Directed C–H borylation: From metal catalysis to metal free DOI

Jiahang Lü,

Zhuangzhi Shi

Chinese Science Bulletin (Chinese Version), Journal Year: 2022, Volume and Issue: 67(32), P. 3824 - 3835

Published: July 19, 2022

Organoborons play a highly important role in many science fields, range from synthetic chemistry to materials medicinal chemistry. The C−H borylation strategy has made significant development recent decades, and its reaction system is changing noble-metal catalysis more environmentally friendly metal-free systems. Typically, an organic molecule contains multiple bonds with subtle difference activation barrier. Therefore, controlling the positional selectivity represents key challenge complex molecules. To override this intrinsic selectivity, introducing directing group molecules can exhibit different site-selectivity. This review focuses on of ortho-selective (hetero)arenes by various groups, including: (1) Metal-catalyzed directed borylation; (2) borylation. shifting noble metals systems, breaking through dependence traditional means metal catalysts broadening concept C–H functionalization. In first section, transition for C−H borylation summarized. Among catalysts, iridium complexes have proven be most active toward 16e intermediate [Ir(dtbpy)(Bpin)3] (dtbpy=4,4′-di-tert-butyl-2,2′-bipyridine, Bpin = 4,4,5,5-tetramethyl-1,3,2-dioxaborolane) been proved catalytically species [Ir(X)(cod)]2/dtbpy (X=OMe or Cl, cod=1,5-cyclooctadiene) catalyzed Three strategies developed direct regioselective bond borylation: Chelate directed, relay outer-sphere directed. Notably, dimethylsilyl employed as Ir-catalyzed ortho-borylation arenes. addition iridium, use other including rhodium palladium met some success well. second section analyses disadvantages catalysts. requirement precious residues final product will limit application these processes, especially large-scale synthesis. Alternatively, novel electrophilic borylations arenes reported which proceed via borenium boronium species, but stoichiometric quantities by-products are formed at same time. simpler efficient desirable. Then we show our discovery talent approach indoles, pyrroles amides using readily available BBr3 without any additive. Other groups also similar examples after discovery. concluding discusses significance under conditions, limitations known approaches field. additional breakthroughs required further advance functionalization described review. We hope that not only present exciting new discoveries feedstock chemicals into valuable organoboron products, provide guidance researchers, drug natural research, facilitating continued

Language: Английский

Accelerated photochemical reactions at oil-water interface exploiting melting point depression DOI
Ya‐Ming Tian, Wagner Silva, Ruth M. Gschwind

et al.

Science, Journal Year: 2024, Volume and Issue: 383(6684), P. 750 - 756

Published: Feb. 15, 2024

Water can accelerate a variety of organic reactions far beyond the rates observed in classical solvents. However, using pure water as solvent introduces solubility constraints that have limited applicability efficient photochemistry particular. We report here formation aggregates between pairs arenes, heteroarenes, enamines, or esters with different electron affinities an aqueous medium, leading to oil-water phase boundary through substrate melting point depression. The active hydrogen atoms reactants engage bonds water, thereby accelerating photochemical reactions. This methodology realizes appealingly simple conditions for coupling complex solid molecules, including drug molecules are poorly soluble water.

Language: Английский

Citations

35
Regioselective Transition‐Metal‐Free C(sp2)−H Borylation: A Subject of Practical and Ongoing Interest in Synthetic Organic Chemistry DOI Open Access
Supriya Rej, Naoto Chatani

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

Citations

59
Metal-Free ortho C–H Borylation of Thiobenzamides DOI

Jianxing Lv,

Yixuan Liang,

Y. OUYANG

et al.

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

Citations

4
Chemoselective C–H Hydroxylation and Borylation of N-Phenylbenzamides using BBr3 DOI
Weiming Chen,

Jiatao Xia,

Jiuzhong Huang

et al.

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

Citations

4
Site-selective electrochemical C–H silylations of pyridines enabled by temporary reductive dearomatization DOI
Zhihao Yang, Xuan Liu, Tianyuan Zhang

et al.

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(19), P. 5545 - 5552

Published: Jan. 1, 2024

Site-selective silylations of electron-deficient pyridines is presented, the C4-to-C5 selectivity can be controlled by adjusting bulkiness chlorosilanes.

Language: Английский

Citations

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

Zhaoziyuan Yang,

Xiaobo Xu

et al.

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

Citations

19
C–H Borylation of Benzophenones Using Hydrazone as the Traceless Directing Group DOI

Zhaoziyuan Yang,

Liqiang Hao,

Xiaobo Xu

et al.

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

Citations

11
Redox-Neutral Cyclization of 2-Isocyanobiaryls through Photoredox/PPh3 Dual Catalysis DOI
Xiaoting Wu, Pu Chen,

Mengran Gan

et al.

Organic Letters, Journal Year: 2023, Volume and Issue: 25(51), P. 9186 - 9190

Published: Dec. 15, 2023

The photoredox/PPh3-mediated cyclization of 2-isocyanobiaryls has been developed. A substantial range functional-group-rich phenanthridine derivatives were synthesized at room temperature in a highly selective and atom-economic manner. Mechanistic studies suggested that the process is probably mediated both by Ph3P radical cation with key 1,2-hydride transfer hydrogen atom generated through O–H bond homolytic cleavage Ph3P–OH intermediate.

Language: Английский

Citations

11
Transition Metal‐Free Aromatic C−H, C−N, C−S and C−O Borylation DOI

Lu Luo,

Shuai Tang, Jiangyue Wu

et al.

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

Citations

10
BBr3-Mediated ortho C–H Borylation of Benzamides DOI
Yixuan Liang,

Chengyu Du,

C. Dong

et al.

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: April 25, 2025

We have developed a BBr3-mediated, metal-free ortho C-H borylation of benzamides, enabling the synthesis wide range ortho-borylated benzamides in moderate to good yields. This transformation offers convenient strategy for accessing functionalized which are valuable intermediates pharmaceuticals, agrochemicals, and fine chemical synthesis.

Language: Английский

Citations

0