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Becker A, Bauer F, Breit B. Rhodium-Catalyzed Enantioselective Cyclization of 2-Allenylbenzoxazoles. Org Lett 2024. [PMID: 38506278 DOI: 10.1021/acs.orglett.4c00526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
The enantioselective rhodium-catalyzed cyclization of 2-allenylbenzoxazoles to the corresponding vinyl-functionalized, fused heterocyclic structures is reported. The presented method offers several advantages, including the use of low catalyst loadings, commercially available catalyst precursors, and mild reaction conditions. Due to its broad scope, scalability, and valuable products, we consider this methodology to be a useful tool for the construction of benzoxazole-containing building blocks.
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Affiliation(s)
- Antonia Becker
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany
| | - Felix Bauer
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany
| | - Bernhard Breit
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany
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2
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Song X, Qin W, Wang X, Luo G, Ni Q. Bifunctional Squaramide-Catalyzed Asymmetric Cascade Reaction of Benzothiazoles with 2-Nitroallylic Acetates or Nitroenynes. Org Lett 2023; 25:9164-9169. [PMID: 38097282 DOI: 10.1021/acs.orglett.3c03692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2023]
Abstract
We describe here an organocatalytic asymmetric cascade formal [3 + 3] cycloaddition of benzothiazoles with 2-nitroallylic acetates and nitroenynes. This dearomative methodology provided a facile and efficient strategy for the construction of a broad range of valuable benzothiazolopyridines bearing two adjacent stereogenic centers in moderate to good yields with good to excellent stereocontrol.
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Affiliation(s)
- Xiaoxiao Song
- Key Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecule-Based Materials (State Key Laboratory Cultivation Base), College of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241002, P. R. China
| | - Wei Qin
- Key Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecule-Based Materials (State Key Laboratory Cultivation Base), College of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241002, P. R. China
| | - Xuyang Wang
- Key Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecule-Based Materials (State Key Laboratory Cultivation Base), College of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241002, P. R. China
| | - Gen Luo
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Qijian Ni
- Key Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecule-Based Materials (State Key Laboratory Cultivation Base), College of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241002, P. R. China
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3
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Li Y, Huang X, Peng S, Wang J, Lang M. NHC-catalyzed [3 + 3] cycloaddition of α-bromoenals with nitroketene aminals or nitroketene N, S-acetals: synthesis of nitro-containing dihydropyridin-2-ones. Org Biomol Chem 2023; 21:1399-1403. [PMID: 36723143 DOI: 10.1039/d2ob02334b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
An N-heterocyclic carbene (NHC)-catalyzed [3 + 3] cycloaddition of α-bromoenals with nitroketene aminals or nitroketene N,S-acetals has been developed. This methodology provides an efficient strategy for the construction of valuable nitro-containing heterocyclic compounds. This protocol features mild reaction conditions, easily available starting materials, broad substrate scope and easy scalability.
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Affiliation(s)
- Yarui Li
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, People's Republic of China. .,International Healthcare Innovation Institute (Jiangmen), Jiangmen 529040, People's Republic of China
| | - Xiaoxia Huang
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, People's Republic of China. .,International Healthcare Innovation Institute (Jiangmen), Jiangmen 529040, People's Republic of China
| | - Shiyong Peng
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, People's Republic of China.
| | - Jian Wang
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, People's Republic of China.
| | - Ming Lang
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, People's Republic of China. .,International Healthcare Innovation Institute (Jiangmen), Jiangmen 529040, People's Republic of China
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De Risi C, Brandolese A, Di Carmine G, Ragno D, Massi A, Bortolini O. Oxidative N-Heterocyclic Carbene Catalysis. Chemistry 2023; 29:e202202467. [PMID: 36205918 PMCID: PMC10099058 DOI: 10.1002/chem.202202467] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Indexed: 11/05/2022]
Abstract
N-Heterocyclic carbene (NHC) catalysis is a by now consolidated organocatalytic platform for a number of synthetic (asymmetric) transformations via diverse reaction modes/intermediates. In addition to the typical umpolung processes involving acyl anion/homoenolate equivalent species, implementation of protocols under oxidative conditions greatly expands the possibilities of this methodology. Oxidative NHC-catalysis allows for oxidative and oxygenative transformations through specific manipulations of Breslow-type species depending upon the oxidant used (external oxidant or O2 /air), the derived NHC-bound intermediates paving the way to non-umpolung processes through activation of carbon atoms and heteroatoms. This review is intended to update the state of the art in oxidative NHC-catalyzed reactions that appeared in the literature from 2014 to present, with a strong focus to crucial intermediates and their mechanistic implications.
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Affiliation(s)
- Carmela De Risi
- Dipartimento di Scienze Chimiche, Farmaceutiche ed Agrarie, Università di Ferrara, Via L. Borsari, 46, 44121, Ferrara, Italy
| | - Arianna Brandolese
- Dipartimento di Scienze dell'Ambiente e della Prevenzione, Università di Ferrara, Via L. Borsari, 46, 44121, Ferrara, Italy
| | - Graziano Di Carmine
- Dipartimento di Scienze Chimiche, Farmaceutiche ed Agrarie, Università di Ferrara, Via L. Borsari, 46, 44121, Ferrara, Italy
| | - Daniele Ragno
- Dipartimento di Scienze Chimiche, Farmaceutiche ed Agrarie, Università di Ferrara, Via L. Borsari, 46, 44121, Ferrara, Italy
| | - Alessandro Massi
- Dipartimento di Scienze Chimiche, Farmaceutiche ed Agrarie, Università di Ferrara, Via L. Borsari, 46, 44121, Ferrara, Italy
| | - Olga Bortolini
- Dipartimento di Scienze dell'Ambiente e della Prevenzione, Università di Ferrara, Via L. Borsari, 46, 44121, Ferrara, Italy
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5
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Chu Y, Wu M, Hu F, Zhou P, Cao Z, Hui XP. N-Heterocyclic Carbene-Catalyzed Atroposelective Synthesis of Pyrrolo[3,4- b]pyridines with Configurationally Stable C-N Axial Chirality. Org Lett 2022; 24:3884-3889. [PMID: 35609114 DOI: 10.1021/acs.orglett.2c01519] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The first atroposelective synthesis of pyrrolo[3,4-b]pyridines catalyzed by N-heterocyclic carbene has been achieved. A wide range of chiral atropisomers of pyrrolo[3,4-b]pyridines were obtained in high yields with excellent enantioselectivities (96-99% enantiomeric excess). The experimental results and density functional theory calculations showed that the C-N axial chirality of the product had high thermal stability.
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Affiliation(s)
- Yunpeng Chu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China
| | - Meng Wu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China
| | - Fang Hu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China
| | - Panpan Zhou
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China
| | - Zhengqiang Cao
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China
| | - Xin-Ping Hui
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China
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