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Sekar P, Gupta A, English LE, Rabbitt CE, Male L, Jupp AR, Davies PW. Regiodivergent Synthesis of 4- and 5-Sulfenyl Oxazoles from Alkynyl Thioethers. Chemistry 2024; 30:e202401465. [PMID: 38743746 DOI: 10.1002/chem.202401465] [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: 04/15/2024] [Revised: 05/11/2024] [Accepted: 05/13/2024] [Indexed: 05/16/2024]
Abstract
The regiodivergent synthesis of 4- and 5-sulfenyl oxazoles from 1,4,2-dioxazoles and alkynyl thioethers has been achieved. Gold-catalysed conditions are used to favour the formation of 5-sulfenyl oxazoles via β-selective attack of the nitrenoid relative to the sulfenyl group. In contrast, 4-sulfenyl oxazoles are formed by α-selective reaction under Brønsted acid conditions from the same substrates. The nature of stabilising gold-sulfur interactions have been investigated by natural bond orbital analysis, showing that the S→Au interactions are significantly stronger in the intermediate that favours the 5-sulfenyl oxazoles. A kinetic survey identifies catalyst inhibition processes. This study into the regiodivergent methods includes the development of telescoped annulation-oxidation protocols for regioselective access to oxazole sulfoxides and sulfones.
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Affiliation(s)
- Prakash Sekar
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Aniket Gupta
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Laura E English
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Clare E Rabbitt
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Louise Male
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Andrew R Jupp
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Paul W Davies
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
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Majeed A, Zafar A, Mushtaq Z, Iqbal MA. Advances in gold catalyzed synthesis of quinoid heteroaryls. RSC Adv 2024; 14:21047-21064. [PMID: 38962094 PMCID: PMC11220603 DOI: 10.1039/d4ra03368j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 06/27/2024] [Indexed: 07/05/2024] Open
Abstract
This review explores recent advancements in synthesizing quinoid heteroaryls, namely quinazoline and quinoline, vital in chemistry due to their prevalence in natural products and pharmaceuticals. It emphasizes the rapid, highly efficient, and economically viable synthesis achieved through gold-catalyzed cascade protocols. By investigating methodologies and reaction pathways, the review underscores exceptional yields attainable in the synthesis of quinoid heteroaryls. It offers valuable insights into accessing these complex structures through efficient synthetic routes. Various strategies, including cyclization, heteroarylation, cycloisomerization, cyclo-condensation, intermolecular and intramolecular cascade reactions, are covered, highlighting the versatility of gold-catalyzed approaches. The comprehensive compilation of different synthetic approaches and elucidation of reaction mechanisms contribute to a deeper understanding of the field. This review paves the way for future advancements in synthesizing quinoid heteroaryls and their applications in drug discovery and materials science.
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Affiliation(s)
- Adnan Majeed
- Department of Chemistry, University of Agriculture Faisalabad Faisalabad-38000 Pakistan
| | - Ayesha Zafar
- Department of Chemistry, University of Agriculture Faisalabad Faisalabad-38000 Pakistan
| | - Zanira Mushtaq
- Department of Chemistry, University of Agriculture Faisalabad Faisalabad-38000 Pakistan
| | - Muhammad Adnan Iqbal
- Department of Chemistry, University of Agriculture Faisalabad Faisalabad-38000 Pakistan
- Organometallic and Coordination Chemistry Laboratory, University of Agriculture Faisalabad Faisalabad-38000 Pakistan
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Zhuo SY, Ye JL, Zheng X. Copper-catalyzed room-temperature cross-dehydrogenative coupling of secondary amides with terminal alkynes: a chemoselective synthesis of ynamides. Org Biomol Chem 2024; 22:1299-1309. [PMID: 38259138 DOI: 10.1039/d3ob02032k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
A copper-catalyzed aerobic oxidative cross-dehydrogenative coupling reaction between secondary amides and terminal alkynes has been developed. With the aid of ligands and 3 Å molecular sieves, ynamides can be efficiently synthesized at room temperature and conveniently scaled up. A legitimate mechanism involving nitrogen-centred radicals and copper trivalent intermediates has been proposed.
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Affiliation(s)
- Shuang-Yan Zhuo
- Xiamen Key Laboratory of Chiral Drugs, School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian 361102, China.
| | - Jian-Liang Ye
- Fujian Provincial Key Laboratory of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China.
| | - Xiao Zheng
- Xiamen Key Laboratory of Chiral Drugs, School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian 361102, China.
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Sun Q, Hüßler C, Kahle J, Mackenroth AV, Rudolph M, Krämer P, Oeser T, Hashmi ASK. Cascade Reactions of Aryl-Substituted Terminal Alkynes Involving in Situ-Generated α-Imino Gold Carbenes. Angew Chem Int Ed Engl 2023:e202313738. [PMID: 37882411 DOI: 10.1002/anie.202313738] [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: 09/14/2023] [Revised: 10/24/2023] [Accepted: 10/25/2023] [Indexed: 10/27/2023]
Abstract
An efficient, highly selective and divergent synthetic method to construct 2-substituted indoles and aryl-annulated carbazoles via the intermolecular generation of α-imino gold carbenes from terminal alkynes or diynes in combination with sulfilimines is disclosed. Importantly, the tandem reaction is proposed to proceed through an intermolecular gold carbene generation/C-H annulation followed by the activation of a second alkyne leading to 6-endo-dig cyclization, which is significantly different from previous dual activation or 1,6-carbene shift approaches for diyne systems. In the case of ortho-alkynylaniline as starting material, an unexpected regioselective formation of the indole moiety via the intermolecular path, instead of intramolecular hydroamination was discovered. This reactivity paved the way for a one-pot synthesis of the 11H-indolo [3,2-c] quinoline scaffold by exploiting the formed amino indole for a subsequent Pictet-Spengler reaction with aldehydes. The photophysical properties of the carbazoles indicated good violet-blue emission with quantum yields up to 40 %.
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Affiliation(s)
- Qiaoying Sun
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Christopher Hüßler
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Justin Kahle
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Alexandra V Mackenroth
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Matthias Rudolph
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Petra Krämer
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Thomas Oeser
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - A Stephen K Hashmi
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
- Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
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Ghosh T, Bhakta S. Advancements in Gold-Catalyzed Cascade Reactions to Access Carbocycles and Heterocycles: An Overview. CHEM REC 2023; 23:e202200225. [PMID: 36543388 DOI: 10.1002/tcr.202200225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 12/03/2022] [Indexed: 12/24/2022]
Abstract
This review summarizes recent developments (from 2006 to 2022) in numerous important and efficient carbo- and heterocycle generations using gold-catalyzed cascade protocols. Herein, methodologies involve selectivity, cost-effectiveness, and ease of product formation being controlled by the ligand as well as the counter anion, catalyst, substrate, and reaction conditions. Gold-catalyzed cascade reactions covered different strategies through the compilation of various approaches such as cyclization, hydroarylation, intermolecular and intramolecular cascade reactions, etc. This entitled reaction is also useful for the synthesis of spiro, fused, bridged carbo- and heterocycles.
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Affiliation(s)
- T Ghosh
- Department of Chemistry, Jadavpur University, Kolkata, 700 032, West Bengal, India.,Department of Applied Chemistry, Maulana Abul Kalam Azad University of Technology, West Bengal, Haringhata-741249, Nadia, West Bengal, India
| | - S Bhakta
- Department of Applied Chemistry, Maulana Abul Kalam Azad University of Technology, West Bengal, Haringhata-741249, Nadia, West Bengal, India
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