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Chen F, Zhao XX, Zhang HT, Ma YN, Chen X. Facile Friedel-Crafts alkylation of arenes under solvent-free conditions. Org Biomol Chem 2024; 22:2187-2191. [PMID: 38391292 DOI: 10.1039/d4ob00162a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
The Friedel-Crafts alkylation of arenes is an important part of electrophilic aromatic substitution reactions. However, the reactivity of arenes is weakened by electron-withdrawing substituents, leading to limited substrate scopes and applications. Herein, we developed an efficient HOTf-promoted Friedel-Crafts alkylation reaction of broad arenes with α-aryl-α-diazoesters under metal-free and solvent-free conditions.
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Affiliation(s)
- Feijing Chen
- College of Chemistry, Zhengzhou University, Zhengzhou, 450001, Henan, China.
| | - Xiao-Xiao Zhao
- College of Chemistry, Zhengzhou University, Zhengzhou, 450001, Henan, China.
| | - Hao-Tian Zhang
- College of Chemistry, Zhengzhou University, Zhengzhou, 450001, Henan, China.
| | - Yan-Na Ma
- College of Chemistry, Zhengzhou University, Zhengzhou, 450001, Henan, China.
| | - Xuenian Chen
- College of Chemistry, Zhengzhou University, Zhengzhou, 450001, Henan, China.
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Chen F, Guo W, Ma YN, Chen X. 9,9'-Bis- o-carboranes: synthesis and exploration of properties. Chem Commun (Camb) 2024; 60:614-617. [PMID: 38100063 DOI: 10.1039/d3cc05041f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
A highly efficient Pd-catalyzed B(9)-H/B(9)-H oxidative dehydrogenation coupling of carboranes to synthesize 9,9'-bis-o-carboranes has been developed. The properties and derivatization of 9,9'-bis-o-carborane were also examined, which provided diverse bis-o-carborane derivatives and bis-nido-carborane.
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Affiliation(s)
- Feijing Chen
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China.
| | - Wenjing Guo
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China.
| | - Yan-Na Ma
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China.
| | - Xuenian Chen
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China.
- School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, Henan Normal University, Xinxiang, Henan 453007, China
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Wu Y, Lu W, Ma YN, Chen F, Ren W, Chen X. Trifluoromethanesulfonic Acid Promoted Controllable Electrophilic Aromatic Nitration. J Org Chem 2023. [PMID: 37463455 DOI: 10.1021/acs.joc.3c00892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
In this work, we developed a facile and controllable electrophilic aromatic nitration method with commercially available 68% HNO3 as the nitrating reagent and trifluoromethanesulfonic acid (HOTf) as the catalyst in hexafluoroisopropanol or under solvent-free conditions. The electrophilic nitration products of different arenes can be obtained in almost quantitative yields by tuning the loading of HOTf. The strong acidity and water absorbing property of HOTf allowed this transformation to reach completion in a short time at room temperature.
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Affiliation(s)
- Yanxuan Wu
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Wen Lu
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Yan-Na Ma
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Feijing Chen
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Wei Ren
- Henan Scientific Research Platform Service Center, Zhengzhou 450000, China
| | - Xuenian Chen
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
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Ma YN, Ren H, Wu Y, Li N, Chen F, Chen X. B(9)-OH- o-Carboranes: Synthesis, Mechanism, and Property Exploration. J Am Chem Soc 2023; 145:7331-7342. [PMID: 36962083 DOI: 10.1021/jacs.2c13570] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2023]
Abstract
Herein, we present a chemically robust and efficient synthesis route for B(9)-OH-o-carboranes by the oxidation of o-carboranes with commercially available 68% HNO3 under the assistance of trifluoromethanesulfonic acid (HOTf) and hexafluoroisopropanol (HFIP). The reaction is highly efficient with a wide scope of carboranes, and the selectivity of B(9)/B(8) is up to 98:2. The success of this transformation relies on the strong electrophilicity and oxidizability of HNO3, promoted through hydrogen bonds of the Brønsted acid HOTf and the solvent HFIP. Mechanism studies reveal that the oxidation of o-carborane involves an initial electrophilic attack of HNO3 to the hydrogen atom at the most electronegative B(9) of o-carborane. In this transformation, the hydrogen atom of the B-H bond is the nucleophilic site, which is different from the electrophilic substitution reaction, where the boron atom is the nucleophilic site. Therefore, this is an oxidation-reduction reaction of o-carborane under mild conditions in which N(V) → N(III) and H(-I) → H(I). The derivatization of 9-OH-o-carborane was further examined, and the carboranyl group was successfully introduced to an amino acid, polyethylene glycol, biotin, deoxyuridine, and saccharide. Undoubtedly, this approach provides a selective way for the rapid incorporation of carborane moieties into small molecules for application in boron neutron capture therapy, which requires the targeted delivery of boron-rich groups.
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Affiliation(s)
- Yan-Na Ma
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Huazhan Ren
- School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, Henan Normal University, Xinxiang, Henan 453007, China
| | - Yanxuan Wu
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Na Li
- School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, Henan Normal University, Xinxiang, Henan 453007, China
| | - Feijing Chen
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Xuenian Chen
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
- School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, Henan Normal University, Xinxiang, Henan 453007, China
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Lu W, Wu Y, Ma YN, Chen F, Chen X. A Method for Highly Selective Halogenation of o-Carboranes and m-Carboranes. Inorg Chem 2023; 62:885-892. [PMID: 36584667 DOI: 10.1021/acs.inorgchem.2c03694] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A facile halogenation method for highly selective synthesis of 9-X-o-carboranes, 9,12-X2-o-carboranes, 9-X-12-X'-o-carboranes, 9-X-m-carboranes, 9,10-X2-m-carboranes, and 9-X-10-X'-m-carboranes (X, X' = Cl, Br, I) has been developed on the basis of our previous work. The success of this transformation relies on the usage of trifluoromethanesulfonic acid (HOTf), the easily available strong Brønsted acid. The addition of HOTf greatly increases the electrophilicity of N-haloamides through hydrogen bonding interaction, resulting in the low loading of N-haloamides, short reaction time, and mild reaction conditions. Additionally, the solvent 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) is also essential to further increase the acidity of HOTf.
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Affiliation(s)
- Wen Lu
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Yanxuan Wu
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Yan-Na Ma
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Feijing Chen
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Xuenian Chen
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
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