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Chen PY, Huang C, Jie LH, Guo B, Zhu S, Xu HC. Unlocking the Potential of Oxidative Asymmetric Catalysis with Continuous Flow Electrochemistry. J Am Chem Soc 2024; 146:7178-7184. [PMID: 38466344 DOI: 10.1021/jacs.4c00878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
In the field of catalytic asymmetric synthesis, the less-treated path lies in oxidative catalytic asymmetric transformations. The hurdles of pinpointing the appropriate chemical oxidants and addressing their compatibility issues with catalysts and functionalities present significant challenges. Organic electrochemistry, employing traceless electrons for redox reactions, is underscored as a promising solution. However, the commonly used electrolysis in batch cells introduces its own set of challenges, hindering the advancement of electrochemical asymmetric catalysis. Here we introduce a microfluidic electrochemistry platform with single-pass continuous flow reactors that exhibits a wide-ranging applicability to various oxidative asymmetric catalytic transformations. This is exemplified through the sulfenylation of 1,3-dicarbonyls, dehydrogenative C-C coupling, and dehydrogenative alkene annulation processes. The unique properties of microfluidic electrochemical reactors not only eliminate the need for chemical oxidants but also enhance reaction efficiency and reduce the use of additives and electrolytes. These salient features of microfluidic electrochemistry expedite the discovery and development of oxidative asymmetric transformations. In addition, the continuous production facilitated by parallel single-pass reactors ensures straightforward reaction upscaling, removing the necessity for reoptimization across various scales, as evidenced by direct translation from milligram screening to hectogram asymmetric synthesis.
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Affiliation(s)
- Peng-Yu Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - Chong Huang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - Liang-Hua Jie
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - Bin Guo
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - Shaobin Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
- NanoFCM INC., Building No. 5, Xinke Square, Xiamen 361006, People's Republic of China
| | - Hai-Chao Xu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
- Discipline of Intelligent Instrument and Equipment, Xiamen University, Xiamen 361005, People's Republic of China
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Zarfos SD, Deans BJ, Ho CC, Jordan GJ, Smith JA, Bissember AC. Distinctive Arbutin-Containing Markers: Chemotaxonomic Significance and Insights into the Evolution of Proteaceae Phytochemistry. Chem Biodivers 2023; 20:e202301112. [PMID: 37726205 DOI: 10.1002/cbdv.202301112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/17/2023] [Accepted: 09/19/2023] [Indexed: 09/21/2023]
Abstract
Natural products isolation studies of eight endemic Tasmanian Proteaceae species - Agastachys odorata, Persoonia juniperina, Hakea megadenia, Hakea epiglottis, Orites diversifolius, Orites acicularis, Orites revolutus, and Telopea truncata - and three endemic Australian Proteaceae species Banksia serrata, Banksia praemorsa, and Banksia marginata were undertaken. Two previously unreported glycoside-derived natural products were identified, in addition to four other tremendously rare arbutin esters. The results of this study provide further evidence consistent with the proposal that these distinctive arbutin esters represent markers that can provide valuable insights into the chemical evolution of plant species within the family Proteaceae.
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Affiliation(s)
- Samuel D Zarfos
- School of Natural Sciences - Chemistry, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Bianca J Deans
- School of Natural Sciences - Chemistry, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Curtis C Ho
- School of Natural Sciences - Chemistry, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Gregory J Jordan
- School of Natural Sciences - Biological Sciences, University of Tasmania, Hobart, 7001, Tasmania, Australia
| | - Jason A Smith
- School of Natural Sciences - Chemistry, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Alex C Bissember
- School of Natural Sciences - Chemistry, University of Tasmania, Hobart, Tasmania, 7001, Australia
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Chen TS, Long H, Gao Y, Xu HC. Continuous Flow Electrochemistry Enables Practical and Site-Selective C-H Oxidation. Angew Chem Int Ed Engl 2023; 62:e202310138. [PMID: 37590086 DOI: 10.1002/anie.202310138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/08/2023] [Accepted: 08/17/2023] [Indexed: 08/18/2023]
Abstract
The selective oxygenation of ubiquitous C(sp3 )-H bonds remains a highly sought-after method in both academia and the chemical industry for constructing functionalized organic molecules. However, it is extremely challenging to selectively oxidize a certain C(sp3 )-H bond to afford alcohols due to the presence of multiple C(sp3 )-H bonds with similar strength and steric environment in organic molecules, and the alcohol products being prone to further oxidation. Herein, we present a practical and cost-efficient electrochemical method for the highly selective monooxygenation of benzylic C(sp3 )-H bonds using continuous flow reactors. The electrochemical reactions produce trifluoroacetate esters that are resistant to further oxidation but undergo facile hydrolysis during aqueous workup to form benzylic alcohols. The method exhibits a broad scope and exceptional site selectivity and requires no catalysts or chemical oxidants. Furthermore, the electrochemical method demonstrates excellent scalability by producing 115 g of one of the alcohol products. The high site selectivity of the electrochemical method originates from its unique mechanism to cleave benzylic C(sp3 )-H bonds through sequential electron/proton transfer, rather than the commonly employed hydrogen atom transfer (HAT).
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Affiliation(s)
- Tian-Sheng Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Hao Long
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Yuxing Gao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Hai-Chao Xu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
- Discipline of Intelligent Instrument and Equipment, Xiamen University, Xiamen, 361005, China
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Nguyen QH, Um TW, Shin S. α-Carbonyl Radicals from N-Enoxybenzotriazoles: De Novo Synthesis of 9-Phenanthrols. Org Lett 2022; 24:8337-8342. [DOI: 10.1021/acs.orglett.2c03356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Quynh H. Nguyen
- Department of Chemistry, Research Institute for Natural Sciences and Center for New Directions in Organic Synthesis (CNOS), Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea
| | - Tae-Woong Um
- Department of Chemistry, Research Institute for Natural Sciences and Center for New Directions in Organic Synthesis (CNOS), Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea
| | - Seunghoon Shin
- Department of Chemistry, Research Institute for Natural Sciences and Center for New Directions in Organic Synthesis (CNOS), Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea
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