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Zhang SY, Tang SB, Jiang YX, Zhu RY, Wang ZX, Long B, Su J. Mechanism of the Visible-Light-Promoted C(sp 3)-H Oxidation via Uranyl Photocatalysis. Inorg Chem 2024; 63:2418-2430. [PMID: 38264973 DOI: 10.1021/acs.inorgchem.3c03347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Uranyl cation, as an emerging photocatalyst, has been successfully applied to synthetic chemistry in recent years and displayed remarkable catalytic ability under visible light. However, the molecular-level reaction mechanisms of uranyl photocatalysis are unclear. Here, we explore the mechanism of the stepwise benzylic C-H oxygenation of typical alkyl-substituted aromatics (i.e., toluene, ethylbenzene, and cumene) via uranyl photocatalysis using theoretical and experimental methods. Theoretical calculation results show that the most favorable reaction path for uranyl photocatalytic oxidation is as follows: first, hydrogen atom transfer (HAT) from the benzyl position to form a carbon radical ([R•]), then oxygen addition ([R•] + O2 → [ROO•]), then radical-radical combination ([ROO•] + [R•] → [ROOR] → 2[RO•]), and eventually [RO•] reduction to produce alcohols, of which 2° alcohol would further be oxidized to ketones and 1° would be stepwise-oxygenated to acids. The results of the designed verification experiments and the capture of reactive intermediates were consistent with those of theoretical calculations and the previously reported research that the active benzylic C-H would be stepwise-oxygenated in the presence of uranyl. This work deepens our understanding of the HAT mechanism of uranyl photocatalysis and provides important theoretical support for the relevant application of uranyl photocatalysts in organic transformation.
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Affiliation(s)
- Shu-Yun Zhang
- College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Song-Bai Tang
- College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Yan-Xin Jiang
- College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Ru-Yu Zhu
- College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Zi-Xin Wang
- College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Bo Long
- College of Materials Science and Engineering, Guizhou Minzu University, Guiyang 550025, P. R. China
| | - Jing Su
- College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
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Zhao Q, Wang Y, Wang Y, Hu Q, Yao J, Wen Z, Li H. Control of Selectivity in FeCl 3 -Catalyzed Aerobic Oxidation of Cycloketones. Chem Asian J 2023; 18:e202201101. [PMID: 36519526 DOI: 10.1002/asia.202201101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/12/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
The FeCl3 -catalyzed aerobic oxidation of ketones always gives rise to the α-C-C cleavage product, having challenges to afford hydroxyl keto compounds. Here we report an effective control of the main product from keto acid to α-hydroxyl ketone, by reducing the concentration of FeCl3 catalyst, together with the use of DMSO as the solvent. In addition, mechanistic investigations suggested the same FeCl3 -coordinated peroxide intermediate for both hydroxylation and C-C cleavage routes, and emphasize the role of DMSO as both ligand and reductant. This work provides a new approach for selective aerobic oxidation under Lewis acid catalysis.
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Affiliation(s)
- Qi Zhao
- Department of Chemistry and ZJU-NHU United R&D Center, Zhejiang University, Zhe Da Rd. 38, Hangzhou, 310027, P. R. China
| | - Yongtao Wang
- Department of Chemistry and ZJU-NHU United R&D Center, Zhejiang University, Zhe Da Rd. 38, Hangzhou, 310027, P. R. China
- Center of Chemistry for Frontier Technologies, Zhejiang University, Zhe Da Rd. 38, Hangzhou, 310027, P. R. China
| | - Yu Wang
- Department of Chemistry and ZJU-NHU United R&D Center, Zhejiang University, Zhe Da Rd. 38, Hangzhou, 310027, P. R. China
| | - Qixuan Hu
- Department of Chemistry and ZJU-NHU United R&D Center, Zhejiang University, Zhe Da Rd. 38, Hangzhou, 310027, P. R. China
| | - Jia Yao
- Department of Chemistry and ZJU-NHU United R&D Center, Zhejiang University, Zhe Da Rd. 38, Hangzhou, 310027, P. R. China
| | - Zeyu Wen
- Department of Chemistry and ZJU-NHU United R&D Center, Zhejiang University, Zhe Da Rd. 38, Hangzhou, 310027, P. R. China
| | - Haoran Li
- Department of Chemistry and ZJU-NHU United R&D Center, Zhejiang University, Zhe Da Rd. 38, Hangzhou, 310027, P. R. China
- State Key Laboratory of Chemical Engineering and College of Chemical and Biological Engineering, Zhejiang University, Zhe Da Rd. 38, Hangzhou, 310027, P. R. China
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Wang Y, Sun W, Lu R, Wen Z, Yao J, Li H. Inorganic Bases Enhanced Organocatalysis for Aerobic αHydroxylation of Aliphatic Cycloketones. ASIAN J ORG CHEM 2022. [DOI: 10.1002/ajoc.202200443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yongtao Wang
- Zhejiang University Department of Chemistry CHINA
| | - Wenjing Sun
- Zhejiang University Department of Chemistry CHINA
| | - Rui Lu
- Zhejiang University Department of Chemistry CHINA
| | - Zeyu Wen
- Zhejiang University Department of Chemistry CHINA
| | - Jia Yao
- Zhejiang University Department of Chemistry CHINA
| | - Haoran Li
- Zhejiang University Department of Chemistry Zheda Road 310027 Hangzhou CHINA
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Dong B, Xu G, Yang R, Wang Q. Chemical Upcycling of Poly(ε-caprolactone) to Valuable Chemical via TBD-Catalyzed Efficient Methanolysis Strategy. Chem Asian J 2022; 17:e202200667. [PMID: 35983673 DOI: 10.1002/asia.202200667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 08/01/2022] [Indexed: 11/09/2022]
Abstract
As a petroleum-derived polyester material, poly(ε-caprolactone) (PCL) plays an essential role in biomedical field due to its excellent biocompatibility and non-toxicity. With the increasing use of PCL in recent years, its waste disposal has become a significant challenge. To address this challenge, we demonstrate a high-efficiency organocatalysis strategy for the chemical upcycling of PCL to valuable chemical. Among organocatalysts explored in this article, 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) shows superior performance for transforming end-of-life poly(ε-caprolactone) into highly value-added methyl 6-hydroxyhexanoate with quantitative conversion in a short time. The endwise unzipping depolymerization mechanism is corroborated by monitoring molecular weight during depolymerization process and 1 H NMR control experiments. Furthermore, this approach is also practicable for large-scale depolymerization for commercial PCL plastics, providing idea for promoting the sustainable development of PCL plastics.
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Affiliation(s)
- Bingzhe Dong
- Qingdao Institute of BioEnergy and Bioprocess Technology Chinese Academy of Sciences, Bio-based materials, CHINA
| | - Guangqiang Xu
- Qingdao Institute of BioEnergy and Bioprocess Technology Chinese Academy of Sciences, Bio-based Materials, CHINA
| | - Rulin Yang
- Qingdao Institute of BioEnergy and Bioprocess Technology Chinese Academy of Sciences, Bio-based Materials, CHINA
| | - Qinggang Wang
- Qingdao Institute of BioEnergy and Bioprocess Technology Chinese Academy of Sciences, Bio-based Materials, Songling Road 189., 266101, Qingdao, CHINA
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