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Williams M, Boyer A. Modular Synthesis of Highly Substituted 3-Azapyrroles by Rh(II)-Catalyzed N-H Bond Insertion and Cyclodehydration. J Org Chem 2022; 87:16139-16156. [PMID: 35503987 PMCID: PMC9764362 DOI: 10.1021/acs.joc.2c00434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A modular synthesis of highly substituted 3-azapyrroles has been developed using a three-step sequence comprising copper-catalyzed alkyne-azide cycloaddition (CuAAC), N-H bond insertion, and cyclodehydration. 1-Sulfonyl-1,2,3-triazoles (1-STs) can be accessed from common alkyne and sulfonyl azide building blocks by CuAAC using CuTC. Rhodium(II)-acetate-promoted 1-ST denitrogenation results in highly electrophilic rhodium azavinyl carbenes that, here, underwent insertion into the N-H bond of secondary α-aminoketones to form 1,2-aminoalkenes. These products were cyclized and dehydrated using BF3·OEt2 into highly substituted 3-azapyrroles. The three steps (CuAAC, N-H bond insertion, and cyclodehydration) could be telescoped into a one-pot process. The method proved to be highly efficient and tolerated a wide range of substituents.
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Yescas-Galicia D, Restrepo-Osorio RA, García-González AN, Hernández-Benítez RI, Espinoza-Hicks JC, Escalante CH, Barrera E, Santoyo BM, Delgado F, Tamariz J. Divergent Pd-catalyzed Functionalization of 4-Oxazolin-2-ones and 4-Methylene-2-oxazolidinones and Synthesis of Heterocyclic-Fused Indoles. J Org Chem 2022; 87:13034-13052. [PMID: 36153994 DOI: 10.1021/acs.joc.2c01563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Palladium-catalyzed functionalization was presently performed on two building blocks: 4-oxazolin-2-ones and 4-methylene-2-oxazolidinones. Direct Heck arylation of 4-oxazolin-2-ones led to a series of 5-aryl-4-oxazolin-2-ones, including analogues with N-chiral auxiliary, in an almost quantitative yield. The Pd(II)-catalyzed homocoupling reaction of 4-oxazolin-2-ones provided novel heterocyclic across-ring dienes. Meanwhile, the intramolecular cross-coupling of N-aryl-4-methylene-2-oxazolidinones furnished a series of oxazolo[3,4-a]indol-3-ones. Further functionalization of 4-methylene-2-oxazolidinones afforded substituted indoles and heterocyclic-fused indoles with aryl, bromo, carbinol, formyl, and vinyl groups. A computational study was carried out to account for the behavior of the formylated derivatives. The currently developed methodology was applied to a new formal total synthesis of ellipticine.
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Affiliation(s)
- Daniel Yescas-Galicia
- Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, 11340 Mexico City, Mexico
| | - Rodrigo A Restrepo-Osorio
- Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, 11340 Mexico City, Mexico
| | - Ailyn N García-González
- Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, 11340 Mexico City, Mexico
| | - Roberto I Hernández-Benítez
- Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, 11340 Mexico City, Mexico
| | - José C Espinoza-Hicks
- Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Autónoma de Chihuahua, Circuito Universitario S/N, 31000 Chihuahua, Chih., Mexico
| | - Carlos H Escalante
- Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, 11340 Mexico City, Mexico
| | - Edson Barrera
- Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, 11340 Mexico City, Mexico
| | - Blanca M Santoyo
- Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, 11340 Mexico City, Mexico
| | - Francisco Delgado
- Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, 11340 Mexico City, Mexico
| | - Joaquín Tamariz
- Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, 11340 Mexico City, Mexico
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Song Y, Zhang H, Guo J, Shao Y, Ding Y, Zhu L, Yao X. Visible‐Light‐Induced Oxidative α‐Alkylation of Glycine Derivatives with Ethers under Metal‐Free Conditions. European J Org Chem 2021. [DOI: 10.1002/ejoc.202101242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Yang Song
- Department of Applied Chemistry College of Material Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 PR China
| | - Hao Zhang
- Department of Applied Chemistry College of Material Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 PR China
| | - Jiabao Guo
- Department of Applied Chemistry College of Material Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 PR China
| | - Yifei Shao
- Department of Applied Chemistry College of Material Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 PR China
| | - Yuzhou Ding
- Department of Chemistry School of Pharmacy Nanjing Medical University Nanjing 211166 PR China
| | - Li Zhu
- Department of Chemistry School of Pharmacy Nanjing Medical University Nanjing 211166 PR China
| | - Xiaoquan Yao
- Department of Applied Chemistry College of Material Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 PR China
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Regioselective Mercury(I)/Palladium(II)-Catalyzed Single-Step Approach for the Synthesis of Imines and 2-Substituted Indoles. Molecules 2021; 26:molecules26134092. [PMID: 34279432 PMCID: PMC8271454 DOI: 10.3390/molecules26134092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/22/2021] [Accepted: 06/29/2021] [Indexed: 12/21/2022] Open
Abstract
An efficient synthesis of ketimines was achieved through a regioselective Hg(I)-catalyzed hydroamination of terminal acetylenes in the presence of anilines. The Pd(II)-catalyzed cyclization of these imines into the 2-substituted indoles was satisfactorily carried out by a C-H activation. In a single-step approach, a variety of 2-substituted indoles were also generated via a Hg(I)/Pd(II)-catalyzed, one-pot, two-step process, starting from anilines and terminal acetylenes. The arylacetylenes proved to be more effective than the alkyl derivatives.
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Cheng D, Shen Y, Wu Z, Xu X, Yan J. Metal-Free Tandem Oxidative Cyclization for the Synthesis of 1,2-Dihydropyridazines and Pyrazoles. J Org Chem 2021; 86:8563-8575. [PMID: 34133155 DOI: 10.1021/acs.joc.1c00020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mediated by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), a novel oxidative coupling of hydrazones and 1,3-diarylpropenes has been disclosed to generate appealing β,γ-unsaturated hydrazones, which further undergo 5-exo-trig or 6-endo-trig cascade cyclization to give the respective 1,2-dihydropyridazines or pyrazoles selectively under metal-free conditions. The mechanisms of the coupling and subsequent cyclization are proposed.
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Affiliation(s)
- Dongping Cheng
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, P. R. China
| | - Yinqiang Shen
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, P. R. China
| | - Ziliang Wu
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, P. R. China
| | - Xiaoliang Xu
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, P. R. China
| | - Jizhong Yan
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, P. R. China
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