C Coupling of Alkynyl Bromides Formed In Situ from 1,1‐Dibromoalkenes

Morri, Ashok K.; Thummala, Yadagiri; Ghosh, Subhash; Doddi, Venkata Ramana

doi:10.1002/slct.202100243

Cited by 3 publications

(4 citation statements)

References 56 publications

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“…13 C NMR (100 MHz, CDCl 3 ) δ 139.63, 132.53, 129.35, 118.95, 81.69, 73.60, 21.76. 1,4-bis(4-isopropylphenyl)buta-1,3-diyne (2c) [5]. White solid.…”

Section: Characterization Data Of the Productsmentioning

confidence: 99%

“…55, 128.69, 119.14, 81.73, 73.64, 36.11, 31.58, 30.99, 22.65, 14.14. 1,4-di([1,1 -biphenyl]-4-yl)buta-1,3-diyne (2i) [5]. White solid.…”

Section: Characterization Data Of the Productsmentioning

confidence: 99%

“…Alkynes are important structural units existing in a wide range of natural products, pharmaceuticals, and material functional molecules [ 1 , 2 , 3 ]. Alkynes also as building blocks play generally an important role in organic synthesis due to the diverse reactivity [ 4 , 5 , 6 , 7 ]. Particularly, conjugate 1,3-dialkynes are valuable building blocks for the synthesis of linearly π-conjugated acetylenic oligomers and polymers [ 8 , 9 ], supramolecular materials [ 10 , 11 ], and substituted heterocyclic compounds [ 12 , 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

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A Simple and Practical Bis-N-Heterocyclic Carbene as an Efficient Ligand in Cu-Catalyzed Glaser Reaction

et al. 2023

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Conjugated diyne derivatives are important scaffolds in modern organic synthetic chemistry. Using the Glaser reaction involves the coupling of terminal alkynes which can efficiently produce conjugated diyne derivatives, while the use of a stoichiometric amount of copper salts, strong inorganic base, and excess oxidants is generally needed. Developing an environmentally friendly and effective method for the construction of symmetrical 1,3-diynes compounds by Glaser coupling is still highly desirable. In this study, we present an economical method for the production of symmetric diynes starting from various terminal acetylenes in a Glaser reaction. A simple and practical bis-N-heterocyclic carbene ligand has been introduced as efficient ligands for the Cu-catalyzed Glaser reaction. High product yields were obtained at 100 °C for a variety of substrates including aliphatic and aromatic terminal alkynes and differently substituted terminal alkynes including the highly sterically hindered substrate 2-methoxy ethynylbenzene or 2-trifluoromethyl ethynylbenzene and a series of functional groups, such as trifluoromethyl group, ester group, carboxyl group, and nitrile group. The established protocol is carried out in air under base-free condition and is operationally simple. These research work suggest that bis-N-heterocyclic carbene could also an appealing ligand for Glaser reaction and provide a reference for the preparation of symmetric 1,3-diynes in industrial filed.

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“…13 C NMR (100 MHz, CDCl 3 ) δ 139.63, 132.53, 129.35, 118.95, 81.69, 73.60, 21.76. 1,4-bis(4-isopropylphenyl)buta-1,3-diyne (2c) [5]. White solid.…”

Section: Characterization Data Of the Productsmentioning

confidence: 99%

“…55, 128.69, 119.14, 81.73, 73.64, 36.11, 31.58, 30.99, 22.65, 14.14. 1,4-di([1,1 -biphenyl]-4-yl)buta-1,3-diyne (2i) [5]. White solid.…”

Section: Characterization Data Of the Productsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Simple and Practical Bis-N-Heterocyclic Carbene as an Efficient Ligand in Cu-Catalyzed Glaser Reaction

et al. 2023

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“…The origin of the other common byproduct, namely, the reductively homo-coupled 1-haloalkyne, is less well understood but potentially involves a complementary Cu(0) → Cu(II) mediated process. Preparative syntheses of symmetric buta-1,3-diynes from 1-haloalkynes have been reported using various methods including [Pd(PPh 3 ) 4 ] or Cu powder. − …”

mentioning

confidence: 99%

Air Tolerant Cadiot–Chodkiewicz and Sonogashira Cross-Couplings

Fung,

Sowden,

Coote

et al. 2023

Org. Lett.

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Cadiot−Chodkiewicz cross-couplings generate an unsymmetric buta-1,3-diyne by way of a Cu(I)-catalyzed coupling between a terminal alkyne and a 1-haloalkyne. Despite their widespread use, Cadiot−Chodkiewicz reactions are plagued by the generation of symmetric buta-1,3-diyne side products, formed through competing: (a) formal reductive homo-coupling of the 1haloalkyne and (b) oxidative (Glaser−Hay/Eglinton) homo-coupling of the terminal alkyne. To overcome this issue, a large excess of one of the two reacting alkynes is commonly deployed, and difficult separations of cross-and homo-coupled products are often encountered. Here, we demonstrate that the use of ascorbate as a reductant leads to a suppression of these unwanted side reactions, hence permitting excellent yields with a roughly stoichiometric ratio of reactants. The procedure also avoids an inert gas atmosphere and uses a sustainable solvent. A similar approach is effective for cross-couplings involving a Pd(0)/Pd(II) catalytic cycle, with air tolerant Sonogashira couplings also established.

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Iron-Catalyzed Cadiot–Chodkiewicz Coupling with High Selectivity in Water under Air

et al. 2022

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An iron-based catalytic system was developed for the cross-coupling of 1-bromoalkynes with terminal alkynes to selectively generate unsymmetrical 1,3-butadiynes in water under air. It was found that a combination of 1-bromoalkynes derived from less acidic terminal alkynes with more acidic counterparts would greatly enhance yields and selectivity for unsymmetrical 1,3butadiynes. The reaction was also applicable for the synthesis of unsymmetrical 1,3,5-hexatriynes through coupling of 1-bromoalkynes and trimethylsilyl-protected 1,3-butadiynes in a one-pot manner.

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Urea‐Promoted Metal‐Free Homolytic Alkynyl Substitution (HAS): Metal‐Free C−C Coupling of Alkynyl Bromides Formed In Situ from 1,1‐Dibromoalkenes

Cited by 3 publications

References 56 publications

A Simple and Practical Bis-N-Heterocyclic Carbene as an Efficient Ligand in Cu-Catalyzed Glaser Reaction

A Simple and Practical Bis-N-Heterocyclic Carbene as an Efficient Ligand in Cu-Catalyzed Glaser Reaction

Air Tolerant Cadiot–Chodkiewicz and Sonogashira Cross-Couplings

Iron-Catalyzed Cadiot–Chodkiewicz Coupling with High Selectivity in Water under Air

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