Regioselective Transition‐Metal‐Free C(sp²)−H Borylation: A Subject of Practical and Ongoing Interest in Synthetic Organic Chemistry

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(44)

Published: Aug. 10, 2022

Abstract Considerable advances have been made in the area of C−H functionalization last few decades. A number approaches including both directed and nondirected strategies developed thus far. Among various functionalizations, borylation is special interest due to wide applications organoboron compounds. In this regard, transition‐metal‐catalyzed regioselective developed. However, major concern regarding metal‐catalyzed procedures requirement a precious metal as well contamination by precursors desired products, which limit application process large‐scale synthesis. Therefore, recent trends involved use transition‐metal‐free systems. We summarize developments borylation. believe that Review will help increase field stimulate further progress.

Language: Английский

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Metal‐Free Phosphorus‐Directed Borylation of C(sp²)−H Bonds

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 61(1)

Published: Nov. 1, 2021

Spectacular progress has recently been achieved in transition metal-catalyzed C-H borylation of phosphines as well directed electrophilic borylation. As shown here, P-directed provides a new, straightforward, and efficient access to phosphine-boranes. It operates under metal-free conditions leverages simple, readily available substrates. is applicable broad range backbones (naphthyl, biphenyl, N-phenylpyrrole, binaphthyl, benzyl, naphthylmethyl) gives facile various substitution patterns at boron (by varying the electrophile or post-derivatizing borane moiety). NMR monitoring supports involvement P-stabilized borenium cations key intermediates. DFT calculations reveal existence stabilizing effect π-arene/boron interactions (biphenyl)(i-Pr)2 P→BBr2+ species.

Language: Английский

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Adamantane-1-Carbonyl-Directed C–H Borylation and Hydroxylation of Benzenethiols

Organic Letters, Journal Year: 2022, Volume and Issue: 24(39), P. 7163 - 7167

Published: Sept. 27, 2022

A novel route has been described for C–H borylation and hydroxylation of benzenethiols directed by adamantane-1-carbonyl using BBr3. The protocol generates corresponding arylboronic esters phenols in moderate to excellent yields under metal-free conditions. In addition, the borylated product can be transformed directing group removed good yields, which will facilitate synthesis structurally diverse benzenethiols.

Language: Английский

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Metal-Free Boron-Mediated ortho-C–H Hydroxylation of N-Benzyl-3,4,5-tribromopyrazoles

Organic Letters, Journal Year: 2022, Volume and Issue: 24(19), P. 3570 - 3575

Published: May 5, 2022

A novel route has been reported for C-H hydroxylation of benzyl compounds directed by a 3,4,5-tribromopyrazole auxiliary via boronation/oxidation using BBr3 and NaBO3·4H2O. The strategy exhibits outstanding site selectivity affords the corresponding phenols in moderate to excellent yields under metal-free conditions. Besides, this protocol can be achieved one pot, which is highly promising as practical method use multistep organic synthetic process.

Language: Английский

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C–H Borylation of Benzophenones Using Hydrazone as the Traceless Directing Group

Organic Letters, Journal Year: 2023, Volume and Issue: 25(31), P. 5875 - 5879

Published: July 27, 2023

C–H borylation is one of the powerful bond functionalization reactions. In this context, a metal-free benzophenones using hydrazone as traceless directing group has been reported. The dibromoboron intermediates can be obtained in excellent yields, and corresponding arylboronic esters are generated moderate to yields. Furthermore, borylated compounds transformed one-pot method, avoiding loss overall yield caused by separation esters.

Language: Английский

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Metal-Free ortho C–H Borylation of Thiobenzamides

Organic Letters, Journal Year: 2024, Volume and Issue: 26(18), P. 3709 - 3714

Published: May 1, 2024

A BBr3-mediated S-directed ortho C–H borylation of thiobenzamides was developed. variety ortho-borylated were obtained in moderate to good yields with a wide functional group tolerance under simple and metal-free conditions. This transformation provided convenient practical route important functionalized thiobenzamides.

Language: Английский

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Chemoselective C–H Hydroxylation and Borylation of N-Phenylbenzamides using BBr₃

Organic Letters, Journal Year: 2024, Volume and Issue: 26(22), P. 4631 - 4636

Published: May 23, 2024

A novel metal-free chemoselective C–H hydroxylation and borylation of N-phenylbenzamides using BBr3 is described. The protocol generates the corresponding phenols arylboronic esters in moderate to excellent yields under mild conditions with brilliant chemoselectivity. Additionally, this strategy can be realized one pot, several potential bioactive derivatives synthesized efficiently. Density functional theory calculations certify that preferred pathway for process formation a five-membered boracycle.

Language: Английский

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Copper‐Catalyzed Preparation of Alkenylboronates and Arylboronates

European Journal of Organic Chemistry, Journal Year: 2021, Volume and Issue: 2021(45), P. 6115 - 6160

Published: Oct. 22, 2021

Abstract Organoboron compounds, especially alkenylboronates and arylboronates are highly useful reagents versatile building blocks in the modern synthetic chemistry toolbox. This review focuses on copper‐catalyzed routes to access alkenyl‐ arylboronate esters. Various copper salts ligands have been employed them excellent regio‐ stereoselectivity as well high yields. Both addition substitution reactions highlighted based various methodologies including hydroboration, carboboration, borylative opening of propargyl three‐ four‐membered rings, dehalogenative borylation alkenyl bromides iodides, defluoroborylation fluoroalkenes direct C(sp 2 )−H bond activation alkenes. Preparation involving aryl halides, arenes cascade 1,3‐halogen migration/borylation 2‐halostyrenes reviewed. Mechanistic aspects those discussed briefly.

Language: Английский

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Boron‐Mediated Regioselective Aromatic C−H Functionalization via an Aryl BF₂Complex

Chemistry - A European Journal, Journal Year: 2022, Volume and Issue: 29(10)

Published: Nov. 16, 2022

An efficient regioselective functionalization of 2-aryl-heteroarenes and aryl aldehydes via an azaaryl BF2 complex has been developed. Mechanistically the reaction comprises fluoride to bromide ligand exchange on boron species consecutive C-B bond cleavage deliver a broad range functionalized products. The is high yielding, substrate scope where several different heteroarenes can be with chloro, bromo, iodo, hydroxyl, amine in highly fashion. method applied for late-stage or rapid skeleton remodeling instance cross-couplings.

Language: Английский

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Transition Metal‐Free Aromatic C−H, C−N, C−S and C−O Borylation

The Chemical Record, Journal Year: 2023, Volume and Issue: 23(4)

Published: Feb. 27, 2023

Abstract Aromatic organoboron compounds are highly valuable building blocks in organic chemistry. They were mainly synthesized through aromatic C−H and C−Het borylation, which transition metal‐catalysis dominate. In the past decade, with increasing attention to sustainable chemistry, numerous metal‐free borylation transformations have been developed emerged as efficient methods towards synthesis of compounds. This account focuses on recent advances C−H, C−N, C−S, C−O provides insights where further developments required.

Language: Английский

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