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Wang X, Yan H, Jia C, Fang Z, Duan J, Guo K. Synthesis of 2,4,6-Trisubstituted Pyrimidines through Copper-Catalyzed [4 + 2] Annulation of α,β-Unsaturated Ketoximes with Activated Nitriles. J Org Chem 2023; 88:12236-12243. [PMID: 37610229 DOI: 10.1021/acs.joc.3c00687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The copper-catalyzed [4 + 2] annulation of α,β-unsaturated ketoximes with activated nitriles for the rapid construction of 2,4,6-trisubstituted pyrimidines in moderate to good yields has been developed. The reaction features synthetic simplicity, good functional group tolerance, and gram-scale applicability. A plausible mechanism is proposed based on mechanistic investigations.
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Affiliation(s)
- Xuemei Wang
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Huan Yan
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Chenglong Jia
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Zheng Fang
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Jindian Duan
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Kai Guo
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
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Lu MZ, Goh J, Maraswami M, Jia Z, Tian JS, Loh TP. Recent Advances in Alkenyl sp 2 C-H and C-F Bond Functionalizations: Scope, Mechanism, and Applications. Chem Rev 2022; 122:17479-17646. [PMID: 36240299 DOI: 10.1021/acs.chemrev.2c00032] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Alkenes and their derivatives are featured widely in a variety of natural products, pharmaceuticals, and advanced materials. Significant efforts have been made toward the development of new and practical methods to access this important class of compounds by selectively activating the alkenyl C(sp2)-H bonds in recent years. In this comprehensive review, we describe the state-of-the-art strategies for the direct functionalization of alkenyl sp2 C-H and C-F bonds until June 2022. Moreover, metal-free, photoredox, and electrochemical strategies are also covered. For clarity, this review has been divided into two parts; the first part focuses on currently available alkenyl sp2 C-H functionalization methods using different alkene derivatives as the starting materials, and the second part describes the alkenyl sp2 C-F bond functionalization using easily accessible gem-difluoroalkenes as the starting material. This review includes the scope, limitations, mechanistic studies, stereoselective control (using directing groups as well as metal-migration strategies), and their applications to complex molecule synthesis where appropriate. Overall, this comprehensive review aims to document the considerable advancements, current status, and emerging work by critically summarizing the contributions of researchers working in this fascinating area and is expected to stimulate novel, innovative, and broadly applicable strategies for alkenyl sp2 C-H and C-F bond functionalizations in the coming years.
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Affiliation(s)
- Ming-Zhu Lu
- College of Advanced Interdisciplinary Science and Technology, Henan University of Technology, Zhengzhou 450001, China.,School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637371, Singapore
| | - Jeffrey Goh
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637371, Singapore
| | - Manikantha Maraswami
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637371, Singapore
| | - Zhenhua Jia
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Jie-Sheng Tian
- School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, China
| | - Teck-Peng Loh
- College of Advanced Interdisciplinary Science and Technology, Henan University of Technology, Zhengzhou 450001, China.,School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637371, Singapore.,Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China
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Tanaka K, Hashimoto Y, Morita N, Tamura O. Directing-Group-Free Palladium-Catalyzed C–H Arylation of Aldoxime Using Oxime’s Umpolung Properties. Org Lett 2022; 24:8954-8958. [DOI: 10.1021/acs.orglett.2c03387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Kosaku Tanaka
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
| | - Yoshimitsu Hashimoto
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
| | - Nobuyoshi Morita
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
| | - Osamu Tamura
- Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
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Yamada T, Hashimoto Y, Tanaka K, Morita N, Tamura O. Cationic palladium(ii)-catalyzed synthesis of substituted pyridines from α,β-unsaturated oxime ethers. RSC Adv 2022; 12:21548-21557. [PMID: 36043185 PMCID: PMC9351437 DOI: 10.1039/d2ra03875g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 07/14/2022] [Indexed: 11/21/2022] Open
Abstract
An efficient method for the synthesis of multi-substituted pyridines from β-aryl-substituted α,β-unsaturated oxime ethers and alkenes via Pd-catalyzed C–H activation has been developed. The method, using Pd(OAc)2 and a sterically hindered pyridine ligand, provides access to various multi-substituted pyridines with complete regioselectivity. Mechanistic studies suggest that the pyridine products are formed by Pd-catalyzed electrophilic C–H alkenylation of α,β-unsaturated oxime followed by aza-6π-electrocyclization. The utility of this method is showcased by the synthesis of 4-aryl-substituted pyridine derivatives, which are difficult to synthesize efficiently using previously reported Rh-catalyzed strategies with alkenes. An efficient method for the synthesis of multi-substituted pyridines from α,β-unsaturated oxime ethers via cationic Pd(ii)-catalyzed C–H activation has been developed.![]()
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Affiliation(s)
- Takahiro Yamada
- Showa Pharmaceutical University Machida Tokyo 194-8543 Japan
| | | | - Kosaku Tanaka
- Showa Pharmaceutical University Machida Tokyo 194-8543 Japan
| | | | - Osamu Tamura
- Showa Pharmaceutical University Machida Tokyo 194-8543 Japan
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Fernandes R, Mhaske K, Balhara R, Jindal G, Narayan R. Copper-Catalyzed Aerobic Cross-Dehydrogenative Coupling of β-Oxime Ether Furan with Indole. Chem Asian J 2022; 17:e202101369. [PMID: 35146932 DOI: 10.1002/asia.202101369] [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: 12/09/2021] [Revised: 01/30/2022] [Indexed: 11/09/2022]
Abstract
Heterobiaryls serve as relevant structural motifs in many fields of high applicative importance such as drugs, agrochemicals, organic functional materials etc. Cross-dehydrogenative coupling involving direct oxidation of two C-H bonds to construct a C-C bond is actively being pursued as a more benign and 'greener' alternative for synthesizing heterobiaryls. Herein, we report a Cu(I)-catalyzed cross-dehydrogenative coupling of indoles and furans, two of the most important aromatic heterocycles using air as the terminal oxidant. The reaction proceeds with regio- and chemoselectivity to give the cross-coupled products in good to excellent yields generally. A broad substrate scope with respect to both the coupling partners has been demonstrated to prove the generality of this reaction. This represents the hitherto unexplored cross-dehydrogenative coupling methodology to obtain an indole-furan biaryl motif.
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Affiliation(s)
- Rushil Fernandes
- School of Chemical and Materials Sciences (SCMS), Indian Institute of Technology (IIT) Goa GEC Campus, Farmagudi, Ponda, Goa-403401, India
| | - Krishna Mhaske
- School of Chemical and Materials Sciences (SCMS), Indian Institute of Technology (IIT) Goa GEC Campus, Farmagudi, Ponda, Goa-403401, India
| | - Reena Balhara
- Department of Organic Chemistry, Indian Institute of Science, Bangalore-560012, Karnataka, India
| | - Garima Jindal
- Department of Organic Chemistry, Indian Institute of Science, Bangalore-560012, Karnataka, India
| | - Rishikesh Narayan
- School of Chemical and Materials Sciences (SCMS), Indian Institute of Technology (IIT) Goa GEC Campus, Farmagudi, Ponda, Goa-403401, India
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Furugoori M, Yoshida K, Hashimoto Y, Morita N, Tanaka Iii K, Tamura O. Electrophilic Epoxidation of α,β-Unsaturated Oximes with Dioxiranes and Ring Opening of the Epoxides. Chem Pharm Bull (Tokyo) 2021; 69:1010-1016. [PMID: 34305073 DOI: 10.1248/cpb.c21-00533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
α,β-Unsaturated oximes underwent electrophilic epoxidation with in-situ-generated dimethyldioxirane to give the corresponding epoxides in good yields. This reaction is an example of "carbonyl umpolung" by transformation of α,β-unsaturated ketones to their oximes. Nucleophilic ring-opening reactions of the epoxides afforded α-substituted products. Shi asymmetric epoxidation of the oximes proceeded with moderate enantioselectivity.
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Rong B, Xu G, Yan H, Zhang S, Wu Q, Zhu N, Duan J, Guo K. The copper-catalyzed synthesis of dihydrooxazoles from α,β-unsaturated ketoximes and activated ketones. Chem Commun (Camb) 2021; 57:7272-7275. [PMID: 34195708 DOI: 10.1039/d1cc02422a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The first copper-catalyzed [3+2]-type condensation reaction of α,β-unsaturated ketoximes with activated ketones has been described for the synthesis of dihydrooxazoles, especially trifluoromethyl-decorated dihydrooxazoles. Notable features of this method include its broad substrate scope, good functional group tolerance, and simple operation.
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Affiliation(s)
- Binsen Rong
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, 30 Puzhu Rd S, Nanjing, 211816, China.
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Yamada T, Hashimoto Y, Tanaka K, Morita N, Tamura O. Palladium(II)-Catalyzed Substituted Pyridine Synthesis from α,β-Unsaturated Oxime Ethers via a C-H Alkenylation/Aza-6π-Electrocyclization Approach. Org Lett 2021; 23:1659-1663. [PMID: 33567210 DOI: 10.1021/acs.orglett.1c00061] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
An efficient synthetic method for multisubstituted pyridines from β-aryl-substituted α,β-unsaturated oxime ethers and alkenes via Pd-catalyzed C-H activation has been developed. Systematic optimization of catalyst ligands revealed that sterically hindered pyridines increased the reactivity. Mechanistic studies suggested that the products are formed by Pd-catalyzed β-alkenylation of α,β-unsaturated oxime followed by aza-6π-electrocyclization. Various oximes and alkenes could be utilized to afford multisubstituted pyridines with complete regioselectivity. The usefulness of this methodology was showcased by the synthesis of 4-aryl-substituted pyridine derivatives, which are difficult to access with previously reported Rh-catalyzed approaches with alkenes.
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Affiliation(s)
- Takahiro Yamada
- Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | | | - Kosaku Tanaka
- Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | | | - Osamu Tamura
- Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
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