1
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Miyamoto Y, Murakami S, Sumida Y, Hirai G, Ohmiya H. Radical C-Glycosylation Using Photoexcitable Unprotected Glycosyl Borate. Chemistry 2024; 30:e202402256. [PMID: 38980084 DOI: 10.1002/chem.202402256] [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: 06/12/2024] [Revised: 07/08/2024] [Accepted: 07/09/2024] [Indexed: 07/10/2024]
Abstract
We have developed radical C-glycosylation using photoexcitable unprotected glycosyl borate. The direct excitation of glycosyl borate under visible light irradiation enabled the generation of anomeric radical without any photoredox catalysts. The in situ generated anomeric radical was applicable to the radical addition such as Giese-type addition and Minisci-type reaction to introduce alkyl and heteroaryl groups at the anomeric position. In addition, the radical-radical coupling between the glycosyl borate and acyl imidazolide provided unprotected acyl C-glycosides.
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Affiliation(s)
- Yusuke Miyamoto
- Institute for Chemical Research Kyoto University, 611-0011, Gokasho, Uji, Kyoto, Japan
| | - Sho Murakami
- Institute for Chemical Research Kyoto University, 611-0011, Gokasho, Uji, Kyoto, Japan
| | - Yuto Sumida
- Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 101-0062, Kanda- Surugadai, Chiyoda-ku Tokyo, Japan
| | - Go Hirai
- Graduate School of Pharmaceutical Sciences, Kyushu University, 812-8582, Maidashi, Higashiku, Fukuoka, Japan
| | - Hirohisa Ohmiya
- Institute for Chemical Research Kyoto University, 611-0011, Gokasho, Uji, Kyoto, Japan
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2
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Huang B, Zhang Z, Jiao J, Liu W, Yan X. Redox-Paired Reductive Heck Reaction and Oxidative Esterification Catalyzed by Mesoionic Carbenes. Org Lett 2024; 26:7419-7424. [PMID: 39172063 DOI: 10.1021/acs.orglett.4c02762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
Paring a reductive reaction and an oxidative reaction in one reaction could be immensely important in achieving atom economic and environmental advantages. Herein, we report a simple protocol that combines two such reductive Heck reactions and oxidative esterification by using mesoionic carbenes as catalysts to synthesize multiple valuable products under mild conditions.
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Affiliation(s)
- Benkai Huang
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, China
| | - Zengyu Zhang
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, China
| | - Jie Jiao
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, China
| | - Wei Liu
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, China
| | - Xiaoyu Yan
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, China
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3
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Zhao Y, Zhang Y, Huang Y. Enantioselective Relay Coupling of Perfluoroalkyl and Vinylogous Ketyl Radicals. Angew Chem Int Ed Engl 2024; 63:e202409566. [PMID: 38865105 DOI: 10.1002/anie.202409566] [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: 05/21/2024] [Revised: 06/12/2024] [Accepted: 06/12/2024] [Indexed: 06/13/2024]
Abstract
β-Chiral carboxylic acids and their derivatives are highly valuable structural motifs in the fields of asymmetric synthesis and medicinal chemistry. However, the introduction of a sterically demanding sidechain to the β-carbon, such as an all-carbon quaternary center, remains a significant challenge in classical polar processes. Recently, N-heterocyclic carbene (NHC) mediated coupling reactions involving persistent ketyl radicals have emerged as a promising strategy to assemble highly crowded carbon-carbon bonds. Nevertheless, achieving enantioselectivity in these reactions remains highly challenging. In this work, we report our recent progress in controlling enantioselectivity for relay coupling of perfluoroalkyl and persistent vinylogous ketyl radicals. We developed a chiral bifunctional NHC-squaramide catalyst that achieves high facial selectivity in a critical bond-forming event involving the coupling of a congested tertiary carbon radical and vinylogous ketyl radical. Chiral carboxylates bearing an all-carbon quaternary center at the β-position can be prepared in good yield and excellent enantiomeric excess. Results from density functional theory (DFT) calculations and nuclear Overhauser effect (NOE) experiments indicate that the N,N'-diaryl squaramide motif adopts an unusual syn-syn conformation, enabling hydrogen bonding interactions with the enolate oxygen, thereby rigidifying the overall conformation of the transition state.
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Affiliation(s)
- Yuxin Zhao
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Yichi Zhang
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Yong Huang
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
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4
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Lu F, Su F, Pan S, Wu X, Wu X, Chi YR. N-Heterocyclic Carbene Enabled Functionalization of Inert C(Sp 3)-H Bonds via Hydrogen Atom Transfer (HAT) Processes. Chemistry 2024; 30:e202401811. [PMID: 39092881 DOI: 10.1002/chem.202401811] [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: 05/08/2024] [Indexed: 08/04/2024]
Abstract
Developing methods to directly transform C(sp3) -H bonds is crucial in synthetic chemistry due to their prevalence in various organic compounds. While conventional protocols have largely relied on transition metal catalysis, recent advancements in organocatalysis, particularly with radical NHC catalysis have sparked interest in the direct functionalization of "inert" C(sp3) -H bonds for cross C-C coupling with carbonyl moieties. This strategy involves selective cleavage of C(sp3) -H bonds to generate key carbon radicals, often achieved via hydrogen atom transfer (HAT) processes. By leveraging the bond dissociation energy (BDE) and polarity effects, HAT enables the rapid functionalization of diverse C(sp3)-H substrates, such as ethers, amines, and alkanes. This mini-review summarizes the progress in carbene organocatalytic functionalization of inert C(sp3)-H bonds enabled by HAT processes, categorizing them into two sections: 1) C-H functionalization involving acyl azolium intermediates; and 2) functionalization of C-H bonds via reductive Breslow intermediates.
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Grants
- U23A20201, 22071036 National Natural Science Foundation of China
- 2022YFD1700300 National Key Research and Development Program of China
- (2022)47) National Natural Science Fund for Excellent Young Scientists Fund Program (Overseas)-YQHW, the starting grant of Guizhou University
- [Qiankehejichu-ZK[2024]yiban030 Science and Technology Department of Guizhou Province
- 111 Program, D20023 Program of Introducing Talents of Discipline to Universities of China (111 Program, D20023) at Guizhou University
- [Qianjiaohe KY (2020)004] Frontiers Science Center for Asymmetric Synthesis and Medicinal Molecules, Department of Education, Guizhou Province
- MOE AcRF Tier 1 Award (RG84/22, RG70/21), MOE AcRF Tier 2 (MOE-T2EP10222-0006), and MOE AcRF Tier 3 Award (MOE2018-T3-1-003) Ministry of Education, Singapore
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Affiliation(s)
- Fengfei Lu
- State Key Laboratory of Green Pesticides, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Fen Su
- State Key Laboratory of Green Pesticides, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Shijie Pan
- State Key Laboratory of Green Pesticides, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Xiuli Wu
- State Key Laboratory of Green Pesticides, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Xingxing Wu
- State Key Laboratory of Green Pesticides, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Yonggui Robin Chi
- State Key Laboratory of Green Pesticides, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
- School of Chemistry, Chemical Engineering, and Biotechnology, Nanyang Technological University, Singapore, 637371, Singapore
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5
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Kawasaki T, Tosaki T, Miki S, Takada T, Murakami M, Ishida N. Dehydrogenative Coupling of Alkylamines with Primary Alcohols Forming α-Amino Ketones. J Am Chem Soc 2024; 146:17566-17572. [PMID: 38885646 DOI: 10.1021/jacs.4c02761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Acceptorless dehydrogenative coupling reactions between C-H bonds offer straightforward and atom-economical methods connecting readily available materials while liberating gaseous hydrogen as the sole byproduct. Despite the growing interest in such transformations, their realization still poses a significant challenge. Here we report a photoinduced dehydrogenative coupling reaction of alkylamines with primary alcohols. C-H bonds adjacent to nitrogen and oxygen are site-selectively cleaved, and a C-C bond is created between the carbon atoms in a cross-selective manner to produce α-amino ketones. Diverse polar functionalities such as esters, amides, and carboxylic acids survived, demonstrating the broad applicability of the present method.
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Affiliation(s)
- Tairin Kawasaki
- Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Tomohiro Tosaki
- Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Shousuke Miki
- Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Tsuyoshi Takada
- Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Masahiro Murakami
- Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Naoki Ishida
- Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Katsura, Kyoto 615-8510, Japan
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6
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Xu J, Liu B. Metal Free Functionalization of Saturated Heterocycles with Vinylarenes and Pyridine Enabled by Photocatalytic Hydrogen Atom Transfer. Chemistry 2024; 30:e202400612. [PMID: 38566284 DOI: 10.1002/chem.202400612] [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: 02/16/2024] [Revised: 03/25/2024] [Accepted: 04/01/2024] [Indexed: 04/04/2024]
Abstract
Saturated heterocycles are important class of structural scaffolds in small-molecule drugs, natural products, and synthetic intermediates. Here, we disclosed a metal free, mild, and scalable functionalization of saturated heterocycles using vinylarenes as a linchpin approach. Key to success of this transformation is the employing of simple and cheap benzophenone as a hydrogen atom transfer (HAT) catalyst. This operationally robust process was used for the making of diverse functionalized saturated heterocycles. Furthermore, aldehydes, alkane, and alcohol have been functionalized under the optimized conditions. The potential pharmaceutical utility of the procedure has also been demonstrated by late-stage functionalization of bioactive natural compounds and pharmaceutical molecules. Initial mechanism studies and control experiments were performed to elucidate the mechanism of the reactions.
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Affiliation(s)
- Junhua Xu
- School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi, 330031, People's Republic of China
| | - Bin Liu
- School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi, 330031, People's Republic of China
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7
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Pyszka I, Jędrzejewska B. Highly Efficient Photoinitiation Systems Based on Dibenzo[a,c]phenazine Sensitivity to Visible Light for Dentistry. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2597. [PMID: 38893862 PMCID: PMC11173425 DOI: 10.3390/ma17112597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 05/20/2024] [Accepted: 05/25/2024] [Indexed: 06/21/2024]
Abstract
In this work, photoinitiation systems based on dibenzo[a,c]phenazine sensitivity to visible light were designed for their potential application in dentistry. Modification of the structure of dibenzo[a,c]phenazine consisted of introducing electron-donating and electron-withdrawing substituents and heavy atoms into position 11. The synthesized compounds are able to absorb radiation emitted by dental lamps during photoinitiation of the polymerization process. In the presence of acrylates, dibenzo[a,c]phenazines show excellent photoinitiating abilities in systems containing an electron donor or a hydrogen-atom donor as a second component. The developed systems initiate the polymerization process comparable to a commercial photoinitiator, i.e., camphorquinone. Moreover, the performed studies showed a significant shortening of the polymerization time and a reduction in the amount of light absorber. This indicates that polymeric materials are obtained at a similar rate despite a significant reduction in the concentration of the newly developed two-component photoinitiating systems.
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Affiliation(s)
- Ilona Pyszka
- Faculty of Chemical Technology and Engineering, Bydgoszcz University of Science and Technology, ul. Seminaryjna 3, 85-326 Bydgoszcz, Poland
| | - Beata Jędrzejewska
- Faculty of Chemical Technology and Engineering, Bydgoszcz University of Science and Technology, ul. Seminaryjna 3, 85-326 Bydgoszcz, Poland
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8
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Sivaraj C, Muthuvel K, Udayan AT, Premkumar E, Gandhi T. Facile Cleavage of Activated Ketones: An Access to Thioethers via In Situ Generation of Anhydrides by Pummerer-Type Rearrangement. J Org Chem 2024; 89:7020-7026. [PMID: 38664860 DOI: 10.1021/acs.joc.4c00407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Herein, we report an oxygen insertion in activated ketones from simple inorganic carbonates for the synthesis of symmetric aromatic anhydrides. For the first time, Li2CO3 acts as an oxygen source and the in situ generated symmetric aromatic anhydrides undergo Pummerer-type rearrangement to access α-benzoyloxy-thioethers. Attractively, this protocol occurs under metal-, ligand-, and oxidant-free conditions and is compatible with a wide range of substrates. Control experiments reveal the reaction pathway.
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Affiliation(s)
- Chandrasekaran Sivaraj
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore 632014, Tamil Nadu, India
| | - Karthick Muthuvel
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore 632014, Tamil Nadu, India
| | - Ajay Thonipalliyalil Udayan
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore 632014, Tamil Nadu, India
| | - Egambaram Premkumar
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore 632014, Tamil Nadu, India
| | - Thirumanavelan Gandhi
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore 632014, Tamil Nadu, India
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9
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Pyszka I, Jędrzejewska B. Design of Dyes Based on the Quinoline or Quinoxaline Skeleton towards Visible Light Photoinitiators. Int J Mol Sci 2024; 25:4289. [PMID: 38673872 PMCID: PMC11050332 DOI: 10.3390/ijms25084289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 04/09/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
Dyes based on quinoline and quinoxaline skeletons were designed for application as visible light photoinitiators. The obtained compounds absorb electromagnetic radiation on the border between ultraviolet and visible light, which allows the use of dental lamps as light sources during the initiation of the photopolymerization reaction. Their another desirable feature is the ability to create a long-lived excited state, which enables the chain reaction to proceed through the mechanism of intermolecular electron transfer. In two-component photoinitiating systems, in the presence of an electron donor or a hydrogen atom donor, the synthesized compounds show excellent abilities to photoinitiate the polymerization of acrylates. In control tests, the efficiency of photopolymerization using modified quinoline and quinoxaline derivatives is comparable to that obtained using a typical, commercial photoinitiator for dentistry, camphorquinone. Moreover, the use of the tested compounds requires a small amount of photoinitiator (only 0.04% by weight) to initiate the reaction. The research also showed a significant acceleration of the photopolymerization process and shortening of the reaction time. In practice, this means that the new two-component initiating systems can be used in much lower concentrations without slowing down the speed of obtaining polymer materials. It is worth emphasizing that these two features of the new initiating system allow for cost reduction by reducing financial outlays on both materials (photoinitiators) and electricity.
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Affiliation(s)
- Ilona Pyszka
- Faculty of Chemical Technology and Engineering, Bydgoszcz University of Science and Technology, Ul. Seminaryjna 3, 85-326 Bydgoszcz, Poland;
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10
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Kim SF, Schwarz H, Jurczyk J, Nebgen BR, Hendricks H, Park H, Radosevich A, Zuerch MW, Harper K, Lux MC, Yeung CS, Sarpong R. Mechanistic Investigation, Wavelength-Dependent Reactivity, and Expanded Reactivity of N-Aryl Azacycle Photomediated Ring Contractions. J Am Chem Soc 2024; 146:5580-5596. [PMID: 38347659 DOI: 10.1021/jacs.3c13982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Under mild blue-light irradiation, α-acylated saturated heterocycles undergo a photomediated one-atom ring contraction that extrudes a heteroatom from the cyclic core. However, for nitrogenous heterocycles, this powerful skeletal edit has been limited to substrates bearing electron-withdrawing substituents on nitrogen. Moreover, the mechanism and wavelength-dependent efficiency of this transformation have remained unclear. In this work, we increased the electron richness of nitrogen in saturated azacycles to improve light absorption and strengthen critical intramolecular hydrogen bonding while enabling the direct installation of the photoreactive handle. As a result, a broadly expanded substrate scope, including underexplored electron-rich substrates and previously unsuccessful heterocycles, has now been achieved. The significantly improved yields and diastereoselectivities have facilitated reaction rate, kinetic isotope effect (KIE), and quenching studies, in addition to the determination of quantum yields. Guided by these studies, we propose a revised ET/PT mechanism for the ring contraction, which is additionally corroborated by computational characterization of the lowest-energy excited states of α-acylated substrates through time-dependent DFT. The efficiency of the ring contraction at wavelengths longer than those strongly absorbed by the substrates was investigated through wavelength-dependent rate measurements, which revealed a red shift of the photochemical action plot relative to substrate absorbance. The elucidated mechanistic and photophysical details effectively rationalize empirical observations, including additive effects, that were previously poorly understood. Our findings not only demonstrate enhanced synthetic utility of the photomediated ring contraction and shed light on mechanistic details but may also offer valuable guidance for understanding wavelength-dependent reactivity for related photochemical systems.
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Affiliation(s)
- Sojung F Kim
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Henrik Schwarz
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Justin Jurczyk
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Bailey R Nebgen
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
- Lawrence Berkeley National Laboratory, Materials Sciences Division, Berkeley, California 94720, United States
| | - Hailey Hendricks
- Department of Discovery Chemistry, Merck & Co., Inc., Boston, Massachusetts 02115, United States
| | - Hojoon Park
- Department of Process Research and Development, Merck & Co., Inc., Boston, Massachusetts 02115, United States
| | - Andrew Radosevich
- Small Molecule Therapeutics & Platform Technologies, Abbvie Inc., North Chicago, Illinois 60064, United States
| | - Michael W Zuerch
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
- Lawrence Berkeley National Laboratory, Materials Sciences Division, Berkeley, California 94720, United States
| | - Kaid Harper
- Process Chemistry, Abbvie Inc., North Chicago, Illinois 60064, United States
| | - Michaelyn C Lux
- Department of Discovery Chemistry, Merck & Co., Inc., Boston, Massachusetts 02115, United States
| | - Charles S Yeung
- Department of Discovery Chemistry, Merck & Co., Inc., Boston, Massachusetts 02115, United States
| | - Richmond Sarpong
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
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11
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Sivaraj C, Maiti D, Gandhi T. Photo-Catalyzed Acyl Azolium Promoted Selective α-C(sp 3 )-H Acylation of Acetone via HAT: Access to Thermodynamically Less Favoured (Z)-α,β-Unsaturated Ketones. Chemistry 2024; 30:e202303626. [PMID: 37997552 DOI: 10.1002/chem.202303626] [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: 11/02/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 11/25/2023]
Abstract
Mono α-acylation of acetone has been achieved for the first time by reacting with bench-stable acyl azolium salts under violet-LED light at room temperature. The intermolecular hydrogen atom transfer (HAT) from acetone to triplet state of azolium salts under violet LED irradiation resulted in thermodynamically less favourable (Z)-α,β-unsaturated ketones with up to 99 : 1 selectivity via C-C bond formation. This compelling protocol access the desired α-C(sp3 )-H acylation product under metal-, ligand- and oxidant-free conditions on a wide range of substrates.
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Affiliation(s)
- Chandrasekaran Sivaraj
- Department of Chemistry, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India
| | - Debabrata Maiti
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Thirumanavelan Gandhi
- Department of Chemistry, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India
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12
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Xia J, Guo Y, Lv Z, Sun J, Zheng G, Zhang Q. Visible Light-Mediated Monofluoromethylation/Acylation of Olefins by Dual Organo-Catalysis. Molecules 2024; 29:790. [PMID: 38398543 PMCID: PMC10892033 DOI: 10.3390/molecules29040790] [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: 12/31/2023] [Revised: 02/01/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Monofluoromethyl (CH2F) motifs exhibit unique bioactivities and are considered privileged units in drug discovery. The radical monofluoromethylative difunctionalization of alkenes stands out as an appealing approach to access CH2F-containing compounds. However, this strategy remains largely underdeveloped, particularly under metal-free conditions. In this study, we report on visible light-mediated three-component monofluoromethylation/acylation of styrene derivatives employing NHC and organic photocatalyst dual catalysis. A diverse array of α-aryl-β-monofluoromethyl ketones was successfully synthesized with excellent functional group tolerance and selectivity. The mild and metal-free CH2F radical generation strategy from NaSO2CFH2 holds potential for further applications in fluoroalkyl radical chemistry.
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Affiliation(s)
- Jiuli Xia
- Key Laboratory of Functional Organic Molecule Design & Synthesis of Jilin Province, Department of Chemistry, Northeast Normal University, Changchun 130024, China; (J.X.); (Z.L.); (Q.Z.)
| | - Yunliang Guo
- School of Environment, Northeast Normal University, Changchun 130117, China;
| | - Zhiguang Lv
- Key Laboratory of Functional Organic Molecule Design & Synthesis of Jilin Province, Department of Chemistry, Northeast Normal University, Changchun 130024, China; (J.X.); (Z.L.); (Q.Z.)
| | - Jiaqiong Sun
- School of Environment, Northeast Normal University, Changchun 130117, China;
| | - Guangfan Zheng
- Key Laboratory of Functional Organic Molecule Design & Synthesis of Jilin Province, Department of Chemistry, Northeast Normal University, Changchun 130024, China; (J.X.); (Z.L.); (Q.Z.)
| | - Qian Zhang
- Key Laboratory of Functional Organic Molecule Design & Synthesis of Jilin Province, Department of Chemistry, Northeast Normal University, Changchun 130024, China; (J.X.); (Z.L.); (Q.Z.)
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
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13
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Dutta S, Kim JH, Bhatt K, Rickertsen DRL, Abboud KA, Ghiviriga I, Seidel D. Alicyclic-Amine-Derived Imine-BF 3 Complexes: Easy-to-Make Building Blocks for the Synthesis of Valuable α-Functionalized Azacycles. Angew Chem Int Ed Engl 2024; 63:e202313247. [PMID: 37909921 PMCID: PMC10835740 DOI: 10.1002/anie.202313247] [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: 09/06/2023] [Revised: 10/26/2023] [Accepted: 10/29/2023] [Indexed: 11/03/2023]
Abstract
A new strategy to access α-functionalized alicyclic amines via their corresponding imine-BF3 complexes is reported. Isolable imine-BF3 complexes, readily prepared via dehydrohalogenation of N-bromoamines in a base-promoted/18-crown-6 catalyzed process followed by addition of boron trifluoride etherate, undergo reactions with a wide range of organometallic nucleophiles to afford α-functionalized azacycles. Organozinc and organomagnesium nucleophiles add at ambient temperatures, obviating the need for cryogenic conditions. In situ preparation of imine-BF3 complexes provides access to α-functionalized morpholines and piperazines directly from their parent amines in a single operation. α-Functionalized morpholines can be elaborated further, for instance by installing a second substituent in the α'-position.
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Affiliation(s)
- Subhradeep Dutta
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Jae Hyun Kim
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
- College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Kamal Bhatt
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Dillon R L Rickertsen
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Khalil A Abboud
- Center for X-ray Crystallography, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Ion Ghiviriga
- Center for NMR Spectroscopy, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Daniel Seidel
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
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14
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Cao J, Zhu JL, Scheidt KA. Photoinduced cerium-catalyzed C-H acylation of unactivated alkanes. Chem Sci 2023; 15:154-159. [PMID: 38131082 PMCID: PMC10732008 DOI: 10.1039/d3sc05162e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 11/09/2023] [Indexed: 12/23/2023] Open
Abstract
Ketones are ubiquitous motifs in the realm of pharmaceuticals and natural products. Traditional approaches to accessing these species involve the addition of metal reagents to carboxyl compounds under harsh conditions. Herein, we report a cerium-catalyzed acylation of unactivated C(sp3)-H bonds using bench-stable acyl azolium reagents under mild and operationally-friendly conditions. This reaction exhibits excellent generality, accommodating a wide range of feedstock chemicals such as cycloalkanes and acyclic compounds as well as facilitating the late-stage functionalization of pharmaceuticals. We demonstrate further applications of our strategy with a three-component radical relay reaction and an enantioselective N-heterocyclic carbene (NHC) and cerium dual-catalyzed reaction.
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Affiliation(s)
- Jing Cao
- Department of Chemistry, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Joshua L Zhu
- Department of Chemistry, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Karl A Scheidt
- Department of Chemistry, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
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15
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Byun S, Hwang MU, Wise HR, Bay AV, Cheong PHY, Scheidt KA. Light-Driven Enantioselective Carbene-Catalyzed Radical-Radical Coupling. Angew Chem Int Ed Engl 2023; 62:e202312829. [PMID: 37845183 PMCID: PMC10841513 DOI: 10.1002/anie.202312829] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/13/2023] [Accepted: 10/13/2023] [Indexed: 10/18/2023]
Abstract
An enantioselective carbene-catalyzed radical-radical coupling of acyl imidazoles and racemic Hantzsch esters is disclosed. This method involves the coupling of an N-heterocyclic carbene-derived ketyl radical and a secondary sp3 -carbon radical and allows access to chiral α-aryl aliphatic ketones in moderate-to-good yields and enantioselectivities without any competitive epimerization. The utility of this protocol is highlighted by the late-stage functionalization of various pharmaceutical compounds and is further demonstrated by the transformation of the enantioenriched products to biologically relevant molecules. Computational investigations reveal the N-heterocyclic carbene controls the double-facial selectivity of the ketyl radical and the alkyl radicals, respectively.
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Affiliation(s)
- Seunghwan Byun
- Department of Chemistry, Northwestern University Silverman Hall, Evanston, Illinois 60208 (USA)
| | - Meemie U. Hwang
- Department of Chemistry, Northwestern University Silverman Hall, Evanston, Illinois 60208 (USA)
| | - Henry R. Wise
- Department of Chemistry, Oregon State University 153 Gilbert Hall, Corvallis, Oregon 97331 (USA)
| | - Anna V. Bay
- Department of Chemistry, Northwestern University Silverman Hall, Evanston, Illinois 60208 (USA)
| | - Paul H.-Y. Cheong
- Department of Chemistry, Oregon State University 153 Gilbert Hall, Corvallis, Oregon 97331 (USA)
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16
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Su F, Lu F, Tang K, Lv X, Luo Z, Che F, Long H, Wu X, Chi YR. Organocatalytic C-H Functionalization of Simple Alkanes. Angew Chem Int Ed Engl 2023; 62:e202310072. [PMID: 37731165 DOI: 10.1002/anie.202310072] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 09/22/2023]
Abstract
The direct functionalization of inert C(sp3 )-H bonds to form carbon-carbon and carbon-heteroatom bonds offers vast potential for chemical synthesis and therefore receives increasing attention. At present, most successes come from strategies using metal catalysts/reagents or photo/electrochemical processes. The use of organocatalysis for this purpose remains scarce, especially when dealing with challenging C-H bonds such as those from simple alkanes. Here we disclose the first organocatalytic direct functionalization/acylation of inert C(sp3 )-H bonds of completely unfunctionalized alkanes. Our approach involves N-heterocyclic carbene catalyst-mediated carbonyl radical intermediate generation and coupling with simple alkanes (through the corresponding alkyl radical intermediates generated via a hydrogen atom transfer process). Unreactive C-H bonds are widely present in fossil fuel feedstocks, commercially important organic polymers, and complex molecules such as natural products. Our present study shall inspire a new avenue for quick functionalization of these molecules under the light- and metal-free catalytic conditions.
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Affiliation(s)
- Fen Su
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Fengfei Lu
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Kun Tang
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Xiaokang Lv
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Zhongfu Luo
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Fengrui Che
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Hongyan Long
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Xingxing Wu
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
| | - Yonggui Robin Chi
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang, 550025, China
- School of chemistry, chemical engineering, and biotechnology, Nanyang Technological University, Singapore, 637371, Singapore
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17
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Rourke MJ, McGill MJ, Yang D, Farnam EJ, Zhu JL, Scheidt KA. Photoredox-Catalyzed Radical-Radical Coupling of Potassium Trifluoroborates with Acyl Azoliums. Synlett 2023; 34:2175-2180. [PMID: 38948905 PMCID: PMC11210951 DOI: 10.1055/s-0041-1738448] [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] [Indexed: 07/02/2024]
Abstract
Potassium trifluoroborates have gained significant utility as coupling partners in organic synthesis, particularly in the Suzuki-Miyaura coupling reaction. Recently, they have also been used as radical precursors under oxidative conditions to generate carbon-centered radicals. These versatile reagents have found new applications in photoredox catalysis, including radical substitution, conjugate addition reactions, and transition metal dual catalysis. In addition, this photomediated redox neutral process has enabled radical-radical coupling with persistent radicals in the absence of a metal, and this process remains to be fully explored. In this study, we report the radical-radical coupling of benzylic potassium trifluoroborate salts with isolated acyl azolium triflates, which are persistent radical precursors. The reaction is catalyzed by an organic photocatalyst and forms isolable tertiary alcohol species. These compounds can be transformed into a range of substituted ketone products by simple treatment with a mild base.
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Affiliation(s)
- Michael J. Rourke
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (USA
| | - Matthew J. McGill
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (USA
| | - Daniel Yang
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (USA
| | - Emelia J. Farnam
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (USA
| | - Joshua L. Zhu
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (USA
| | - Karl A. Scheidt
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (USA
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18
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Chen M, Ventura AM, Das S, Ibrahim AF, Zimmerman PM, Montgomery J. Oxidative Cross Dehydrogenative Coupling of N-Heterocycles with Aldehydes through C( sp3)-H Functionalization. J Am Chem Soc 2023; 145:20176-20181. [PMID: 37672664 PMCID: PMC10915535 DOI: 10.1021/jacs.3c06532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
Existing methodologies for metal-catalyzed cross-couplings typically rely on preinstallation of reactive functional groups on both reaction partners. In contrast, C-H functionalization approaches offer promise in simplification of the requisite substrates; however, challenges from low reactivity and similar reactivity of various C-H bonds introduce considerable complexity. Herein, the oxidative cross dehydrogenative coupling of α-amino C(sp3)-H bonds and aldehydes to produce ketone derivatives is described using an unusual reaction medium that incorporates the simultaneous use of di-tert-butyl peroxide as an oxidant and zinc metal as a reductant. The method proceeds with a broad substrate scope, representing an attractive approach for accessing α-amino ketones through the formal acylation of C-H bonds α to nitrogen in N-heterocycles. A combination of experimental investigation and computational modeling provides evidence for a mechanistic pathway involving cross-selective nickel-mediated cross-coupling of α-amino radicals and acyl radicals.
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Affiliation(s)
- Mo Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Austin M Ventura
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Soumik Das
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Ammar F Ibrahim
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Paul M Zimmerman
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - John Montgomery
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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19
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Li S, Zheng C, Wang S, Li XX, Zhang Q, Fan S, Feng YS. Ketone Synthesis via Irradiation-Induced Generation of a Persistent Ketyl Radical from Acyl Azolium Salts. Org Lett 2023; 25:6522-6527. [PMID: 37642302 DOI: 10.1021/acs.orglett.3c02300] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
A novel three-component α-acylated difunctionalization of alkenes strategy has been developed on the basis of a direct hydrogen atom transfer (HAT) process of photoinduced acyl azolium salts. With simple irradiation without the catalyst, a variety of olefins can be directly converted into ketone derivatives, including 1,4-dione, β-silyl ketone, 1,5-dione, etc. Mechanistic investigations indicated that the unique reactivity of the acyl azonium triplet excited state is crucial to the strategy's success.
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Affiliation(s)
- Shihao Li
- School of Chemistry and Chemical Engineering, Hefei University of Technology, 193 Tunxi Road, Anhui 230000, China
| | - Chenglong Zheng
- School of Chemistry and Chemical Engineering, Hefei University of Technology, 193 Tunxi Road, Anhui 230000, China
| | - Sheng Wang
- School of Chemistry and Chemical Engineering, Hefei University of Technology, 193 Tunxi Road, Anhui 230000, China
| | - Xiao-Xuan Li
- School of Chemistry and Chemical Engineering, Hefei University of Technology, 193 Tunxi Road, Anhui 230000, China
- Anhui Province Key Laboratory of Advance Catalytic Materials and Reaction Engineering, Hefei 230009, P. R. China
| | - Qi Zhang
- Institute of Industry & Equipment Technology, Hefei University of Technology, Hefei 230009, China
| | - Shilu Fan
- School of Chemistry and Chemical Engineering, Hefei University of Technology, 193 Tunxi Road, Anhui 230000, China
- Anhui Province Key Laboratory of Advance Catalytic Materials and Reaction Engineering, Hefei 230009, P. R. China
| | - Yi-Si Feng
- School of Chemistry and Chemical Engineering, Hefei University of Technology, 193 Tunxi Road, Anhui 230000, China
- Anhui Province Key Laboratory of Advance Catalytic Materials and Reaction Engineering, Hefei 230009, P. R. China
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20
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Peng Q, Gogoi AR, Rentería-Gómez Á, Gutierrez O, Scheidt KA. Visible-light-induced coupling of carboxylic acids with alcohols/amines via a phosphorous linchpin strategy. Chem 2023; 9:1983-1993. [PMID: 37547627 PMCID: PMC10399973 DOI: 10.1016/j.chempr.2023.04.011] [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] [Indexed: 08/08/2023]
Abstract
The combination of activated carboxylic acids and alcohols/amines to access esters and amides, respectively, is a cornerstone of organic chemistry and has been well developed over the past century. These dehydrations are extensively used in medicinal chemistry and natural product synthesis due to the prevalence of these functional groups in bioactive molecules. Here, we report a divergent process from the expected ester/amide outcomes through a light-induced coupling of activated carboxylic acids and alcohols/amines to efficiently prepare α-hydroxy/amino ketones or β-ketophosphonates via single-electron chemistry. A phosphorus linchpin strategy allows for the combination of these simple reagents through an intramolecular triplet state radical process, thereby enabling new carbon-carbon bond formation.
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Affiliation(s)
- Qiupeng Peng
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Achyut Ranjan Gogoi
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA
| | - Ángel Rentería-Gómez
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA
| | - Osvaldo Gutierrez
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA
| | - Karl A. Scheidt
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
- Lead contact
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21
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Rourke MJ, Wang CT, Schull CR, Scheidt KA. Acyl Azolium-Photoredox-Enabled Synthesis of β-Keto Sulfides. ACS Catal 2023; 13:7987-7994. [PMID: 37969469 PMCID: PMC10651059 DOI: 10.1021/acscatal.3c01558] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
α-Heteroatom functionalization is a key strategy for C-C bond formation in organic synthesis, as exemplified by the addition of a nucleophile to electrophilic functional groups, such as iminium ions; oxocarbenium ions; and their sulfur analogues, sulfenium ions. We envisioned a photoredox-enabled radical Pummerer-type reaction realized through the single-electron oxidation of a sulfide. Following this oxidative event, α-deprotonation would afford α-thio radicals that participate in radical-radical coupling reactions with azolium-bound ketyl radicals, thereby accessing a commonly proposed mechanistic intermediate of the radical-radical coupling en route to functionalized additive Pummerer products. This system provides a complementary synthetic approach to highly functionalized sulfurous products, including modification of methionine residues in peptides, and beckons further exploration in C-C bond formations previously limited in the standard two-electron process.
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Affiliation(s)
- Michael J Rourke
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Charles T Wang
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Cullen R Schull
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Karl A Scheidt
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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22
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Mavroskoufis A, Lohani M, Weber M, Hopkinson MN, Götze JP. A (TD-)DFT study on photo-NHC catalysis: photoenolization/Diels-Alder reaction of acid fluorides catalyzed by N-heterocyclic carbenes. Chem Sci 2023; 14:4027-4037. [PMID: 37063806 PMCID: PMC10094231 DOI: 10.1039/d2sc04732b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 03/14/2023] [Indexed: 03/17/2023] Open
Abstract
A comprehensive mechanistic study on the N-heterocyclic carbene (NHC) catalyzed photoenolization/Diels-Alder (PEDA) reaction of acid fluorides was performed in the framework of (time-dependent) density functional theory ((TD)-DFT). The 1,5-hydrogen atom transfer (1,5-HAT) during photoenolization of an ortho-toluoyl azolium salt was found to be feasible via, first, singlet excitation and photoenolization, and then, after crossing to the triplet manifold, populating a biradical dienol which allows for the formation of two ortho-quinodimethane (o-QDM) isomers due to a low rotational barrier. The (Z)-isomer is mostly unproductive through sigmatropic rearrangement back to the starting material while the (E)-isomer reacts in a subsequent concerted Diels-Alder reaction likely as the deprotonated dienolate. The experimentally observed diastereoselectivity is correctly predicted by theory and is determined by a more favorable endo trajectory in the cycloaddition step. These findings demonstrate that ortho-toluoyl azolium species exhibit similar photophysical properties as structurally related benzophenones, highlighting the unique ability of the NHC organocatalyst to transiently alter the excited state properties of an otherwise photoinactive carboxylic acid derivative, thereby expanding the scope of classical carbonyl photochemistry.
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Affiliation(s)
- Andreas Mavroskoufis
- Institut für Chemie und Biochemie, Freie Universität Berlin Fabeckstrasse 34-36 14195 Berlin Germany
| | - Manish Lohani
- Institut für Chemie und Biochemie, Freie Universität Berlin Arnimallee 22 14195 Berlin Germany
| | - Manuela Weber
- Institut für Chemie und Biochemie, Freie Universität Berlin Fabeckstrasse 34-36 14195 Berlin Germany
| | - Matthew N Hopkinson
- Institut für Chemie und Biochemie, Freie Universität Berlin Fabeckstrasse 34-36 14195 Berlin Germany
- School of Natural and Environmental Sciences, Newcastle University Bedson Building Newcastle upon Tyne NE1 7RU UK
| | - Jan P Götze
- Institut für Chemie und Biochemie, Freie Universität Berlin Arnimallee 22 14195 Berlin Germany
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23
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Wang L, Sun J, Xia J, Ma R, Zheng G, Zhang Q. Visible light-mediated NHC and photoredox co-catalyzed 1,2-sulfonylacylation of allenes via acyl and allyl radical cross-coupling. Org Chem Front 2023. [DOI: 10.1039/d2qo01993k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Visible light-mediated NHC and photoredox co-catalyzed radical 1,2-sulfonylacylation of allenes via cross-coupling between an allyl radical and an NHC-stabilized acyl radical.
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Affiliation(s)
- Lihong Wang
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Department of ChemistryNortheast Normal University, Changchun 130024, China
| | - Jiaqiong Sun
- School of Environment, Northeast Normal University, Changchun 130117, China
| | - Jiuli Xia
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Department of ChemistryNortheast Normal University, Changchun 130024, China
| | - Ruiyang Ma
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Department of ChemistryNortheast Normal University, Changchun 130024, China
| | - Guangfan Zheng
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Department of ChemistryNortheast Normal University, Changchun 130024, China
| | - Qian Zhang
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Department of ChemistryNortheast Normal University, Changchun 130024, China
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China
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