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La-Ongthong K, Chantarojsiri T, Soorukram D, Leowanawat P, Reutrakul V, Kuhakarn C. Electro-oxidative Methylation of 2-Isocyanobiaryls Using N,N-dimethylformamide (DMF) as Carbon Source: Synthesis of 6-Methylphenanthridines. Chem Asian J 2024; 19:e202400176. [PMID: 38489229 DOI: 10.1002/asia.202400176] [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: 02/19/2024] [Revised: 03/14/2024] [Accepted: 03/14/2024] [Indexed: 03/17/2024]
Abstract
A benign electrochemical method to access 6-methylphenanthridines from 2-isocyanobiaryls using N,N-dimethylformamide (DMF) as a methyl source is reported. The protocol operates at ambient temperature without the need for harmful methylating reagents. Mechanistic studies suggested that DMF delivered a methylene synthon, followed by reduction at the cathode and tautomerization. The method offers environmental benefits by avoiding metal-based reagents and harsh conditions.
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Affiliation(s)
- Kannika La-Ongthong
- Department of Chemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
- Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
| | - Teera Chantarojsiri
- Department of Chemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
- Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
| | - Darunee Soorukram
- Department of Chemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
- Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
| | - Pawaret Leowanawat
- Department of Chemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
- Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
| | - Vichai Reutrakul
- Department of Chemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
- Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
| | - Chutima Kuhakarn
- Department of Chemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
- Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
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Gharpure SJ, Chavan RS, Narang SR. Iron-Mediated Hydrogen Atom Transfer Radical Cyclization of Alkenyl Indoles and Pyrroles Gives Their Fused Derivatives: Total Synthesis of Bruceolline E and H. Org Lett 2024. [PMID: 38341858 DOI: 10.1021/acs.orglett.4c00032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2024]
Abstract
The iron-mediated hydrogen atom transfer (HAT) reaction is efficaciously employed for the synthesis of dihydropyrroloindoles and dihydropyrrolizines via 5-exo-trig radical cyclization where indoles and pyrroles are used as an acceptor. This radical approach has also been extended for the synthesis of tetrahydrocyclopenta[b]indolones via the Baldwin-disfavored 5-endo-trig cyclization pathway. The formal synthesis of bruceolline J and the total synthesis of bruceollines E and H have been expeditiously carried out by employing the former strategy.
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Affiliation(s)
- Santosh J Gharpure
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Rupali S Chavan
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Simran R Narang
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Wu X, Chen P, Gan M, Ji X, Deng GJ, Huang H. Redox-Neutral Cyclization of 2-Isocyanobiaryls through Photoredox/PPh 3 Dual Catalysis. Org Lett 2023; 25:9186-9190. [PMID: 38100717 DOI: 10.1021/acs.orglett.3c03744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
The photoredox/PPh3-mediated cyclization of 2-isocyanobiaryls has been developed. A substantial range of functional-group-rich phenanthridine derivatives were synthesized at room temperature in a highly selective and atom-economic manner. Mechanistic studies suggested that the cyclization process is probably mediated both by Ph3P radical cation with key 1,2-hydride transfer and hydrogen atom generated through O-H bond homolytic cleavage of Ph3P-OH radical intermediate.
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Affiliation(s)
- Xiaoting Wu
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Pu Chen
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Mengran Gan
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Xiaochen Ji
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Guo-Jun Deng
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, China
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Huawen Huang
- Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, China
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Zhou N, Wang L, Zhao F, Gao X, Zhao X, Zhang M. NHC-Catalyzed Tandem Reaction: A Strategy for the Synthesis of 2-Pyrrolidinone-Functionalized Phenanthridines. J Org Chem 2023; 88:16556-16565. [PMID: 37971950 DOI: 10.1021/acs.joc.3c02086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Herein, an N-heterocyclic carbene (NHC)-catalyzed tandem cyclization/addition/cyclization reaction of 2-isocyanobiaryls and α-bromo-N-cinnamylamides for the synthesis of 2-pyrrolidinone-functionalized phenanthridines is developed. This protocol features a radical cascade process, broad substrate scope, and good functional group compatibility under metal- and oxidant-free reaction conditions.
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Affiliation(s)
- Nengneng Zhou
- Key Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecule-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Lei Wang
- Key Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecule-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Fangli Zhao
- Key Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecule-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Xiang Gao
- Key Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecule-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Xiaowei Zhao
- Key Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecule-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Man Zhang
- Key Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecule-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241000, China
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