1
|
Zhou F, Jin H, Zhang Y, Li J, Walsh PJ, Lin S. Base-Promoted Tandem Synthesis of 2-Substituted Indoles and N-Fused Polycyclic Indoles. Org Lett 2023; 25:7132-7136. [PMID: 37751201 DOI: 10.1021/acs.orglett.3c02609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Herein is developed a base-promoted approach for the synthesis of C2-substituted indoles and N-fused polycyclic indoles via 5-endo-dig cyclization of 2-alkynyl anilines, followed by a 1,3'-acyl migration or a dearomatizing Michael addition process. A range of N-H free indoles and 8,9-dihydropyrido[1,2-a]indol-6(7H)-one scaffolds were synthesized in good to excellent yields with broad scope.
Collapse
Affiliation(s)
- Fan Zhou
- School of Medicine, Hangzhou City University, Hangzhou 310015, People's Republic of China
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Huimin Jin
- School of Medicine, Hangzhou City University, Hangzhou 310015, People's Republic of China
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Yuanhang Zhang
- School of Medicine, Hangzhou City University, Hangzhou 310015, People's Republic of China
| | - Jie Li
- School of Medicine, Hangzhou City University, Hangzhou 310015, People's Republic of China
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Patrick J Walsh
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Shengzhang Lin
- School of Medicine, Hangzhou City University, Hangzhou 310015, People's Republic of China
| |
Collapse
|
2
|
Mandal M, Pradhan R, Lourderaj U, Balamurugan R. Dodging the Conventional Reactivity of o-Alkynylanilines under Gold Catalysis for Distal 7- endo- dig Cyclization. J Org Chem 2023; 88:2260-2287. [PMID: 36744758 DOI: 10.1021/acs.joc.2c02668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A direct ring-closing strategy involving a less facile 7-endo-dig carbacyclization of o-alkynylaniline derivatives for the synthesis of benzo[b]azepines has been presented. The trivial well-documented 5-endo-dig cyclization in o-alkynylaniline derivatives due to high nucleophilicity of nitrogen has been overcome by using their vinylogous amides under gold catalysis to access a wide array of benzo[b]azepines in an atom economical way with excellent functional group compatibility. Deuterium scrambling experiments and DFT studies favor a mechanism involving stabilizing conformational change of the initially formed seven-membered vinyl gold intermediate through a key cyclopropyl gold carbene intermediate and its subsequent protodeauration mediated by the counter anion.
Collapse
Affiliation(s)
- Mou Mandal
- School of Chemistry, University of Hyderabad, Hyderabad, Telangana-500046, India
| | - Renuka Pradhan
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) Bhubaneswar, HBNI, P.O. Jatni, Khurda, Odisha-752050, India
| | - Upakarasamy Lourderaj
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) Bhubaneswar, HBNI, P.O. Jatni, Khurda, Odisha-752050, India
| | | |
Collapse
|
3
|
Shit S, Bora SK, Sahu AK, Saikia AK. Synthesis of Spiro[furan-2,1'-isoindolin]-3'-ones from 2-(4-Hydroxybut-1-yn-1-yl)benzonitriles and Aryl Aldehydes under the Action of Triflic Acid. J Org Chem 2022; 87:11634-11643. [PMID: 35976061 DOI: 10.1021/acs.joc.2c01286] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The synthesis of spiro[furan-2,1'-isoindolin]-3'-ones from 2-(4-hydroxybut-1-yn-1-yl)benzonitriles and aryl aldehydes is demonstrated. It involves the initial formation of dihydrofuranylideneisoindolinone via intramolecular sequential Prins and Ritter reactions, followed by the ring opening of the furanyl moiety to generate N-acyliminium ions and alcohols for the final cyclization reaction, and the spiro-cyclic compounds are produced in moderate to good yields. It is a one-pot, three-component reaction in which one new quaternary carbon, two five-membered rings, one C-N bond, two C-O bonds, and one C-C bond are formed. The reaction is carried out with a Brønsted acid from 0 °C to room temperature within a short period of time.
Collapse
Affiliation(s)
- Sudip Shit
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Surjya Kumar Bora
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Archana Kumari Sahu
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Anil K Saikia
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| |
Collapse
|
4
|
Chaisan N, Ruengsangtongkul S, Tummatorn J, Ruchirawat S, Chainok K, Thongsornkleeb C. Dibrominative Spirocyclization of 2-Butynolyl Anilides: Synthesis of gem-Dibromospirocyclic Benzo[ d][1,3]oxazines and Their Application in the Synthesis of 4 H-Furo[3,2- b]indoles. J Org Chem 2021; 86:4671-4698. [PMID: 33689323 DOI: 10.1021/acs.joc.1c00086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The combination of catalytic aqueous hydrochloric acid (HCl) and N-bromosuccinimide (NBS) generated electrophilic bromine monochloride (BrCl), which readily induced spiroannulation of 2-alkynolyl anilides (n = 1-3) to form gem-dibromospirocyclic benzo[d][1,3]oxazines in up to 92% yield. The reaction occurred under mild and metal-free conditions using EtOAc as a green solvent. The resulted spirocyclic products contained benzo[d][1,3]oxazine, which was useful both as a pharmacophore and synthetic precursor. In addition, the current protocol allowed to effortlessly introduce the sp3-gem-dibromide carbon adjacent to the sterically demanding spiroketal center. These spiroheterocycles (n = 1) were shown to be synthetically versatile and conveniently maneuvered. Base-promoted debrominative aromatization of these spirocycles unmasked rare and synthetically useful 2-aryl-3-bromofurans in mostly excellent yields. These 3-bromofurans were well-suited substrates for intramolecular Ullmann C-N bond coupling to construct difficult-to-prepare 4H-furo[3,2-b]indoles. Additionally, the current protocol was flexible and adaptable to preparing the gem-dichloride variants.
Collapse
Affiliation(s)
- Nattawadee Chaisan
- Program on Chemical Biology, Chulabhorn Graduate Institute, Center of Excellence on Environmental Health and Toxicology (EHT), Ministry of Education, 54 Kamphaeng Phet 6, Laksi, Bangkok 10210, Thailand
| | - Sureeporn Ruengsangtongkul
- Laboratory of Medicinal Chemistry, Chulabhorn Research Institute, 54 Kamphaeng Phet 6, Laksi, Bangkok 10210, Thailand
| | - Jumreang Tummatorn
- Laboratory of Medicinal Chemistry, Chulabhorn Research Institute, 54 Kamphaeng Phet 6, Laksi, Bangkok 10210, Thailand.,Program on Chemical Biology, Chulabhorn Graduate Institute, Center of Excellence on Environmental Health and Toxicology (EHT), Ministry of Education, 54 Kamphaeng Phet 6, Laksi, Bangkok 10210, Thailand
| | - Somsak Ruchirawat
- Laboratory of Medicinal Chemistry, Chulabhorn Research Institute, 54 Kamphaeng Phet 6, Laksi, Bangkok 10210, Thailand.,Program on Chemical Biology, Chulabhorn Graduate Institute, Center of Excellence on Environmental Health and Toxicology (EHT), Ministry of Education, 54 Kamphaeng Phet 6, Laksi, Bangkok 10210, Thailand
| | - Kittipong Chainok
- Thammasat University Research Unit in Multifunctional Crystalline Materials and Applications (TU-MCMA), Faculty of Science and Technology, Thammasat University, Pathum Thani 12121, Thailand
| | - Charnsak Thongsornkleeb
- Laboratory of Organic Synthesis, Chulabhorn Research Institute, 54 Kamphaeng Phet 6, Laksi, Bangkok 10210, Thailand.,Program on Chemical Biology, Chulabhorn Graduate Institute, Center of Excellence on Environmental Health and Toxicology (EHT), Ministry of Education, 54 Kamphaeng Phet 6, Laksi, Bangkok 10210, Thailand
| |
Collapse
|
5
|
Cai T, Feng C, Shen F, Bian K, Wu C, Shen R, Gao Y. Synthesis of 2‐Substituted Benzothio(seleno)phenes and Indoles
via
Ag‐Catalyzed Cyclization/Demethylation of 2‐Alkynylthio(seleno)anisoles and 2‐Alkynyldimethylanilines. European J Org Chem 2020. [DOI: 10.1002/ejoc.202001465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Tao Cai
- Department College of Chemistry and Chemical Engineering Shaoxing University Shaoxing 312000 P. R. China
| | - Chengjie Feng
- Department College of Chemistry and Chemical Engineering Shaoxing University Shaoxing 312000 P. R. China
| | - Fangqi Shen
- Department College of Chemistry and Chemical Engineering Shaoxing University Shaoxing 312000 P. R. China
| | - Kejun Bian
- Department College of Chemistry and Chemical Engineering Shaoxing University Shaoxing 312000 P. R. China
| | - Chunlei Wu
- Department College of Chemistry and Chemical Engineering Shaoxing University Shaoxing 312000 P. R. China
| | - Runpu Shen
- Department College of Chemistry and Chemical Engineering Shaoxing University Shaoxing 312000 P. R. China
| | - Yuzhen Gao
- Key Laboratory of Coal to Ethylene Glycol and Its Related Technology Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences Fuzhou 350002 P. R. China
| |
Collapse
|