scholarly journals A General Approach to Deboronative Radical Chain Reaction with Pinacol Alkylboronic Esters

2020 ◽  
Author(s):  
Emy André-Joyaux ◽  
Andrey Kuzovlev ◽  
Nicholas D. C. Tappin ◽  
Philippe Renaud
Keyword(s):  
Coupling Reaction ◽  
Lewis Acidity ◽  
One Pot ◽  
Radical Chain ◽  
Boronic Esters ◽  
Boron Chemistry ◽  
Substoichiometric Amount ◽  
Radical Traps ◽  
Radical Chain Reaction

The generation of carbon-centered radicals from air-sensitive organoboron compounds via nucleohomolytic substitution at boron is one of the most general methods to generate non-functionalized and functionalized radicals. Due to their reduced Lewis acidity, the very popular, air-stable, and readily available alkylboronic pinacol esters are not suitable substrates for this process. Herein, is reported their <i>in situ</i> conversion to alkylboronic catechol esters by boron-transesterification with a substoichiometric amount of catechol methyl borate (MeO–Bcat) telescoped onto a wide array of radical chain processes. This simple one-pot, radical-chain, deboronative protocol allows for the conversion of pinacol boronic esters into iodides, bromides, chlorides, and thioethers. The process is also suitable the formation of nitriles and allylated compounds via C–C bond formation using sulfonyl radical traps. Finally, a particularly mild protocol for the protodeboronation of pinacol boronic esters is given. The power of combining radical and classical boron chemistry, is illustrated with a highly modular 5-membered ring formation using a combination of a three-component coupling reaction and a protodeboronative cyclization.

scholarly journals A General Approach to Deboronative Radical Chain Reaction with Pinacol Alkylboronic Esters

2020 ◽  
Author(s):  
Emy André-Joyaux ◽  
Andrey Kuzovlev ◽  
Nicholas D. C. Tappin ◽  
Philippe Renaud
Keyword(s):  
Coupling Reaction ◽  
Lewis Acidity ◽  
One Pot ◽  
Radical Chain ◽  
Boronic Esters ◽  
Boron Chemistry ◽  
Substoichiometric Amount ◽  
Radical Traps ◽  
Radical Chain Reaction

The generation of carbon-centered radicals from air-sensitive organoboron compounds via nucleohomolytic substitution at boron is one of the most general methods to generate non-functionalized and functionalized radicals. Due to their reduced Lewis acidity, the very popular, air-stable, and readily available alkylboronic pinacol esters are not suitable substrates for this process. Herein, is reported their <i>in situ</i> conversion to alkylboronic catechol esters by boron-transesterification with a substoichiometric amount of catechol methyl borate (MeO–Bcat) telescoped onto a wide array of radical chain processes. This simple one-pot, radical-chain, deboronative protocol allows for the conversion of pinacol boronic esters into iodides, bromides, chlorides, and thioethers. The process is also suitable the formation of nitriles and allylated compounds via C–C bond formation using sulfonyl radical traps. Finally, a particularly mild protocol for the protodeboronation of pinacol boronic esters is given. The power of combining radical and classical boron chemistry, is illustrated with a highly modular 5-membered ring formation using a combination of a three-component coupling reaction and a protodeboronative cyclization.

A facile and convenient sequential homobimetallic catalytic approach towards β-methylstyrenes. A one-pot Stille cross-coupling/isomerization strategy

2014 ◽  
Vol 12 (22) ◽  
pp. 3735-3743 ◽  
Author(s):  
Sebastián O. Simonetti ◽  
Enrique L. Larghi ◽  
Teodoro S. Kaufman
Keyword(s):  
Double Bond ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Aryl Halides ◽  
One Pot ◽  
Cross Coupling Reaction

A one-pot approach towards β-methylstyrenes is reported. The transformation involves a Stille cross-coupling reaction of aryl halides with allyltributylstannane, followed by an in situ Pd-catalyzed double bond conjugative migration.

scholarly journals A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones

2021 ◽  
Vol 17 ◽  
pp. 2906-2914
Author(s):  
Yuki Yamamoto ◽  
Akihiro Tabuchi ◽  
Kazumi Hosono ◽  
Takanori Ochi ◽  
Kento Yamazaki ◽  
...  
Keyword(s):  
Large Scale ◽  
Phase System ◽  
Methyl Ethyl ◽  
Two Phase ◽  
One Pot ◽  
Mild Conditions ◽  
Substoichiometric Amount ◽  
Practical Synthesis ◽  
Industrial Use

A simple and efficient method for α-brominating lactones that affords α-bromolactones under mild conditions using tetraalkylammonium hydroxide (R4N+OH−) as a base was developed. Lactones are ring-opened with Br2 and a substoichiometric amount of PBr3, leading to good yields of the corresponding α-bromocarboxylic acids. Subsequent intramolecular cyclization over 1 h using a two-phase system (H2O/CHCl3) containing R4N+OH− afforded α-bromo lactones in good yields. This method can be applied at the 10 mmol scale using simple operations. α-Bromo-δ-valerolactone, which is extremely reactive and difficult to isolate, could be isolated and stored in a freezer for about one week using the developed method. Optimizing the solvent for environmentally friendly large-scale syntheses revealed that methyl ethyl ketone (MEK) was as effective. In addition, in situ-generated α-bromo-δ-valerolactone was directly converted into a sulfur-substituted functional lactone without difficulty by reacting it with a sulfur nucleophile in one pot without isolation. This new bromination system is expected to facilitate the industrial use of α-bromolactones as important intermediates.

Copper-Mediated One-Pot Synthesis of Indoles through Sequential Hydroamination and Cross-Dehydrogenative Coupling Reaction

Synthesis ◽  
2019 ◽  
Vol 52 (01) ◽  
pp. 75-84 ◽  
Author(s):  
Peng Sun ◽  
Jiaojiao Yang ◽  
Zirui Song ◽  
Yichao Cai ◽  
Yajie Liu ◽  
...  
Keyword(s):  
Mixed Solvents ◽  
Coupling Reaction ◽  
One Pot ◽  
One Pot Synthesis ◽  
Dehydrogenative Coupling ◽  
High Yields

Starting from simple anilines and ester arylpropiolates, an efficient one-pot synthesis of 2-arylindole-3-carboxylate derivatives has been developed through copper-mediated sequential hydroamination and cross-dehydrogenative coupling (CDC) reaction. The initial hydroamination of anilines to ester arylpropiolates in benzene can proceed in a stereoselective manner to give ester (Z)-3-(arylamino)acrylates in the presence of CuCl2/phenanthroline, KMnO4, and KHCO3 at 120 °C. Sequentially, these in situ functionalized adducts can undergo direct intramolecular oxidative alkenylation of aromatic C–H bond in mixed solvents (benzene/DMSO 1:1) at 130 °C affording multi-substituted­ indoles in good to high yields.

scholarly journals A one-pot in-situ synthesis of copper cluster doped hydrogen substituted graphdiyne nanofibers (Cu-HsGDY)

2021 ◽  
Vol 261 ◽  
pp. 02055
Author(s):  
Wenjun Hao ◽  
Lei Jin ◽  
Rong Fan ◽  
Xinyu Su ◽  
Zongping Chen
Keyword(s):  
Flexible Electronics ◽  
Coupling Reaction ◽  
Similar Process ◽  
Stable Configuration ◽  
Synthetic Approach ◽  
Copper Cluster ◽  
One Pot ◽  
Cross Coupling Reaction ◽  
New Type

Graphdiyne (GDY) is a new type of two-dimensional (2D) carbon materials, in which two benzene rings are chained by diacetylenic linkages (-C≡C-C≡C-). γ-GDY is the most studied GDY due to its stable configuration and was experimentally obtained in 2010 through cross coupling reaction by using hexaethynylbenzene as precursor. Hydrogen substituted graphdiyne (HsGDY) was obtained using 1, 3, 5-triethynylbenzene as precursor in a similar process. Hereinto, a copper cluster doped hydrogen substituted graphdiyne nanofibers (Cu-HsGDY) were prepared through a facile one-pot in-situ synthetic approach in a good reproductive manner. Through simply removing the copper foil, the obtained robust Cu-HsGDY can be transferred onto arbitrary substrates, especially flexible substrates, such as polyethylene terephthalate (PET), which can be used as flexible electronics as future materials.

scholarly journals Iron-Catalyzed Cross-Coupling of Bis-(aryl)manganese Nucleophiles with Alkenyl Halides: Optimization and Mechanistic Investigations

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 723 ◽  
Author(s):  
Lidie Rousseau ◽  
Alexandre Desaintjean ◽  
Paul Knochel ◽  
Guillaume Lefèvre
Keyword(s):  
Reaction Mechanism ◽  
1H Nmr ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
One Pot ◽  
Aryl Bromides ◽  
Cross Coupling Reaction ◽  
Manganese Species

Various substituted bis-(aryl)manganese species were prepared from aryl bromides by one-pot insertion of magnesium turnings in the presence of LiCl and in situ trans-metalation with MnCl2 in THF at −5 °C within 2 h. These bis-(aryl)manganese reagents undergo smooth iron-catalyzed cross-couplings using 10 mol% Fe(acac)3 with various functionalized alkenyl iodides and bromides in 1 h at 25 °C. The aryl-alkenyl cross-coupling reaction mechanism was thoroughly investigated through paramagnetic 1H-NMR, which identified the key role of tris-coordinated ate-iron(II) species in the catalytic process.

Synthesis of Internal Alkynes through an Effective Tandem ­Elimination–Hydrodebromination–Cross-Coupling of gem-­Dibromoalkenes with Halobenzenes

Synlett ◽  
2017 ◽  
Vol 29 (02) ◽  
pp. 209-214 ◽  
Author(s):  
Yuan Ji ◽  
Ning Zhong ◽  
Zinan Kang ◽  
Guobing Yan ◽  
Ming Zhao
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Sonogashira Coupling ◽  
Reaction Conditions ◽  
One Pot ◽  
Cross Coupling Reaction ◽  
Sonogashira Coupling Reaction ◽  
Palladium Catalyzed ◽  
Internal Alkyne

Carbon–carbon couplings are among the most important strategies for constructing functional molecules in organic synthetic chemistry, and cheap, diverse, and readily available coupling partners are crucial to these diverse reactions. In this contribution, we report the first palladium-catalyzed C–C cross-coupling reaction of two kinds of organic halide, a gem-dibromoalkene and a halobenzene, as the starting materials. Terminal alkynes were generated in situ through a tandem elimination–hydrodebromination process, and the internal alkyne final products were synthesized in one pot. The reaction proceeded under simple, facile, and classic copper-free Sonogashira coupling reaction conditions in good to excellent yields.

An Iron-Based Catalyst Enables The Enantioconvergent Synthesis of Chiral 1,1-Diarylalkanes Through a Suzuki-Miyaura Cross-Coupling Reaction

2020 ◽  
Author(s):  
Chet Tyrol ◽  
Nang Yone ◽  
Connor Gallin ◽  
Jeffery Byers
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Radical Intermediates ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Boronic Esters ◽  
Carbon Centered Radical ◽  
Iron Based ◽  
High Yields

By using an iron-based catalyst, access to enantioenriched 1,1-diarylakanes was enabled through an enantioselective Suzuki-Miyaura crosscoupling reaction. The combination of a chiral cyanobis(oxazoline) ligand framework and 1,3,5-trimethoxybenzene additive were essential to afford high yields and enantioselectivities in cross-coupling reactions between unactivated aryl boronic esters and a variety of benzylic chlorides, including challenging ortho-substituted benzylic chloride substrates. Mechanistic investigations implicate a stereoconvergent pathway involving carbon-centered radical intermediates.

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