1
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Kaur M, Cooper JC, Van Humbeck JF. Site-selective benzylic C-H hydroxylation in electron-deficient azaheterocycles. Org Biomol Chem 2024; 22:4888-4894. [PMID: 38819259 DOI: 10.1039/d4ob00268g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
Benzylic C-H bonds can be converted into numerous functional groups, often by mechanisms that involve hydrogen atom transfer as the key bond breaking step. The abstracting species is most often an electrophilic radical, which makes these reactions best suited to electron-rich C-H bonds to achieve appropriate polarity matching. Thus, electron deficient systems such as pyridine and pyrimidine are relatively unreactive, and therefore underrepresented in substrate scopes. In this report, we describe a new method for heterobenzylic hydroxylation-essentially an unknown reaction in the case of pyrimidines-that makes use of an iodine(III) reagent to afford very high selectivity towards electron-deficient azaheterocycles in substrates with more than one reactive position and prevents over-oxidation to carbonyl products. The identification of key reaction byproducts supports a mechanism that involves radical coupling in the bond forming step.
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Affiliation(s)
- Milanpreet Kaur
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta, T2N 1N4, Canada.
| | - Julian C Cooper
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Jeffrey F Van Humbeck
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta, T2N 1N4, Canada.
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2
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Wang W, Qin Z, Zhang X, Zhao W, Yang W. Catalyst-free C(sp 3)-H functionalization of methyl azaarenes with heteroaromatic trifluoromethyl ketone hydrates: "all-water" synthesis of α-trifluoromethyl tertiary alcohols. Org Biomol Chem 2023; 21:4304-4308. [PMID: 37161518 DOI: 10.1039/d3ob00566f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
An efficient catalyst-free C(sp3)-H bond functionalization of methyl azaarenes with heteroaromatic trifluoromethyl ketone hydrates in neat water has been developed for the synthesis of α-trifluoromethyl tertiary alcohols bearing N-heteroaromatics. This method not only features excellent efficiency, broad substrate scope, catalyst-free conditions, and easy gram-scale preparation but also represents a new and rare example of "all-water" synthesis of trifluoromethylated molecules.
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Affiliation(s)
- Wei Wang
- Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China.
| | - Zhaoliang Qin
- Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China.
| | - Xinhui Zhang
- Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China.
| | - Wanxiang Zhao
- Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China.
| | - Wen Yang
- Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, P. R. China.
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3
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Quinoxaline-specific enantioselective sulfa-michael reaction catalyzed by chiral phosphoric acid. CHINESE CHEM LETT 2023. [DOI: 10.1016/j.cclet.2023.108145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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4
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Kim M, You E, Kim J, Hong S. Site-Selective Pyridylic C-H Functionalization by Photocatalytic Radical Cascades. Angew Chem Int Ed Engl 2022; 61:e202204217. [PMID: 35481719 DOI: 10.1002/anie.202204217] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Indexed: 11/08/2022]
Abstract
An efficient pyridylic C(sp3 )-H functionalization has been developed through photocatalytic radical-mediated fluoroalkylation or cascade reactions. This method is enabled by the reversible formation of alkylidene dihydropyridine intermediates via the facile enolate formation of C4-alkyl N-amidopyridinium salts in the absence of an external base, thereby establishing the conditions necessary for subsequent intermolecular radical trapping. Rapid structural diversification of the pyridylic site can be achieved through photocatalytic multicomponent cascade reactions involving alkene trifluoromethylation, SO2 -reincorporation, and sulfonyl radical addition. This operationally simple method features a broad substrate scope and high chemoselectivity and offers a unique approach for the rational modification of the heterobenzylic C-H bonds of pyridines and quinolines with uniform site-selective control. Furthermore, experimental and theoretical studies were performed to elucidate the reaction mechanism.
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Affiliation(s)
- Myojeong Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
| | - Euna You
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
| | - Jieun Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
| | - Sungwoo Hong
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
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5
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Golden DL, Suh SE, Stahl SS. Radical C(sp3)–H functionalization and cross-coupling reactions. Nat Rev Chem 2022; 6:405-427. [DOI: 10.1038/s41570-022-00388-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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6
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Kim M, You E, Kim J, Hong S. Site‐Selective Pyridylic C–H Functionalization by Photocatalytic Radical Cascades. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202204217] [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)
- Myojeong Kim
- KAIST: Korea Advanced Institute of Science and Technology Chemistry KOREA, REPUBLIC OF
| | - Euna You
- KAIST: Korea Advanced Institute of Science and Technology Chemistry KOREA, REPUBLIC OF
| | - Jieun Kim
- KAIST: Korea Advanced Institute of Science and Technology Chemistry KOREA, REPUBLIC OF
| | - Sungwoo Hong
- Korea Advanced Institute of Science and Technology KAIST Department of Chemistry Yusung Gu (KAIST) 34141 Daejeon KOREA, REPUBLIC OF
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7
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Kato T, Maruoka K. Selective functionalization of benzylic C-H bonds of two different benzylic ethers by bowl-shaped N-hydroxyimide derivatives as efficient organoradical catalysts. Chem Commun (Camb) 2021; 58:1021-1024. [PMID: 34951412 DOI: 10.1039/d1cc06425h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A highly efficient, site-selective benzylic C-H bond amination of two different benzylic ether substrates was described by using bowl-shaped N-hydroxyimide organoradical catalysts with diethyl azodicarboxylate. The synthetic utility of this approach is demonstrated by the subsequent transformation of the amination products into the corresponding aldehydes and alkylhydrazines.
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Affiliation(s)
- Terumasa Kato
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China.,Guangdong Provincial Key Laboratory of Plant Resources Biorefinery, Guangdong University of Technology, Guangzhou 510006, China.,Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan.
| | - Keiji Maruoka
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China.,Guangdong Provincial Key Laboratory of Plant Resources Biorefinery, Guangdong University of Technology, Guangzhou 510006, China.,Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan.
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8
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Wu F, Ariyarathna JP, Kaur N, Alom NE, Kennell ML, Bassiouni OH, Li W. Halogen-Bond-Induced Consecutive Csp3–H Aminations via Hydrogen Atom Transfer Relay Strategy. Org Lett 2020; 22:2135-2140. [PMID: 32109065 DOI: 10.1021/acs.orglett.0c00081] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Fan Wu
- Department of Chemistry and Biochemistry, School of Green Chemistry and Engineering, The University of Toledo, 2801 West Bancroft Street, Toledo, Ohio 43606, United States
| | - Jeewani P. Ariyarathna
- Department of Chemistry and Biochemistry, School of Green Chemistry and Engineering, The University of Toledo, 2801 West Bancroft Street, Toledo, Ohio 43606, United States
| | - Navdeep Kaur
- Department of Chemistry and Biochemistry, School of Green Chemistry and Engineering, The University of Toledo, 2801 West Bancroft Street, Toledo, Ohio 43606, United States
| | - Nur-E Alom
- Department of Chemistry and Biochemistry, School of Green Chemistry and Engineering, The University of Toledo, 2801 West Bancroft Street, Toledo, Ohio 43606, United States
| | - Maureen L. Kennell
- Department of Chemistry and Biochemistry, School of Green Chemistry and Engineering, The University of Toledo, 2801 West Bancroft Street, Toledo, Ohio 43606, United States
| | - Omar H. Bassiouni
- Department of Chemistry and Biochemistry, School of Green Chemistry and Engineering, The University of Toledo, 2801 West Bancroft Street, Toledo, Ohio 43606, United States
| | - Wei Li
- Department of Chemistry and Biochemistry, School of Green Chemistry and Engineering, The University of Toledo, 2801 West Bancroft Street, Toledo, Ohio 43606, United States
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9
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Chen AD, Herbort JH, Wappes EA, Nakafuku KM, Mustafa DN, Nagib DA. Radical cascade synthesis of azoles via tandem hydrogen atom transfer. Chem Sci 2020; 11:2479-2486. [PMID: 34084413 PMCID: PMC8157396 DOI: 10.1039/c9sc06239d] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/24/2020] [Indexed: 12/12/2022] Open
Abstract
A radical cascade strategy for the modular synthesis of five-membered heteroarenes (e.g. oxazoles, imidazoles) from feedstock reagents (e.g. alcohols, amines, nitriles) has been developed. This double C-H oxidation is enabled by in situ generated imidate and acyloxy radicals, which afford regio- and chemo-selective β C-H bis-functionalization. The broad synthetic utility of this tandem hydrogen atom transfer (HAT) approach to access azoles is included, along with experiments and computations that provide insight into the selectivity and mechanism of both HAT events.
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Affiliation(s)
- Andrew D Chen
- Department of Chemistry and Biochemistry, The Ohio State University Columbus OH 43210 USA
| | - James H Herbort
- Department of Chemistry and Biochemistry, The Ohio State University Columbus OH 43210 USA
| | - Ethan A Wappes
- Department of Chemistry and Biochemistry, The Ohio State University Columbus OH 43210 USA
| | - Kohki M Nakafuku
- Department of Chemistry and Biochemistry, The Ohio State University Columbus OH 43210 USA
| | - Darsheed N Mustafa
- Department of Chemistry and Biochemistry, The Ohio State University Columbus OH 43210 USA
| | - David A Nagib
- Department of Chemistry and Biochemistry, The Ohio State University Columbus OH 43210 USA
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10
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Kaur M, Van Humbeck JF. Recent trends in catalytic sp 3 C-H functionalization of heterocycles. Org Biomol Chem 2020; 18:606-617. [PMID: 31912069 DOI: 10.1039/c9ob01559k] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Heterocycles are a ubiquitous substructure in organic small molecules designed for use in materials and medicines. Recent work in catalysis has focused on enabling access to new heterocycle structures by sp3 C-H functionalization on alkyl side-chain substituents-especially at the heterobenzylic position-with more than two hundred manuscripts published just within the last ten years. Rather than describing in detail each of these reports, in this mini-review we attempt to highlight gaps in existing techniques. A semi-quantitative overview of ongoing work strongly suggests that several specific heterocycle types and bond formations outside of C-C, C-N, and C-O have been almost completely overlooked.
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Affiliation(s)
- Milanpreet Kaur
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4.
| | - Jeffrey F Van Humbeck
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4.
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11
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Sadamitsu Y, Saito K, Yamada T. Stereoselective amination via vinyl-silver intermediates derived from silver-catalyzed carboxylative cyclization of propargylamine. Chem Commun (Camb) 2020; 56:9517-9520. [DOI: 10.1039/d0cc02273j] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The stereoselective synthesis of aminovinyloxazolidinones based on the electrophilic amination of a vinyl-silver intermediate, generated by silver-catalyzed carbon dioxide incorporation on a propargylamine, was achieved.
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Affiliation(s)
- Yuta Sadamitsu
- Department of Chemistry
- Keio University
- Yokohama 223-8522
- Japan
| | - Kodai Saito
- Department of Chemistry
- Keio University
- Yokohama 223-8522
- Japan
| | - Tohru Yamada
- Department of Chemistry
- Keio University
- Yokohama 223-8522
- Japan
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12
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Ghosh P, Kwon NY, Han S, Kim S, Han SH, Mishra NK, Jung YH, Chung SJ, Kim IS. Site-Selective C-H Alkylation of Diazine N-Oxides Enabled by Phosphonium Ylides. Org Lett 2019; 21:6488-6493. [PMID: 31373494 DOI: 10.1021/acs.orglett.9b02365] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The synthesis of alkylated diazine derivatives is important for their practical utilization as pharmaceuticals and for other purposes. Herein, we describe the metal-free site-selective C-H alkylation of diazine N-oxides using phosphonium ylides that affords a variety of alkylated diazine derivatives with broad functional group tolerance. The utility of this method is showcased by the late-stage functionalization of a commercially available drug such as varenicline. Notably, the sequential C-H alkylation of pyrazine N-oxides for the total synthesis of a pyrazine-containing natural product, paenibacillin A, highlights the importance of this method.
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Affiliation(s)
- Prithwish Ghosh
- School of Pharmacy , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Na Yeon Kwon
- School of Pharmacy , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Sangil Han
- School of Pharmacy , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Saegun Kim
- School of Pharmacy , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Sang Hoon Han
- School of Pharmacy , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Neeraj Kumar Mishra
- School of Pharmacy , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Young Hoon Jung
- School of Pharmacy , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Sang J Chung
- School of Pharmacy , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - In Su Kim
- School of Pharmacy , Sungkyunkwan University , Suwon 16419 , Republic of Korea
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13
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Zhang Z, Stateman LM, Nagib DA. δ C-H (hetero)arylation via Cu-catalyzed radical relay. Chem Sci 2018; 10:1207-1211. [PMID: 30774920 PMCID: PMC6349054 DOI: 10.1039/c8sc04366c] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 11/09/2018] [Indexed: 12/23/2022] Open
Abstract
A radical relay strategy has been developed to enable selective δ C–H arylation. The approach employs a chiral copper catalyst, which serves the dual roles of generating an N-centered radical to promote intramolecular H-atom transfer, and then intercepting a distal C-centered radical for C–C bond formation with (hetero)aryl boronic acids.
A Cu-catalyzed strategy has been developed that harnesses a radical relay mechanism to intercept a distal C-centered radical for C–C bond formation. This approach enables selective δ C–H (hetero)arylation of sulfonamides via intramolecular hydrogen atom transfer (HAT) by an N-centered radical. The radical relay is both initiated and terminated by a Cu catalyst, which enables incorporation of arenes and heteroarenes by cross-coupling with boronic acids. The broad scope and utility of this catalytic method for δ C–H arylation is shown, along with mechanistic probes for selectivity of the HAT mechanism. A catalytic, asymmetric variant is also presented, as well as a method for accessing 1,1-diaryl-pyrrolidines via iterative δ C–H functionalizations.
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Affiliation(s)
- Zuxiao Zhang
- The Ohio State University , Department of Chemistry and Biochemistry , Columbus , OH 43210 , USA .
| | - Leah M Stateman
- The Ohio State University , Department of Chemistry and Biochemistry , Columbus , OH 43210 , USA .
| | - David A Nagib
- The Ohio State University , Department of Chemistry and Biochemistry , Columbus , OH 43210 , USA .
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