1
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Lee WCC, Wang DS, Zhu Y, Zhang XP. Iron(III)-based metalloradical catalysis for asymmetric cyclopropanation via a stepwise radical mechanism. Nat Chem 2023; 15:1569-1580. [PMID: 37679462 PMCID: PMC10842623 DOI: 10.1038/s41557-023-01317-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 08/08/2023] [Indexed: 09/09/2023]
Abstract
Metalloradical catalysis (MRC) exploits the metal-centred radicals present in open-shell metal complexes as one-electron catalysts for the generation of metal-stabilized organic radicals-key intermediates that control subsequent one-electron homolytic reactions. Cobalt(II) complexes of porphyrins, as stable 15e-metalloradicals with a well-defined low-spin d7 configuration, have dominated the ongoing development of MRC. Here, to broaden MRC beyond the use of Co(II)-based metalloradical catalysts, we describe systematic studies that establish the operation of Fe(III)-based MRC and demonstrate an initial application for asymmetric radical transformations. Specifically, we report that five-coordinate iron(III) complexes of porphyrins with an axial ligand, which represent another family of stable 15e-metalloradicals with a d5 configuration, are potent metalloradical catalysts for olefin cyclopropanation with different classes of diazo compounds via a stepwise radical mechanism. This work lays a foundation and mechanistic blueprint for future exploration of Fe(III)-based MRC towards the discovery of diverse stereoselective radical reactions.
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Affiliation(s)
- Wan-Chen Cindy Lee
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA, USA
| | - Duo-Sheng Wang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA, USA
| | - Yiling Zhu
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA, USA
| | - X Peter Zhang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA, USA.
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2
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Lee WCC, Wang J, Zhu Y, Zhang XP. Asymmetric Radical Bicyclization for Stereoselective Construction of Tricyclic Chromanones and Chromanes with Fused Cyclopropanes. J Am Chem Soc 2023; 145:11622-11632. [PMID: 37129381 PMCID: PMC10249947 DOI: 10.1021/jacs.3c01618] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Asymmetric radical bicyclization processes have been developed via metalloradical catalysis (MRC) to stereoselectively construct chiral chromanones and chromanes bearing fused cyclopropanes. Through optimization of a versatile D2-symmetric chiral amidoporphyrin ligand platform, a Co(II)-metalloradical system can homolytically activate both diazomalonates and α-aryldiazomethanes containing different alkene functionalities under mild conditions for effective radical bicyclization, delivering cyclopropane-fused tricyclic chromanones and chromanes, respectively, in high yields with excellent control of both diastereoselectivities and enantioselectivities. Combined computational and experimental studies, including the electron paramagnetic resonance (EPR) detection and 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) trapping of key radical intermediates, shed light on the working details of the underlying stepwise radical mechanisms of the Co(II)-catalyzed bicyclization processes. The two catalytic radical processes provide effective synthetic tools for stereoselective construction of valuable cyclopropane-fused chromanones and chromanes with newly generated contiguous stereogenic centers. As a specific demonstration of synthetic application, the Co(II)-catalyzed radical bicyclization has been employed as a key step for the first asymmetric total synthesis of the natural product (+)-Radulanin J.
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Affiliation(s)
- Wan-Chen Cindy Lee
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Jingyi Wang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Yiling Zhu
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - X Peter Zhang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
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3
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Wu Y, Ning Y, Han X, Liao P, Xia Y, Sivaguru P, Bi X. Silver-Catalyzed Vinylcarbene Insertion into C–C Bonds of 1,3-Diketones with Vinyl- N-triftosylhydrazones. Org Lett 2022; 24:8136-8141. [DOI: 10.1021/acs.orglett.2c03176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yong Wu
- Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China
| | - Yongquan Ning
- Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China
| | - Xinyue Han
- Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China
| | - Peiqiu Liao
- Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China
| | - Ying Xia
- Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China
| | - Paramasivam Sivaguru
- Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China
| | - Xihe Bi
- Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
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4
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Liu Z, Sivaguru P, Zanoni G, Bi X. N-Triftosylhydrazones: A New Chapter for Diazo-Based Carbene Chemistry. Acc Chem Res 2022; 55:1763-1781. [PMID: 35675648 DOI: 10.1021/acs.accounts.2c00186] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
ConspectusOver recent decades, N-sulfonylhydrazones have attracted significant attention in academic and industrial contexts owing to their ease of preparation, versatile reactivity, high stability, and practicality. In particular, the use of N-sulfonylhydrazones as precursors for diazo compounds has paved the way for innovative and original organic reactions that are otherwise difficult to achieve. Three key developments are noteworthy in the history of N-sulfonylhydrazone chemistry: (1) Bamford and Stevens initially disclosed the application of N-tosylhydrazones as a diazo source in 1952; (2) Aggarwal and co-workers investigated N-tosylhydrazone salts as diazo precursors for sulfur ylide-mediated asymmetric epoxidation and aziridination in 2001; and (3) Barluenga, Valdés and co-workers first reported Pd-catalyzed cross-coupling reactions with N-tosylhydrazones in 2007, thus introducing the direct use of N-tosylhydrazones in carbene transfer reactions. In the past 2 decades, the synthetic exploration of N-sulfonylhydrazones in carbene chemistry has increased remarkably. N-Tosylhydrazones are the most commonly used N-sulfonylhydrazones, but they are not easy to decompose and normally need relatively high temperatures (e.g., 90-110 °C). Temperature, as a key reaction parameter, has a significant influence on the selectivity and scope of organic reactions, especially the enantioselectivity. Aggarwal and co-workers have addressed this issue by using N-tosylhydrazone salts and achieved a limited number of asymmetric organic reactions, but the method is greatly limited because the salts must be freshly prepared or stored in the dark at -20 °C prior to use. Hence, easily decomposable N-sulfonylhydrazones, especially those capable of decomposing at low temperature, should open up new opportunities for the development of N-sulfonylhydrazone chemistry. Since 2014, our group has worked toward this goal and eventually identified N-2-(trifluoromethyl)benzenesulfonylhydrazone (i.e., N-triftosylhydrazone) as an efficient diazo surrogate that can decompose at temperatures as low as -40 °C. This allowed us to carry out a range of challenging synthetic transformations and to broaden the applications of some known reactions of great relevance.In this Account, we report our achievements in the application of N-triftosylhydrazones in carbene chemistry. On the basis of the reaction types, such applications can be categorized as (i) C(sp3)-H insertion reactions, (ii) defluorinative reactions of fluoroalkyl N-triftosylhydrazones, (iii) cycloaddition reactions with alkenes and alkynes, and (iv) asymmetric reactions. Additional applications in Doyle-Kirmse rearrangements and cross-coupling with isocyanides (ours) and benzyl chlorides (from the group of Xia) are also summarized in this Account concerning miscellaneous reactions. In terms of reaction efficiency, selectivity, and functional group tolerance, N-triftosylhydrazones are generally superior to traditional N-tosylhydrazones because of their easy decomposition. Mechanistic investigations by theoretical calculations provide insights into both the reaction mechanisms and the origin of selectivity. We hope that this Account will inspire broad interest and promote new progress in the synthetic exploration of easily decomposable N-sulfonylhydrazones.
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Affiliation(s)
- Zhaohong Liu
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | | | - Giuseppe Zanoni
- Department of Chemistry, University of Pavia, Pavia 27100, Italy
| | - Xihe Bi
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
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5
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Sahu MK, Jaiswal S, Pattanaik S, Gunanathan C. Base-Catalyzed Traceless Silylation and Deoxygenative Cyclization of Chalcones to Cyclopropanes. J Org Chem 2022; 87:6695-6709. [PMID: 35522975 DOI: 10.1021/acs.joc.2c00374] [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
Development of simple synthetic methods from readily available compounds to complex products is of utmost interest in modern synthesis. Catalytic synthesis of cyclopropanes is important for diverse chemical applications. We present a method for the transformation of readily accessible α,β-unsaturated ketones (chalcones) to cyclopropanes. A simple base, KOH, catalyzed the selective reduction of the enone carbonyl functionality, dehydrogenative silylation, and deoxygenative cyclization of chalcones to provide the cyclopropane products. Chalcones with extended conjugation and 4-chromanone-based substrates also provided the corresponding cyclopropanes. One-pot synthesis of cyclopropanes directly from industrial feedstock compounds such as ketones and aldehydes is also demonstrated using catalytic KOH for both intermolecular condensation and dehydrogenative silylation-deoxygenative intramolecular cyclization cascade.
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Affiliation(s)
- Manas Kumar Sahu
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar 752050, India
| | - Shubham Jaiswal
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar 752050, India
| | - Sandip Pattanaik
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar 752050, India
| | - Chidambaram Gunanathan
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar 752050, India
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6
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Rivers M, Carden RG, Widenhoefer RA. Substituent Effects and the Mechanism of Gold to Alkene Benzylidene Transfer Employing a Gold Sulfonium Benzylide Complex. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mitch Rivers
- Department of Chemistry, French Family Science Center, Duke University, Durham, North Carolina 27708, United States
| | - Robert G. Carden
- Department of Chemistry, French Family Science Center, Duke University, Durham, North Carolina 27708, United States
| | - Ross A. Widenhoefer
- Department of Chemistry, French Family Science Center, Duke University, Durham, North Carolina 27708, United States
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7
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Wang X, Ke J, Zhu Y, Deb A, Xu Y, Zhang XP. Asymmetric Radical Process for General Synthesis of Chiral Heteroaryl Cyclopropanes. J Am Chem Soc 2021; 143:11121-11129. [PMID: 34282613 PMCID: PMC8399893 DOI: 10.1021/jacs.1c04655] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A highly efficient catalytic method has been developed for asymmetric radical cyclopropanation of alkenes with in situ-generated α-heteroaryldiazomethanes via Co(II)-based metalloradical catalysis (MRC). Through fine-tuning the cavity-like environments of newly-synthesized D2-symmetric chiral amidoporphyrins as the supporting ligand, the optimized Co(II)-based metalloradical system is broadly applicable to α-pyridyl and other α-heteroaryldiazomethanes for asymmetric cyclopropanation of wide-ranging alkenes, including several types of challenging substrates. This new catalytic methodology provides a general access to valuable chiral heteroaryl cyclopropanes in high yields with excellent both diastereoselectivities and enantioselectivities. Combined computational and experimental studies further support the underlying stepwise radical mechanism of the Co(II)-based olefin cyclopropanation involving α- and γ-metalloalkyl radicals as the key intermediates.
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Affiliation(s)
- Xiaoxu Wang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Jing Ke
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Yiling Zhu
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Arghya Deb
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Yijie Xu
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - X Peter Zhang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
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8
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Cindy Lee WC, Wang DS, Zhang C, Xie J, Li B, Zhang XP. Asymmetric Radical Cyclopropanation of Dehydroaminocarboxylates: Stereoselective Synthesis of Cyclopropyl α-Amino Acids. Chem 2021; 7:1588-1601. [PMID: 34693072 DOI: 10.1016/j.chempr.2021.03.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A catalytic radical process has been developed for asymmetric cyclopropanation of dehydroaminocarboxylates with in situ-generated α-aryldiazomethanes via Co(II)-based metalloradical catalysis (MRC). Through fine-tuning the environments of D 2-symmetric chiral amidoporphyrin platform as the supporting ligands, the Co(II)-metalloradical system can effectively activate various α-aryldiazomethanes to cyclopropanate different dehydroaminocarboxylates under mild conditions, enabling the stereoselective synthesis of chiral cyclopropyl α-amino acid derivatives. In addition to high yields and excellent enantioselectivities, the Co(II)-catalyzed asymmetric radical cyclopropanation exhibits (Z)-diastereoselectivity, which is the opposite of uncatalyzed thermal reaction. Combined computational and experimental studies support a stepwise radical mechanism for the Co(II)-catalyzed cyclopropanation reaction. The resulting enantioenriched (Z)-α-amino-β-arylcyclopropanecarboxylates, as showcased for the efficient synthesis of dipeptides, may serve as unique non-proteinogenic amino acid building blocks for the design and preparation of novel peptides with restricted conformations.
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Affiliation(s)
- Wan-Chen Cindy Lee
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Duo-Sheng Wang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Congzhe Zhang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Jingjing Xie
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Bo Li
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - X Peter Zhang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
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9
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Wang Y, Wang H, Liu Z. Research Progress on EWG-Substituted N-Arylsulfonylhydrazones as the Diazo Compound Precursor. ACTA CHIMICA SINICA 2021. [DOI: 10.6023/a21040179] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Zhang J, Hao J, Huang Z, Han J, He Z. PIII-Mediated intramolecular cyclopropanation and metal-free synthesis of cyclopropane-fused heterocycles. Chem Commun (Camb) 2020; 56:10251-10254. [DOI: 10.1039/d0cc04086j] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The carbene-like reactivity of the Kukhtin–Ramirez adduct enables the first reductive intramolecular cyclopropanation, which provides easy access to highly functionalized cyclopropane-fused heterocycles.
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Affiliation(s)
- Jiayong Zhang
- State Key Laboratory of Elemento-Organic Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
- P. R. China
| | - Jiahang Hao
- State Key Laboratory of Elemento-Organic Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
- P. R. China
| | - Zhiqiang Huang
- State Key Laboratory of Elemento-Organic Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
- P. R. China
| | - Jie Han
- State Key Laboratory of Elemento-Organic Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
- P. R. China
| | - Zhengjie He
- State Key Laboratory of Elemento-Organic Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
- P. R. China
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11
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Lu T, Zhang X, Miao Z. Synthesis of methylene cyclopropane-fused chromenes and dihydroquinolines by sequential [4 + 2]- and [1 + 2]-annulation. Org Biomol Chem 2020; 18:3303-3311. [DOI: 10.1039/d0ob00389a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A base promoted sequential [4 + 2]- and [1 + 2]-annulation of 2-hydroxychalcones or 2-tosylaminochalcones with prop-2-ynylsulfonium salts was developed.
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Affiliation(s)
- Tianyu Lu
- State Key Laboratory and Institute of Elemento-Organic Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
- China
| | - Xuange Zhang
- State Key Laboratory and Institute of Elemento-Organic Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
- China
| | - Zhiwei Miao
- State Key Laboratory and Institute of Elemento-Organic Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
- China
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12
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Abstract
As readily accessible strained carbocycles, cyclopropenes show a diverse range of reactivities, and a lot of novel and useful transformations have been developed.
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Affiliation(s)
- Penghua Li
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals
- School of Chemistry & Molecular Engineering
- East China University of Science and Technology
- Shanghai 200237
- P. R. China
| | - Xiaoyu Zhang
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals
- School of Chemistry & Molecular Engineering
- East China University of Science and Technology
- Shanghai 200237
- P. R. China
| | - Min Shi
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals
- School of Chemistry & Molecular Engineering
- East China University of Science and Technology
- Shanghai 200237
- P. R. China
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13
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Damiano C, Sonzini P, Gallo E. Iron catalysts with N-ligands for carbene transfer of diazo reagents. Chem Soc Rev 2020; 49:4867-4905. [DOI: 10.1039/d0cs00221f] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This review provides an overview of the catalytic activity of iron complexes of nitrogen ligands in driving carbene transfers towards CC, C–H and X–H bonds. The reactivity of diazo reagents is discussed as well as the proposed reaction mechanisms.
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Affiliation(s)
| | - Paolo Sonzini
- Department of Chemistry
- University of Milan
- 20133 Milan
- Italy
| | - Emma Gallo
- Department of Chemistry
- University of Milan
- 20133 Milan
- Italy
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14
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Picher MI, Plietker B. Fe-Catalyzed Selective Cyclopropanation of Enynes under Photochemical or Thermal Conditions. Org Lett 2019; 22:340-344. [DOI: 10.1021/acs.orglett.9b04521] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marie-Idrissa Picher
- Institut für Organische Chemie, Universität Stuttgart, Pfaffenwaldring 55, DE-70569 Stuttgart, Germany
| | - Bernd Plietker
- Institut für Organische Chemie, Universität Stuttgart, Pfaffenwaldring 55, DE-70569 Stuttgart, Germany
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15
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Herndon JW. The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2018. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2019.213051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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16
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Green SP, Wheelhouse KM, Payne AD, Hallett JP, Miller PW, Bull JA. Thermal Stability and Explosive Hazard Assessment of Diazo Compounds and Diazo Transfer Reagents. Org Process Res Dev 2019; 24:67-84. [PMID: 31983869 PMCID: PMC6972035 DOI: 10.1021/acs.oprd.9b00422] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Indexed: 11/29/2022]
Abstract
Despite their wide use in academia as metal-carbene precursors, diazo compounds are often avoided in industry owing to concerns over their instability, exothermic decomposition, and potential explosive behavior. The stability of sulfonyl azides and other diazo transfer reagents is relatively well understood, but there is little reliable data available for diazo compounds. This work first collates available sensitivity and thermal analysis data for diazo transfer reagents and diazo compounds to act as an accessible reference resource. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and accelerating rate calorimetry (ARC) data for the model donor/acceptor diazo compound ethyl (phenyl)diazoacetate are presented. We also present a rigorous DSC dataset with 43 other diazo compounds, enabling direct comparison to other energetic materials to provide a clear reference work to the academic and industrial chemistry communities. Interestingly, there is a wide range of onset temperatures (T onset) for this series of compounds, which varied between 75 and 160 °C. The thermal stability variation depends on the electronic effect of substituents and the amount of charge delocalization. A statistical model is demonstrated to predict the thermal stability of differently substituted phenyl diazoacetates. A maximum recommended process temperature (T D24) to avoid decomposition is estimated for selected diazo compounds. The average enthalpy of decomposition (ΔH D) for diazo compounds without other energetic functional groups is -102 kJ mol-1. Several diazo transfer reagents are analyzed using the same DSC protocol and found to have higher thermal stability, which is in general agreement with the reported values. For sulfonyl azide reagents, an average ΔH D of -201 kJ mol-1 is observed. High-quality thermal data from ARC experiments shows the initiation of decomposition for ethyl (phenyl)diazoacetate to be 60 °C, compared to that of 100 °C for the common diazo transfer reagent p-acetamidobenzenesulfonyl azide (p-ABSA). The Yoshida correlation is applied to DSC data for each diazo compound to provide an indication of both their impact sensitivity (IS) and explosivity. As a neat substance, none of the diazo compounds tested are predicted to be explosive, but many (particularly donor/acceptor diazo compounds) are predicted to be impact-sensitive. It is therefore recommended that manipulation, agitation, and other processing of neat diazo compounds are conducted with due care to avoid impacts, particularly in large quantities. The full dataset is presented to inform chemists of the nature and magnitude of hazards when using diazo compounds and diazo transfer reagents. Given the demonstrated potential for rapid heat generation and gas evolution, adequate temperature control and cautious addition of reagents that begin a reaction are strongly recommended when conducting reactions with diazo compounds.
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Affiliation(s)
- Sebastian P Green
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, 80 Wood Lane, London W12 0BZ, U.K.,Department of Chemical Engineering, Imperial College London, South Kensington Campus, Exhibition Road, London SW7 2AZ, U.K
| | - Katherine M Wheelhouse
- API Chemistry, Product Development & Supply and Process Safety, Pilot Plant Operations, GlaxoSmithKline, GSK Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Andrew D Payne
- API Chemistry, Product Development & Supply and Process Safety, Pilot Plant Operations, GlaxoSmithKline, GSK Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Jason P Hallett
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, Exhibition Road, London SW7 2AZ, U.K
| | - Philip W Miller
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, 80 Wood Lane, London W12 0BZ, U.K
| | - James A Bull
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, 80 Wood Lane, London W12 0BZ, U.K
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17
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Milligan JA, Burns KL, Le AV, Polites VC, Wang ZJ, Molander GA, Kelly CB. Radical-Polar Crossover Annulation: A Platform for Accessing Polycyclic Cyclopropanes. Adv Synth Catal 2019; 362:242-247. [PMID: 34084099 DOI: 10.1002/adsc.201901051] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Photoredox-mediated radical/polar crossover (RPC) processes provide unique solutions to challenging annulations. Herein, we describe an approach to the cyclopropanation of olefins that are embedded within bicyclic scaffolds. Whereas these systems are notoriously recalcitrant toward classical cyclopropanation approaches, RPC cyclopropanation can be executed with ease, leading to polycarbocyclic and polyheterocyclic cyclopropanes. The cyclopropanation proceeds through a photoredox-enabled Giese-type radical addition followed by an intramolecular anionic substitution reaction on a neopentyl leaving group.
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Affiliation(s)
- John A Milligan
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, USA
| | - Kevin L Burns
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, P.O. Box 842006, Richmond, Virginia 23284, USA.,Medicines for All Institute, Virginia Commonwealth University, Biotech 8, 737 North Fifth Street, Richmond, Virginia, 23219, USA
| | - Anthony V Le
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, P.O. Box 842006, Richmond, Virginia 23284, USA.,Medicines for All Institute, Virginia Commonwealth University, Biotech 8, 737 North Fifth Street, Richmond, Virginia, 23219, USA
| | - Viktor C Polites
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, USA
| | - Zheng-Jun Wang
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, USA.,State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 41000, China
| | - Gary A Molander
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, USA
| | - Christopher B Kelly
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, P.O. Box 842006, Richmond, Virginia 23284, USA.,Medicines for All Institute, Virginia Commonwealth University, Biotech 8, 737 North Fifth Street, Richmond, Virginia, 23219, USA
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18
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Wang CY, Han JB, Wang L, Tang XY. Lewis Acid Catalyzed [4 + 2] Cycloaddition of N-Tosylhydrazones with ortho-Quinone Methides. J Org Chem 2019; 84:14258-14269. [PMID: 31599153 DOI: 10.1021/acs.joc.9b02040] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A formal [4 + 2] cycloaddition of N-tosylhydrazones with ortho-quinone methides was developed, affording the facile synthesis of diverse 1,3-oxazine derivatives under mild conditions. In this transformation, N-tosylhydrazones are used as a 1,2-dipole synthon under base-free conditions. Moreover, the substrate scope is broad, and the products are formed with high diastereoselectivities in most of the cases.
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Affiliation(s)
- Chun-Ying Wang
- School of Chemistry and Chemical Engineering, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Key Laboratory of Material Chemistry for Energy Conversion and Storage , Huazhong University of Science and Technology , 1037 Luoyu Road , Wuhan 430074 , People's Republic of China
| | - Jia-Bin Han
- School of Chemistry and Chemical Engineering, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Key Laboratory of Material Chemistry for Energy Conversion and Storage , Huazhong University of Science and Technology , 1037 Luoyu Road , Wuhan 430074 , People's Republic of China
| | - Long Wang
- School of Chemistry and Chemical Engineering, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Key Laboratory of Material Chemistry for Energy Conversion and Storage , Huazhong University of Science and Technology , 1037 Luoyu Road , Wuhan 430074 , People's Republic of China
| | - Xiang-Ying Tang
- School of Chemistry and Chemical Engineering, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Key Laboratory of Material Chemistry for Energy Conversion and Storage , Huazhong University of Science and Technology , 1037 Luoyu Road , Wuhan 430074 , People's Republic of China
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19
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Phipps EJT, Rovis T. Rh(III)-Catalyzed C-H Activation-Initiated Directed Cyclopropanation of Allylic Alcohols. J Am Chem Soc 2019; 141:6807-6811. [PMID: 30998324 DOI: 10.1021/jacs.9b02156] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We have developed a Rh(III)-catalyzed diastereoselective [2+1] annulation onto allylic alcohols initiated by alkenyl C-H activation of N-enoxyphthalimides to furnish substituted cyclopropyl-ketones. Notably, the traceless oxyphthalimide handle serves three functions: directing C-H activation, oxidation of Rh(III), and, collectively with the allylic alcohol, in directing cyclopropanation to control diastereoselectivity. Allylic alcohols are shown to be highly reactive olefin coupling partners leading to a directed diastereoselective cyclopropanation reaction, providing products not accessible by other routes.
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Affiliation(s)
- Erik J T Phipps
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Tomislav Rovis
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
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20
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Allouche EMD, Charette AB. Non-stabilized diazoalkane synthesis via the oxidation of free hydrazones by iodosylbenzene and application in in situ MIRC cyclopropanation. Chem Sci 2019; 10:3802-3806. [PMID: 31015921 PMCID: PMC6457201 DOI: 10.1039/c8sc05558k] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 02/18/2019] [Indexed: 12/15/2022] Open
Abstract
Electron-rich alkyl diazo compounds are powerful reagents in organic synthesis, but the risks associated with their toxicity and instability often limit their uses. Herein we describe an efficient, easy-to-handle and safe batch protocol for the in situ generation and cyclopropanation of these highly reactive non-stabilized diazoalkanes through the oxidation of free hydrazones using iodosylbenzene. Numerous substituted cyclopropanes have been synthesized using this methodology, including various gem-dimethylcyclopropanes of particular interest in medicinal chemistry.
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Affiliation(s)
- Emmanuelle M D Allouche
- Department of Chemistry , Université de Montréal , P. O. Box 6128 Station Downtown , Montreal , Quebec , H3C 3J7 Canada .
| | - André B Charette
- Department of Chemistry , Université de Montréal , P. O. Box 6128 Station Downtown , Montreal , Quebec , H3C 3J7 Canada .
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21
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Gu H, Huang S, Lin X. Iron-catalyzed asymmetric intramolecular cyclopropanation reactions using chiral tetramethyl-1,1′-spirobiindane-based bisoxazoline (TMSI-BOX) ligands. Org Biomol Chem 2019; 17:1154-1162. [DOI: 10.1039/c8ob03065k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fe complexes of TMSI-BOX based on the tetramethyl-1,1′-spirobiindane backbone have been developed and applied in catalytic highly enantioselective intramolecular cyclopropanation reactions.
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Affiliation(s)
- Haorui Gu
- Laboratory of Asymmetric Catalysis and Synthesis
- Department of Chemistry
- Zhejiang University
- Hangzhou 310027
- China
| | - Shaoying Huang
- Laboratory of Asymmetric Catalysis and Synthesis
- Department of Chemistry
- Zhejiang University
- Hangzhou 310027
- China
| | - Xufeng Lin
- Laboratory of Asymmetric Catalysis and Synthesis
- Department of Chemistry
- Zhejiang University
- Hangzhou 310027
- China
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