1
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Liu S, Liu Q, Cheng L, Liu L. Construction of 2-Substituted-3-aryl Benzofurans and Indoles through an Acid-Catalyzed Cascade Intramolecular Friedel-Crafts Reaction/Rearrangement/Aromatization Process. J Org Chem 2024. [PMID: 39066704 DOI: 10.1021/acs.joc.4c01494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
We present here a new method for the synthesis of 2-substituted-3-aryl benzoheterocycles through a more challenging constrained [1,5]-type Friedel-Crafts reaction/rearrangement and aromatization process. By using the readily available 2-aryoxy-1,3-indandiones and 2-arylamino-1,3-indandiones, a range of 2-substituted-3-aryl benzofurans and indoles were prepared in good to excellent yields (yields up to 86%) under the catalysis of CF3SO3H or Sm(OTf)3. Compared with previous methods for constructing similar structures, this approach offers several advantages, including the use of easily accessible starting materials, mild reaction conditions, high yield, excellent regio- and diastereoselectivity, and a broad substrate scope.
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Affiliation(s)
- Shaodong Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qi Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liang Cheng
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Li Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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2
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Saini G, Kapur M. Palladium-catalyzed functionalizations of acidic and non-acidic C(sp 3)-H bonds - recent advances. Chem Commun (Camb) 2021; 57:1693-1714. [PMID: 33492315 DOI: 10.1039/d0cc06892f] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A tremendous upsurge has been seen in the recent decade for the proximal and remote functionalization of activated and unactivated substrates via palladium redox pathways. This feature article discusses some of the recent reports on direct as well as indirect C(sp3)-H functionalization via cross-coupling reactions under palladium catalysis. Activated substrates (possessing acidic C(sp3)-H) including enones, ketones, aldehydes, silylenol ethers, esters, silyl ketene acetals, amides, cyano, α-amino esters, and O-carbamates, capable of undergoing cross-coupling reactions at the α-, β-, γ-, δ- and ε-positions, will be discussed. To overcome the challenging task of achieving regioselectivity, a variety of innovative modifications have been reported. The reports of C-H activations based on directing group, and as native functionality have been illustrated at the β-, γ- and δ-positions. Substrates such as α-amino esters, carbonyls, carboxylic acids and their derivatives, afford site-selective C(sp3)-H functionalization via varied-sized reactive metallacycles and are a unique class of substrates whose C(sp3)-H functionalizations were earlier considered as very difficult.
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Affiliation(s)
- Gaurav Saini
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, MP, India.
| | - Manmohan Kapur
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, MP, India.
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3
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Ban K, Yamamoto Y, Sajiki H, Sawama Y. Arylation of indoles using cyclohexanones dually-catalyzed by niobic acid and palladium-on-carbons. Org Biomol Chem 2020; 18:3898-3902. [PMID: 32400844 DOI: 10.1039/d0ob00702a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
3-Arylindoles were easily constructed from indoles and cyclohexanone derivatives using a combination of catalytic niobic acid-on-carbon (Nb2O5/C) and palladium-on-carbon (Pd/C) under heating conditions without any oxidants. The Lewis acidic Nb2O5/C promoted the nucleophilic addition of indoles to the cyclohexanones, and the subsequent dehydration and Pd/C-catalyzed dehydrogenation produced the 3-arylindoles. The additive 2,3-dimethyl-1,3-butadiene worked as a hydrogen acceptor to facilitate the dehydrogenation step.
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Affiliation(s)
- Kazuho Ban
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University, 1-25-4 Daigakunishi, Gifu 501-1196, Japan.
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4
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Ekebergh A, Begon R, Kann N. Ruthenium-Catalyzed E-Selective Alkyne Semihydrogenation with Alcohols as Hydrogen Donors. J Org Chem 2020; 85:2966-2975. [PMID: 32027128 PMCID: PMC7343281 DOI: 10.1021/acs.joc.9b02721] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Selective
direct ruthenium-catalyzed semihydrogenation of diaryl
alkynes to the corresponding E-alkenes has been achieved
using alcohols as the hydrogen source. The method employs a simple
ruthenium catalyst, does not require external ligands, and affords
the desired products in > 99% NMR yield in most cases (up to 93%
isolated
yield). Best results were obtained using benzyl alcohol as the hydrogen
donor, although biorenewable alcohols such as furfuryl alcohol could
also be applied. In addition, tandem semihydrogenation–alkylation
reactions were demonstrated, with potential applications in the synthesis
of resveratrol derivatives.
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Affiliation(s)
- Andreas Ekebergh
- Chemistry and Biochemistry, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Romain Begon
- Chemistry and Biochemistry, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Nina Kann
- Chemistry and Biochemistry, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Göteborg, Sweden
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5
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Peng H, Jiang K, Zhen G, Wang F, Yin B. Access to N-unprotected 2-amide-substituted indoles from Ugi adducts via palladium-catalyzed intramolecular cyclization of o-iodoanilines bearing furan rings. RSC Adv 2020; 10:11750-11754. [PMID: 35496608 PMCID: PMC9050509 DOI: 10.1039/d0ra01830a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 02/28/2020] [Indexed: 11/21/2022] Open
Abstract
A variety of N-unprotected 2-amide-substituted indoles were synthesized from readily available furfural-based Ugi adducts in moderate to good yields via palladium-catalyzed intramolecular cyclization of o-iodoanilines bearing furan rings. These reactions involved a cascade sequence consisting of dearomatizing arylation, opening of the furan ring, and deprotection of the N atom. A variety of N-unprotected 2-amide-substituted indoles were synthesized from readily available furfural-based Ugi adducts in moderate to good yields via palladium-catalyzed intramolecular cyclization of o-iodoanilines bearing furan rings.![]()
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Affiliation(s)
- Hui Peng
- Key Laboratory of Functional Molecular Engineering of Guangdong Province
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou
- P. R. China
| | - Kai Jiang
- Key Laboratory of Functional Molecular Engineering of Guangdong Province
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou
- P. R. China
| | - Guangjin Zhen
- Key Laboratory of Functional Molecular Engineering of Guangdong Province
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou
- P. R. China
| | - Furong Wang
- Key Laboratory of Functional Molecular Engineering of Guangdong Province
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou
- P. R. China
| | - Biaolin Yin
- Key Laboratory of Functional Molecular Engineering of Guangdong Province
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou
- P. R. China
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6
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Saini G, Mondal A, Kapur M. Palladium-Mediated Remote Functionalization in γ- and ε-Arylations and Alkenylations of Unblocked Cyclic Enones. Org Lett 2019; 21:9071-9075. [PMID: 31680525 DOI: 10.1021/acs.orglett.9b03462] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We report herein an extensive investigation of simple and regioselective endo- as well as exo-γ-arylations of silyl-dienol ethers of unblocked cyclic enones with the utilization of palladium-catalyzed, modified Kuwajima-Urabe conditions. We have also successfully explored a new exo-ε-arylation of silyl-trienol ethers of π-extended cyclic enones. In addition, we also report, herein, exclusive γ- and ε-alkenylation of silyl-dienol and silyl-trienol ethers of cyclic enones.
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Affiliation(s)
- Gaurav Saini
- Department of Chemistry , Indian Institute of Science Education and Research Bhopal , Bhopal Bypass Road , Bhauri, Bhopal 462066 , MP , India
| | - Arpan Mondal
- Department of Chemistry , Indian Institute of Science Education and Research Bhopal , Bhopal Bypass Road , Bhauri, Bhopal 462066 , MP , India
| | - Manmohan Kapur
- Department of Chemistry , Indian Institute of Science Education and Research Bhopal , Bhopal Bypass Road , Bhauri, Bhopal 462066 , MP , India
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7
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Kumar GS, Singh D, Kumar M, Kapur M. Palladium-Catalyzed Aerobic Oxidative Coupling of Allylic Alcohols with Anilines in the Synthesis of Nitrogen Heterocycles. J Org Chem 2018. [DOI: 10.1021/acs.joc.8b00287] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Gangam Srikanth Kumar
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, MP, India
| | - Diksha Singh
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, MP, India
| | - Manish Kumar
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, MP, India
| | - Manmohan Kapur
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, MP, India
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8
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Saxena P, Kapur M. Cobalt-Catalyzed C−H Nitration of Indoles by Employing a Removable Directing Group. Chem Asian J 2018; 13:861-870. [DOI: 10.1002/asia.201800036] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 02/07/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Paridhi Saxena
- Department of Chemistry; Indian Institute of Science Education and Research Bhopal, Academic Building II; Bhopal Bypass Road Bhauri, Bhopal 462066 MP India
| | - Manmohan Kapur
- Department of Chemistry; Indian Institute of Science Education and Research Bhopal, Academic Building II; Bhopal Bypass Road Bhauri, Bhopal 462066 MP India
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9
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Saini G, Kumar P, Kumar GS, Mangadan ARK, Kapur M. Palladium-Catalyzed α-Arylation of Silylenol Ethers in the Synthesis of Isoquinolines and Phenanthridines. Org Lett 2018; 20:441-444. [DOI: 10.1021/acs.orglett.7b03776] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Gaurav Saini
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass
Road, Bhauri, Bhopal 462066, MP, India
| | - Pravin Kumar
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass
Road, Bhauri, Bhopal 462066, MP, India
| | - Gangam Srikanth Kumar
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass
Road, Bhauri, Bhopal 462066, MP, India
| | - Arun Raj Kizhakkayil Mangadan
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass
Road, Bhauri, Bhopal 462066, MP, India
| | - Manmohan Kapur
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass
Road, Bhauri, Bhopal 462066, MP, India
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10
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Gattu R, Bhattacharjee S, Mahato K, Khan AT. Electronic effect of substituents on anilines favors 1,4-addition totrans-β-nitrostyrenes: access toN-substituted 3-arylindoles and 3-arylindoles. Org Biomol Chem 2018; 16:3760-3770. [DOI: 10.1039/c8ob00736e] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A simple and an efficient method for the regioselective synthesis ofN-alkyl/aryl/H 3-arylindole derivatives fromN-substituted anilines andtrans-β-nitrostyrenes has been described using 10 mol% of bismuth(iii) triflate as a catalyst in acetonitrile at 80 °C.
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Affiliation(s)
- Radhakrishna Gattu
- Department of Chemistry
- Indian Institute of Technology Guwahati
- Guwahati 781 039
- India
| | | | - Karuna Mahato
- Department of Chemistry
- Indian Institute of Technology Guwahati
- Guwahati 781 039
- India
| | - Abu T. Khan
- Department of Chemistry
- Indian Institute of Technology Guwahati
- Guwahati 781 039
- India
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11
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Panyam PKR, Gandhi T. Palladium(II)/N-Heterocyclic Carbene-Catalyzed Regioselective Heteroannulation of Tertiary Propargyl Alcohols ando-Haloanilines to form 2-Alkenylindoles. Adv Synth Catal 2017. [DOI: 10.1002/adsc.201601349] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | - Thirumanavelan Gandhi
- Department of Chemistry; School of Advanced Sciences; VIT University; Vellore - 632014 India
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12
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Mishra A, Deb I. Palladium-Catalyzed Oxidative Cyclization for the Synthesis of Indolyl/Pyrrolyl 3-Phosphonates. Adv Synth Catal 2016. [DOI: 10.1002/adsc.201600321] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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13
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Kumar GS, Kapur M. Ruthenium-Catalyzed, Site-Selective C–H Allylation of Indoles with Allyl Alcohols as Coupling Partners. Org Lett 2016; 18:1112-5. [DOI: 10.1021/acs.orglett.6b00217] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gangam Srikanth Kumar
- Department
of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass
Road, Bhauri, Bhopal 462066, India
| | - Manmohan Kapur
- Department
of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass
Road, Bhauri, Bhopal 462066, India
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