1
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Hilche T, Krebs T, Weißbarth H, Lang F, Schnakenburg G, Gansäuer A. Enantio- and Diastereomerically Pure Titanocenes by Dynamic Conformational Locking. Chemistry 2023; 29:e202301645. [PMID: 37283199 DOI: 10.1002/chem.202301645] [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: 06/01/2023] [Revised: 06/05/2023] [Accepted: 06/05/2023] [Indexed: 06/08/2023]
Abstract
The synthesis of enantiomerically pure titanocenes is limited to cases with enantiomerically pure substituents at the cyclopentadienyl ligands and to ansa-titanocenes. For the latter complexes, the use of achiral ligands requires a resolution of enantiomers and frequently also a separation of the diastereoisomers obtained after metalation. Here, we introduce a new synthetic method that relies on the use of enantiomerically pure camphorsulfonate (CSA) ligands as control elements for the absolute and relative configuration of titanocene complexes. Starting from the conformationally flexible (RC5 H4 )2 TiCl2 , the desired conformationally locked and hence enantio- and diastereomerically pure complexes (RC5 H4 )2 Ti(CSA)2 are obtained in just two steps. According to X-ray crystallography the (RC5 H4 )2 Ti fragment is essentially C2 -symmetric and nuclear magnetic resonance displays overall C2 -symmetry. We applied density functional theory methods to unravel the dynamics of the complexes and the mechanisms and selectivities of their formation.
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Affiliation(s)
- Tobias Hilche
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Tim Krebs
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Hendrik Weißbarth
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Fabian Lang
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Gregor Schnakenburg
- Institut für Anorganische Chemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
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2
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Höthker S, Gansäuer A. Formal Anti-Markovnikov Addition of Water to Olefins by Titanocene-Catalyzed Epoxide Hydrosilylation: From Stoichiometric to Sustainable Catalytic Reactions. GLOBAL CHALLENGES (HOBOKEN, NJ) 2023; 7:2200240. [PMID: 37483422 PMCID: PMC10362118 DOI: 10.1002/gch2.202200240] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/21/2023] [Indexed: 07/25/2023]
Abstract
Here, the evolution of the titanocene-catalyzed hydrosilylation of epoxides that yields the corresponding anti-Markovnikov alcohols is summarized. The study focuses on aspects of sustainability, efficient catalyst activation, and stereoselectivity. The latest variant of the reaction employs polymethylhydrosiloxane (PMHS), a waste product of the Müller-Rochow process as terminal reductant, features an efficient catalyst activation with benzylMgBr and the use of the bench stable Cp2TiCl2 as precatalyst. The combination of olefin epoxidation and epoxide hydrosilylation provides a uniquely efficient approach to the formal anti-Markovnikov addition of H2O to olefins.
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Affiliation(s)
- Sebastian Höthker
- Kekulé‐Institut für Organische Chemie und BiochemieRheinische Friedrich‐Wilhelms‐Universität BonnGerhard‐Domagk‐Straße 153121BonnGermany
| | - Andreas Gansäuer
- Kekulé‐Institut für Organische Chemie und BiochemieRheinische Friedrich‐Wilhelms‐Universität BonnGerhard‐Domagk‐Straße 153121BonnGermany
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3
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Tulyabaeva LI, Salakhutdinov RR, Tulyabaev AR, Tyumkina TV, Abdullin MF. Reaction of Methylidenecycloalkanes with BF3·THF Catalyzed by Cp2TiCl2. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2022. [DOI: 10.1134/s1070428022120296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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4
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Watson I, Zhou Y, Ferguson M, Rivard E. Group 4 Transition Metal Complexes with Anionic N‐Heterocyclic Olefin Ligands. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202200082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
| | | | | | - Eric Rivard
- University of Alberta Deptm. of Chemistry 11227 Saskatchewan Dr. T6G 2G2 Edmonton CANADA
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5
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Wang J, Xie J, Lee WCC, Wang DS, Zhang XP. Radical differentiation of two ester groups in unsymmetrical diazomalonates for highly asymmetric olefin cyclopropanation. CHEM CATALYSIS 2022; 2:330-344. [PMID: 35494099 PMCID: PMC9049825 DOI: 10.1016/j.checat.2021.11.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Diazomalonates have been demonstrated as effective metalloradicophiles for asymmetric radical olefin cyclopropanation via Co(II)-metalloradical catalysis (MRC). Supported by D 2-symmetric chiral amidoporphyrin ligand, Co(II)-based metalloradical system can efficiently activate unsymmetrical methyl phenyl diazomalonate (MPDM) with effective differentiation of the two ester groups for asymmetric cyclopropanation, enabling stereoselective construction of 1,1-cyclopropanediesters bearing two contiguous chiral centers, including all-carbon quaternary stereogenic center. The Co(II)-catalyzed asymmetric cyclopropanation, which operates at room temperature without slow addition of the diazo compound, is generally applicable to broad-ranging olefins and tolerates various functionalities, providing a streamlined synthesis of chiral 1,1-cyclopropanediesters in high yields with both high diastereoselectivity and enantioselectivity. Combined computational and experimental studies support the underlying stepwise radical mechanism for Co(II)-catalyzed cyclopropanation. In addition to functioning as 1,3-dipoles for forming five-membered structures, enantioenriched (E)-1,1-cyclopropanediesters serve as useful building blocks for stereoselective synthesis of different cyclopropane derivatives. In addition, the enantioenriched (E)-1,1-cyclopropanediesters can be stereoselectively converted to (Z)-diastereomers.
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Affiliation(s)
- Jingyi Wang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA
| | - Jingjing Xie
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA
| | - Wan-Chen Cindy Lee
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA
| | - Duo-Sheng Wang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA
| | - X. Peter Zhang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA
- Lead contact
- Correspondence:
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6
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Ke J, Lee WCC, Wang X, Wang Y, Wen X, Zhang XP. Metalloradical Activation of In Situ-Generated α-Alkynyldiazomethanes for Asymmetric Radical Cyclopropanation of Alkenes. J Am Chem Soc 2022; 144:2368-2378. [PMID: 35099966 PMCID: PMC9032462 DOI: 10.1021/jacs.1c13154] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
α-Alkynyldiazomethanes, generated in situ from the corresponding sulfonyl hydrazones in the presence of a base, can serve as effective metalloradicophiles in Co(II)-based metalloradical catalysis (MRC) for asymmetric cyclopropanation of alkenes. With D2-symmetric chiral amidoporphyrin 2,6-DiMeO-QingPhyrin as the optimal supporting ligand, the Co(II)-based metalloradical system can efficiently activate different α-alkynyldiazomethanes at room temperature for highly asymmetric cyclopropanation of a broad range of alkenes. This catalytic radical process provides a general synthetic tool for stereoselective construction of alkynyl cyclopropanes in high yields with high both diastereoselectivity and enantioselectivity. Combined computational and experimental studies offer several lines of evidence in support of the underlying stepwise radical mechanism for the Co(II)-catalyzed olefin cyclopropanation involving a unique α-metalloradical intermediate that is associated with two resonance forms of α-Co(III)-propargyl radical and γ-Co(III)-allenyl radical. The resulting enantioenriched alkynyl cyclopropanes, as showcased with several stereospecific transformations, may serve as valuable chiral building blocks for stereoselective organic synthesis.
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Affiliation(s)
- Jing Ke
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Wan-Chen Cindy Lee
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Xiaoxu Wang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Yong Wang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Xin Wen
- 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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7
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Zhou M, Wolzak LA, Li Z, de Zwart FJ, Mathew S, de Bruin B. Catalytic Synthesis of 1 H-2-Benzoxocins: Cobalt(III)-Carbene Radical Approach to 8-Membered Heterocyclic Enol Ethers. J Am Chem Soc 2021; 143:20501-20512. [PMID: 34802239 PMCID: PMC8662738 DOI: 10.1021/jacs.1c10927] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Indexed: 12/30/2022]
Abstract
The metallo-radical activation of ortho-allylcarbonyl-aryl N-arylsulfonylhydrazones with the paramagnetic cobalt(II) porphyrin catalyst [CoII(TPP)] (TPP = tetraphenylporphyrin) provides an efficient and powerful method for the synthesis of novel 8-membered heterocyclic enol ethers. The synthetic protocol is versatile and practical and enables the synthesis of a wide range of unique 1H-2-benzoxocins in high yields. The catalytic cyclization reactions proceed with excellent chemoselectivities, have a high functional group tolerance, and provide several opportunities for the synthesis of new bioactive compounds. The reactions are shown to proceed via cobalt(III)-carbene radical intermediates, which are involved in intramolecular hydrogen transfer (HAT) from the allylic position to the carbene radical, followed by a near-barrierless radical rebound step in the coordination sphere of cobalt. The proposed mechanism is supported by experimental observations, density functional theory (DFT) calculations, and spin trapping experiments.
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Affiliation(s)
- Minghui Zhou
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Lukas A. Wolzak
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Zirui Li
- Department
of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333
CC Leiden, The Netherlands
| | - Felix J. de Zwart
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Simon Mathew
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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8
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Younas SL, Streuff J. Kinetic Analysis Uncovers Hidden Autocatalysis and Inhibition Pathways in Titanium(III)-Catalyzed Ketone-Nitrile Couplings. ACS Catal 2021. [DOI: 10.1021/acscatal.1c02870] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Sara L. Younas
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany
| | - Jan Streuff
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany
- Department of Chemistry—BMC, Uppsala University, Husargatan 3, 75237 Uppsala, Sweden
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9
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Xie J, Xu P, Zhu Y, Wang J, Lee WCC, Zhang XP. New Catalytic Radical Process Involving 1,4-Hydrogen Atom Abstraction: Asymmetric Construction of Cyclobutanones. J Am Chem Soc 2021; 143:11670-11678. [PMID: 34292709 PMCID: PMC8399868 DOI: 10.1021/jacs.1c04968] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
While alkyl radicals have been well demonstrated to undergo both 1,5- and 1,6-hydrogen atom abstraction (HAA) reactions, 1,4-HAA is typically a challenging process both entropically and enthalpically. Consequently, chemical transformations based on 1,4-HAA have been scarcely developed. Guided by the general mechanistic principles of metalloradical catalysis (MRC), 1,4-HAA has been successfully incorporated as a key step, followed by 4-exo-tet radical substitution (RS), for the development of a new catalytic radical process that enables asymmetric 1,4-C-H alkylation of diazoketones for stereoselective construction of cyclobutanone structures. The key to success is the optimization of the Co(II)-based metalloradical catalyst through judicious modulation of D2-symmetric chiral amidoporphyrin ligand to adopt proper steric, electronic, and chiral environments that can utilize a network of noncovalent attractive interactions for effective activation of the substrate and subsequent radical intermediates. Supported by an optimal chiral ligand, the Co(II)-based metalloradical system, which operates under mild conditions, is capable of 1,4-C-H alkylation of α-aryldiazoketones with varied electronic and steric properties to construct chiral α,β-disubstituted cyclobutanones in good to high yields with high diastereoselectivities and enantioselectivities, generating dinitrogen as the only byproduct. Combined computational and experimental studies have shed light on the mechanistic details of the new catalytic radical process, including the revelation of facile 1,4-HAA and 4-exo-tet-RS steps. The resulting enantioenriched α,β-disubstituted cyclobutanones, as showcased with several enantiospecific transformations to other types of cyclic structures, may find useful applications in stereoselective organic synthesis.
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Affiliation(s)
- Jingjing Xie
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Pan Xu
- 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
| | - Jingyi Wang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Wan-Chen Cindy Lee
- 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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10
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Wood DP, Guan W, Lin S. Titanium and Cobalt Bimetallic Radical Redox Relay for the Isomerization of N-Bz Aziridines to Allylic Amides. SYNTHESIS-STUTTGART 2021; 53:4213-4220. [PMID: 34764520 PMCID: PMC8579959 DOI: 10.1055/s-0037-1610779] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Herein a bimetallic radical redox-relay strategy is employed to generate alkyl radicals under mild conditions with titanium(III) catalysis and terminated via hydrogen atom transfer with cobalt(II) catalysis to enact base-free isomerizations of N-Bz aziridines to N-Bz allylic amides. This reaction provides an alternative strategy for the synthesis of allylic amides from alkenes via a three-step sequence to accomplish a formal transpositional allylic amination.
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Affiliation(s)
- Devin P Wood
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Weiyang Guan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Song Lin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
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11
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Zhang C, Wang DS, Lee WCC, McKillop AM, Zhang XP. Controlling Enantioselectivity and Diastereoselectivity in Radical Cascade Cyclization for Construction of Bicyclic Structures. J Am Chem Soc 2021; 143:11130-11140. [PMID: 34260202 PMCID: PMC8399859 DOI: 10.1021/jacs.1c04719] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Radical cascade cyclization reactions are highly attractive synthetic tools for the construction of polycyclic molecules in organic synthesis. While it has been successfully implemented in diastereoselective synthesis of natural products and other complex compounds, radical cascade cyclization faces a major challenge of controlling enantioselectivity. As the first application of metalloradical catalysis (MRC) for controlling enantioselectivity as well as diastereoselectivity in radical cascade cyclization, we herein report the development of a Co(II)-based catalytic system for asymmetric radical bicyclization of 1,6-enynes with diazo compounds. Through the fine-tuning of D2-symmetric chiral amidoporphyrins as the supporting ligands, the Co(II)-catalyzed radical cascade process, which proceeds in a single operation under mild conditions, enables asymmetric construction of multisubstituted cyclopropane-fused tetrahydrofurans bearing three contiguous stereogenic centers, including two all-carbon quaternary centers, in high yields with excellent stereoselectivities. Combined computational and experimental studies have shed light on the underlying stepwise radical mechanism for this new Co(II)-based cascade bicyclization that involves the relay of several Co-supported C-centered radical intermediates, including α-, β-, γ-, and ε-metalloalkyl radicals. The resulting enantioenriched cyclopropane-fused tetrahydrofurans that contain a trisubstituted vinyl group at the bridgehead, as showcased in several stereospecific transformations, may serve as useful intermediates for stereoselective organic synthesis. The successful demonstration of this new asymmetric radical process via Co(II)-MRC points out a potentially general approach for controlling enantioselectivity as well as diastereoselectivity in synthetically attractive radical cascade reactions.
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Affiliation(s)
- Congzhe Zhang
- 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
| | - Wan-Chen Cindy Lee
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Alexander M McKillop
- 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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12
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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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13
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Zhang Z, Stückrath JB, Grimme S, Gansäuer A. Titanocene‐Catalyzed [2+2] Cycloaddition of Bisenones and Comparison with Photoredox Catalysis and Established Methods. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Zhenhua Zhang
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard-Domagk-Strasse 1 53121 Bonn Germany
| | - Julius B. Stückrath
- Mulliken Center for Theoretical Chemistry Institut für Physikalische und Theoretische Chemie Universität Bonn Beringstrasse 4 53115 Bonn Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry Institut für Physikalische und Theoretische Chemie Universität Bonn Beringstrasse 4 53115 Bonn Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard-Domagk-Strasse 1 53121 Bonn Germany
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14
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Zhang Z, Stückrath JB, Grimme S, Gansäuer A. Titanocene-Catalyzed [2+2] Cycloaddition of Bisenones and Comparison with Photoredox Catalysis and Established Methods. Angew Chem Int Ed Engl 2021; 60:14339-14344. [PMID: 33871126 PMCID: PMC8251790 DOI: 10.1002/anie.202102739] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Indexed: 12/17/2022]
Abstract
Cp2 Ti(TFA) is a broadly applicable catalyst for the [2+2] cycloaddition of bisenones by inner-sphere electron transfer. The attractiveness of this mechanism is shown by comparison with outer-sphere ET methods. DFT calculations show that the reaction proceeds through a unique unfavorable 5-exo (the rate-determining step) and a favorable 4-exo cyclization.
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Affiliation(s)
- Zhenhua Zhang
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Strasse 153121BonnGermany
| | - Julius B. Stückrath
- Mulliken Center for Theoretical ChemistryInstitut für Physikalische und Theoretische ChemieUniversität BonnBeringstrasse 453115BonnGermany
| | - Stefan Grimme
- Mulliken Center for Theoretical ChemistryInstitut für Physikalische und Theoretische ChemieUniversität BonnBeringstrasse 453115BonnGermany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Strasse 153121BonnGermany
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15
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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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16
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Sumiyama K, Toriumi N, Iwasawa N. Use of Isopropyl Alcohol as a Reductant for Catalytic Dehydoxylative Dimerization of Benzylic Alcohols Utilizing Ti−O Bond Photohomolysis. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100286] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Keiichi Sumiyama
- Department of Chemistry Tokyo Institute of Technology O-okayama, Meguro-ku Tokyo 152-8551 Japan
| | - Naoyuki Toriumi
- Department of Chemistry Tokyo Institute of Technology O-okayama, Meguro-ku Tokyo 152-8551 Japan
| | - Nobuharu Iwasawa
- Department of Chemistry Tokyo Institute of Technology O-okayama, Meguro-ku Tokyo 152-8551 Japan
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17
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Riart-Ferrer X, Sang P, Tao J, Xu H, Jin LM, Lu H, Cui X, Wojtas L, Zhang XP. Metalloradical activation of carbonyl azides for enantioselective radical aziridination. Chem 2021; 7:1120-1134. [PMID: 33869888 DOI: 10.1016/j.chempr.2021.03.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Organic azides have been increasingly employed as nitrogen sources for catalytic olefine aziridination due to their ease of preparation and generation of benign N2 as the only byproduct. Among common organic azides, carbonyl azides have not been previously demonstrated as effective nitrogen sources for intermolecular olefin aziridination despite the synthetic utilities of N-carbonyl aziridines. As a new application of metalloradical catalysis, we have developed a catalytic system that can effectively employ the carbonyl azide TrocN3 for highly asymmetric aziridination of alkenes at room temperature. The resulting enantioenriched N-Trocaziridines have been shown as valuable chiral synthons for stereoselective synthesis of other chiral aziridines and various chiral amines. The Co(II)-based metalloradical system, which proceeds with distinctive stepwise radical mechanism, may provide a general method for asymmetric synthesis of chiral aziridines from alkenes with organic azides.
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Affiliation(s)
- Xavier Riart-Ferrer
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA
- These authors contributed equally
| | - Peng Sang
- Department of Chemistry, University of South Florida, Tampa, FL 33620, USA
- These authors contributed equally
| | - Jingran Tao
- Department of Chemistry, University of South Florida, Tampa, FL 33620, USA
- These authors contributed equally
| | - Hao Xu
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA
| | - Li-Mei Jin
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA
| | - Hongjian Lu
- Department of Chemistry, University of South Florida, Tampa, FL 33620, USA
| | - Xin Cui
- Department of Chemistry, University of South Florida, Tampa, FL 33620, USA
| | - Lukasz Wojtas
- Department of Chemistry, University of South Florida, Tampa, FL 33620, USA
| | - X Peter Zhang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA
- Lead contact
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18
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Hilche T, Reinsberg PH, Klare S, Liedtke T, Schäfer L, Gansäuer A. Design Platform for Sustainable Catalysis with Radicals: Electrochemical Activation of Cp 2 TiCl 2 for Catalysis Unveiled. Chemistry 2021; 27:4903-4912. [PMID: 33085978 PMCID: PMC7986168 DOI: 10.1002/chem.202004519] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Indexed: 12/17/2022]
Abstract
The combination of synthesis, rotating ring-disk electrode (RRDE) and cyclic voltammetry (CV) measurements, and computational investigations with the aid of DFT methods shows how a thiourea, a squaramide, and a bissulfonamide as additives affect the Eq Cr equilibrium of Cp2 TiCl2 . We have, for the first time, provided quantitative data for the Eq Cr equilibrium and have determined the stoichiometry of adduct formation of [Cp2 Ti(III)Cl2 ]- , [Cp2 Ti(III)Cl] and [Cp2 Ti(IV)Cl2 ] and the additives. By studying the structures of the complexes formed by DFT methods, we have established the Gibbs energies and enthalpies of complex formation as well as the adduct structures. The results not only demonstrate the correctness of our use of the Eq Cr equilibrium as predictor for sustainable catalysis. They are also a design platform for the development of novel additives in particular for enantioselective catalysis.
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Affiliation(s)
- Tobias Hilche
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Straße 153121BonnGermany
| | - Philip H. Reinsberg
- Institut für Physikalische und Theoretische Chemie, Universität BonnRömerstraße 16453117BonnGermany
| | - Sven Klare
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Straße 153121BonnGermany
| | - Theresa Liedtke
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Straße 153121BonnGermany
| | - Luise Schäfer
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Straße 153121BonnGermany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Straße 153121BonnGermany
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19
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Funk P, Richrath RB, Bohle F, Grimme S, Gansäuer A. Oxidation Under Reductive Conditions: From Benzylic Ethers to Acetals with Perfect Atom-Economy by Titanocene(III) Catalysis. Angew Chem Int Ed Engl 2021; 60:5482-5488. [PMID: 33245820 PMCID: PMC7986230 DOI: 10.1002/anie.202013561] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Indexed: 12/19/2022]
Abstract
Described here is a titanocene-catalyzed reaction for the synthesis of acetals and hemiaminals from benzylic ethers and benzylic amines, respectively, with pendant epoxides. The reaction proceeds by catalysis in single-electron steps. The oxidative addition comprises an epoxide opening. An H-atom transfer, to generate a benzylic radical, serves as a radical translocation step, and an organometallic oxygen rebound as a reductive elimination. The reaction mechanism was studied by high-level dispersion corrected hybrid functional DFT with implicit solvation. The low-energy conformational space was searched by the efficient CREST program. The stereoselectivity was deduced from the lowest lying benzylic radical structures and their conformations are controlled by hyperconjugative interactions and steric interactions between the titanocene catalyst and the aryl groups of the substrate. An interesting mechanistic aspect is that the oxidation of the benzylic center occurs under reducing conditions.
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Affiliation(s)
- Pierre Funk
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Str. 153121BonnGermany
| | - Ruben B. Richrath
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Str. 153121BonnGermany
| | - Fabian Bohle
- Mulliken Center for Theoretical ChemistryInstitut für Physikalische und Theoretische ChemieUniversität BonnBeringstraße 453115BonnGermany
| | - Stefan Grimme
- Mulliken Center for Theoretical ChemistryInstitut für Physikalische und Theoretische ChemieUniversität BonnBeringstraße 453115BonnGermany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Str. 153121BonnGermany
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20
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Tang CK, Li YZ, Zhou ZJ, Ma F, Mo Y. Metalloradical complex Co-C˙Ph3 catalyzes the CO 2 reduction in gas phase: a theoretical study. Phys Chem Chem Phys 2021; 23:1392-1400. [PMID: 33476353 DOI: 10.1039/d0cp04453a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Metal-stabilized radicals have been increasingly exploited in modern organic synthesis. Here, we theoretically designed a metalloradical complex Co-C˙Ph3 with the triplet characters through the transition metal cobalt (Co0) coordinating a triphenylmethyl radical. The potential catalytic role of this novel metalloradical in the CO2 reduction with H2/CH4 in the gas phase was explored via density functional theory (DFT) calculations. For the CO2 reduction reaction with H2, there are two possible pathways: one (path A) is the activation of CO2 by Co-C˙Ph3, followed by the hydrogenation of CO2. The other (path B) starts from the splitting of the H-H bond by Co-C˙Ph3, leading to the transition-metal hydride complex CoH-H, which can reduce CO2. DFT computations show that path B is more favorable than path A as their rate-determining free energy barriers are 18.3 and 27.2 kcal mol-1, respectively. However, for the reduction of CO2 by CH4 two different products, CH3COOH and HCOOCH3, can be generated following different reaction routes. Both routes begin with one CH4 molecule approaching the metalloradical Co-C˙Ph3 to form the intermediate CoH-CH3. This intermediate can evolve following two different pathways, depending on whether the H bonded to Co is transferred to the O (pathway PO) or the C (pathway PC) of CO2. Comparing their rate-determining steps, we identified that the PO route is more favorable for the reduction of CO2 by CH4 to CH3COOH with the reaction barrier 24.5 kcal mol-1. Thus, the present Co0-based metalloradical system represents a viable catalytic protocol that can contribute to the effective utilization of small molecules (H2 and CH4) to reduce CO2, and provides an alternative strategy for the exploration of CO2 conversion.
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Affiliation(s)
- Chuan-Kai Tang
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei, 235000, China.
| | - Ya-Zhou Li
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei, 235000, China.
| | - Zhong-Jun Zhou
- Institute of Theoretical Chemistry, Jilin University, Changchun, 130023, China
| | - Fang Ma
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei, 235000, China.
| | - Yirong Mo
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, NC 27401, USA.
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21
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Funk P, Richrath RB, Bohle F, Grimme S, Gansäuer A. Oxidation Under Reductive Conditions: From Benzylic Ethers to Acetals with Perfect Atom‐Economy by Titanocene(III) Catalysis. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202013561] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Pierre Funk
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Str. 1 53121 Bonn Germany
| | - Ruben B. Richrath
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Str. 1 53121 Bonn Germany
| | - Fabian Bohle
- Mulliken Center for Theoretical Chemistry Institut für Physikalische und Theoretische Chemie Universität Bonn Beringstraße 4 53115 Bonn Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry Institut für Physikalische und Theoretische Chemie Universität Bonn Beringstraße 4 53115 Bonn Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Str. 1 53121 Bonn Germany
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22
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Chatterjee B, Chang W, Werlé C. Molecularly Controlled Catalysis – Targeting Synergies Between Local and Non‐local Environments. ChemCatChem 2020. [DOI: 10.1002/cctc.202001431] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Basujit Chatterjee
- Max Planck Institute for Chemical Energy Conversion Stiftstr. 34–36 45470 Mülheim an der Ruhr Germany
- Ruhr University Bochum Universitätsstr. 150 44801 Bochum Germany
| | - Wei‐Chieh Chang
- Max Planck Institute for Chemical Energy Conversion Stiftstr. 34–36 45470 Mülheim an der Ruhr Germany
- Ruhr University Bochum Universitätsstr. 150 44801 Bochum Germany
| | - Christophe Werlé
- Max Planck Institute for Chemical Energy Conversion Stiftstr. 34–36 45470 Mülheim an der Ruhr Germany
- Ruhr University Bochum Universitätsstr. 150 44801 Bochum Germany
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23
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Yang M, Wang Y, Jian Y, Leng D, Zhang W, Zhang G, Sun H, Gao Z. A sustainable water-tolerant catalyst with enhanced Lewis acidity: Dual activation of Cp2TiCl2 via ligand and solvent. MOLECULAR CATALYSIS 2020. [DOI: 10.1016/j.mcat.2020.111247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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24
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Lang K, Li C, Kim I, Zhang XP. Enantioconvergent Amination of Racemic Tertiary C-H Bonds. J Am Chem Soc 2020; 142:20902-20911. [PMID: 33249845 DOI: 10.1021/jacs.0c11103] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Racemization is considered to be an intrinsic stereochemical feature of free radical chemistry as can be seen in traditional radical halogenation reactions of optically active tertiary C-H bonds. If the facile process of radical racemization could be effectively combined with an ensuing step of bond formation in an enantioselective fashion, then it would give rise to deracemizative functionalization of racemic tertiary C-H bonds for stereoselective construction of chiral molecules bearing quaternary stereocenters. As a demonstration of this unique potential in radical chemistry, we herein report that metalloradical catalysis can be successfully applied to devise Co(II)-based catalytic system for enantioconvergent radical amination of racemic tertiary C(sp3)-H bonds. The key to the success of the radical process is the development of Co(II)-based metalloradical catalyst with fitting steric, electronic, and chiral environments of the D2-symmetric chiral amidoporphyrin as the supporting ligand. The existence of optimal reaction temperature is recognized as an important factor in the realization of the enantioconvergent radical process. Supported by an optimized chiral ligand, the Co(II)-based metalloradical system can effectively catalyze the enantioconvergent 1,6-amination of racemic tertiary C(sp3)-H bonds at the optimal temperature, affording chiral α-tertiary amines in excellent yields with high enantiocontrol of the newly created quaternary stereocenters. Systematic studies, including experiments utilizing optically active deuterium-labeled C-H substrates as a model system, shed light on the underlying mechanistic details of this new catalytic process for enantioconvergent radical C-H amination. The remarkable power to create quaternary stereocenters bearing multiple functionalities from ubiquitous C-H bonds, as showcased with stereoselective construction of bicyclic N-heterocycles, opens the door for future synthetic applications of this new radical technology.
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Affiliation(s)
- Kai Lang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Chaoqun Li
- Department of Chemistry, University of South Florida, Tampa, Florida 33620, United States
| | - Isaac Kim
- 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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25
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Jin LM, Xu P, Xie J, Zhang XP. Enantioselective Intermolecular Radical C-H Amination. J Am Chem Soc 2020; 142:20828-20836. [PMID: 33238707 DOI: 10.1021/jacs.0c10415] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Radical reactions hold a number of inherent advantages in organic synthesis that may potentially impact the planning and practice for construction of organic molecules. However, the control of enantioselectivity in radical processes remains one of the longstanding challenges. While significant advances have recently been achieved in intramolecular radical reactions, the governing of asymmetric induction in intermolecular radical reactions still poses challenging issues. We herein report a catalytic approach that is highly effective for controlling enantioselectivity as well as reactivity of the intermolecular radical C-H amination of carboxylic acid esters with organic azides via Co(II)-based metalloradical catalysis (MRC). The key to the success lies in the catalyst development to maximize noncovalent attractive interactions through fine-tuning of the remote substituents of the D2-symmetric chiral amidoporphyrin ligand. This noncovalent interaction strategy presents a solution that may be generally applicable in controlling reactivity and enantioselectivity in intermolecular radical reactions. The Co(II)-catalyzed intermolecular C-H amination, which operates under mild conditions with the C-H substrate as the limiting reagent, exhibits a broad substrate scope with high chemoselectivity, providing effective access to valuable chiral amino acid derivatives with high enantioselectivities. Systematic mechanistic studies shed light into the working details of the underlying stepwise radical pathway for the Co(II)-based C-H amination.
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Affiliation(s)
- Li-Mei Jin
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Pan Xu
- 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
| | - X Peter Zhang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
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26
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Fermi A, Gualandi A, Bergamini G, Cozzi PG. Shining Light on Ti
IV
Complexes: Exceptional Tools for Metallaphotoredox Catalysis. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000966] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Andrea Fermi
- Dipartimento di Chimica "G. Ciamician" Università di Bologna via Selmi 2 40126 Bologna Italy
| | - Andrea Gualandi
- Dipartimento di Chimica "G. Ciamician" Università di Bologna via Selmi 2 40126 Bologna Italy
| | - Giacomo Bergamini
- Dipartimento di Chimica "G. Ciamician" Università di Bologna via Selmi 2 40126 Bologna Italy
| | - Pier Giorgio Cozzi
- Dipartimento di Chimica "G. Ciamician" Università di Bologna via Selmi 2 40126 Bologna Italy
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27
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Zhang Z, Hilche T, Slak D, Rietdijk NR, Oloyede UN, Flowers RA, Gansäuer A. Titanocenes as Photoredox Catalysts Using Green-Light Irradiation. Angew Chem Int Ed Engl 2020; 59:9355-9359. [PMID: 32216162 PMCID: PMC7317808 DOI: 10.1002/anie.202001508] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/08/2020] [Indexed: 11/16/2022]
Abstract
Irradiation of Cp2 TiCl2 with green light leads to electronically excited [Cp2 TiCl2 ]*. This complex constitutes an efficient photoredox catalyst for the reduction of epoxides and for 5-exo cyclizations of suitably unsaturated epoxides. To the best of our knowledge, our system is the first example of a molecular titanium photoredox catalyst.
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Affiliation(s)
- Zhenhua Zhang
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Tobias Hilche
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Daniel Slak
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Niels R. Rietdijk
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | | | | | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
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28
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Zhang Z, Hilche T, Slak D, Rietdijk NR, Oloyede UN, Flowers RA, Gansäuer A. Titanocenes as Photoredox Catalysts Using Green‐Light Irradiation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202001508] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Zhenhua Zhang
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Tobias Hilche
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Daniel Slak
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Niels R. Rietdijk
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | | | | | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
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29
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Manßen M, Schafer LL. Titanium catalysis for the synthesis of fine chemicals – development and trends. Chem Soc Rev 2020; 49:6947-6994. [DOI: 10.1039/d0cs00229a] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Atlas as a Titan(ium) is holding the earth-abundant chemistry world. Titanium is the second most abundant transition metal, is a key player in important industrial processes (e.g. polyethylene) and shows much promise for diverse applications in the future.
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Affiliation(s)
- Manfred Manßen
- The Department of Chemistry
- The University of British Columbia
- Vancouver
- Canada
| | - Laurel L. Schafer
- The Department of Chemistry
- The University of British Columbia
- Vancouver
- Canada
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30
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Tian S, Lv S, Jia X, Ma L, Li B, Zhang G, Gao W, Wei Y, Chen J. CV‐driven Optimization: Cobalt‐Catalyzed Electrochemical Expedient Oxychlorination of Alkenes via ORR. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201901260] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Siyu Tian
- Shandong Provincial Key Laboratory of Molecular EngineeringState Key Laboratory of Biobased Material and Green PapermakingSchool of Chemistry and Pharmaceutical Engineering Qilu University of Technology (Shandong Academy of Sciences) Jinan 250353 People's Republic of China
| | - Shide Lv
- Shandong Provincial Key Laboratory of Molecular EngineeringState Key Laboratory of Biobased Material and Green PapermakingSchool of Chemistry and Pharmaceutical Engineering Qilu University of Technology (Shandong Academy of Sciences) Jinan 250353 People's Republic of China
| | - Xiaofei Jia
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOECollege of Chemistry and Molecular Engineering. Qingdao University of Science and Technology Qingdao 266042 People's Republic of China
| | - Li Ma
- Shandong Provincial Key Laboratory of Molecular EngineeringState Key Laboratory of Biobased Material and Green PapermakingSchool of Chemistry and Pharmaceutical Engineering Qilu University of Technology (Shandong Academy of Sciences) Jinan 250353 People's Republic of China
| | - Baoying Li
- Shandong Provincial Key Laboratory of Molecular EngineeringState Key Laboratory of Biobased Material and Green PapermakingSchool of Chemistry and Pharmaceutical Engineering Qilu University of Technology (Shandong Academy of Sciences) Jinan 250353 People's Republic of China
| | - Guofeng Zhang
- Shandong Provincial Key Laboratory of Molecular EngineeringState Key Laboratory of Biobased Material and Green PapermakingSchool of Chemistry and Pharmaceutical Engineering Qilu University of Technology (Shandong Academy of Sciences) Jinan 250353 People's Republic of China
| | - Wei Gao
- Shandong Provincial Key Laboratory of Molecular EngineeringState Key Laboratory of Biobased Material and Green PapermakingSchool of Chemistry and Pharmaceutical Engineering Qilu University of Technology (Shandong Academy of Sciences) Jinan 250353 People's Republic of China
| | - Yingqin Wei
- Shandong Provincial Key Laboratory of Molecular EngineeringState Key Laboratory of Biobased Material and Green PapermakingSchool of Chemistry and Pharmaceutical Engineering Qilu University of Technology (Shandong Academy of Sciences) Jinan 250353 People's Republic of China
| | - Jianbin Chen
- Shandong Provincial Key Laboratory of Molecular EngineeringState Key Laboratory of Biobased Material and Green PapermakingSchool of Chemistry and Pharmaceutical Engineering Qilu University of Technology (Shandong Academy of Sciences) Jinan 250353 People's Republic of China
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31
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Hu Y, Lang K, Li C, Gill JB, Kim I, Lu H, Fields KB, Marshall M, Cheng Q, Cui X, Wojtas L, Zhang XP. Enantioselective Radical Construction of 5-Membered Cyclic Sulfonamides by Metalloradical C-H Amination. J Am Chem Soc 2019; 141:18160-18169. [PMID: 31622088 DOI: 10.1021/jacs.9b08894] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Both arylsulfonyl and alkylsulfonyl azides can be effectively activated by the cobalt(II) complexes of D2-symmetric chiral amidoporphyrins for enantioselective radical 1,5-C-H amination to stereoselectively construct 5-membered cyclic sulfonamides. In addition to C-H bonds with varied electronic properties, the Co(II)-based metalloradical system features chemoselective amination of allylic C-H bonds and is compatible with heteroaryl groups, producing functionalized 5-membered chiral cyclic sulfonamides in high yields with high enantioselectivities. The unique profile of reactivity and selectivity of the Co(II)-catalyzed C-H amination is attributed to its underlying stepwise radical mechanism, which is supported by several lines of experimental evidence.
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Affiliation(s)
- Yang Hu
- Department of Chemistry , University of South Florida , Tampa , Florida 33620-5250 , United States
| | - Kai Lang
- Department of Chemistry, Merkert Chemistry Center , Boston College , Chestnut Hill , Massachusetts 02467 , United States
| | - Chaoqun Li
- Department of Chemistry , University of South Florida , Tampa , Florida 33620-5250 , United States
| | - Joseph B Gill
- Department of Chemistry , University of South Florida , Tampa , Florida 33620-5250 , United States
| | - Isaac Kim
- Department of Chemistry, Merkert Chemistry Center , Boston College , Chestnut Hill , Massachusetts 02467 , United States
| | - Hongjian Lu
- Department of Chemistry , University of South Florida , Tampa , Florida 33620-5250 , United States
| | - Kimberly B Fields
- Department of Chemistry , University of South Florida , Tampa , Florida 33620-5250 , United States
| | - McKenzie Marshall
- Department of Chemistry , University of South Florida , Tampa , Florida 33620-5250 , United States
| | - Qigan Cheng
- Department of Chemistry , University of South Florida , Tampa , Florida 33620-5250 , United States
| | - Xin Cui
- Department of Chemistry , University of South Florida , Tampa , Florida 33620-5250 , United States
| | - Lukasz Wojtas
- Department of Chemistry , University of South Florida , Tampa , Florida 33620-5250 , United States
| | - X Peter Zhang
- Department of Chemistry, Merkert Chemistry Center , Boston College , Chestnut Hill , Massachusetts 02467 , United States
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32
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Abstract
New catalytic strategies that leverage single-electron redox events have provided chemists with useful tools for solving synthetic problems. In this context, Ti offers opportunities that are complementary to late transition metals for reaction discovery. Following foundational work on epoxide reductive functionalization, recent methodological advances have significantly expanded the repertoire of Ti radical chemistry. This Synopsis summarizes recent developments in the burgeoning area of Ti radical catalysis with a focus on innovative catalytic strategies such as radical redox-relay and dual catalysis.
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Affiliation(s)
- Terry McCallum
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
| | - Xiangyu Wu
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
| | - Song Lin
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
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33
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Mühlhaus F, Weißbarth H, Dahmen T, Schnakenburg G, Gansäuer A. Merging Regiodivergent Catalysis with Atom-Economical Radical Arylation. Angew Chem Int Ed Engl 2019; 58:14208-14212. [PMID: 31394024 PMCID: PMC6852184 DOI: 10.1002/anie.201908860] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Indexed: 12/11/2022]
Abstract
A titanocene-catalyzed regiodivergent radical arylation is described that allows access to either enantiomerically pure tetrahydroquinolines or indolines from a common starting material. The regioselectivity of epoxide opening that results in the high selectivity of heterocycle formation is controlled by two factors, the absolute configuration of the enantiopure ligands of the (C5 H4 R)2 TiX2 catalyst and the inorganic ligand X (X=Cl, OTs). The overall reaction is atom-economical and constitutes a radical Friedel-Crafts alkylation.
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Affiliation(s)
- Felix Mühlhaus
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Hendrik Weißbarth
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Tobias Dahmen
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Gregor Schnakenburg
- Institut für Anorganische ChemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Straße 153121BonnGermany
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34
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Mühlhaus F, Weißbarth H, Dahmen T, Schnakenburg G, Gansäuer A. Merging Regiodivergent Catalysis with Atom‐Economical Radical Arylation. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201908860] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Felix Mühlhaus
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Hendrik Weißbarth
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Tobias Dahmen
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Gregor Schnakenburg
- Institut für Anorganische Chemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Straße 1 53121 Bonn Germany
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35
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Liedtke T, Hilche T, Klare S, Gansäuer A. Condition Screening for Sustainable Catalysis in Single-Electron Steps by Cyclic Voltammetry: Additives and Solvents. CHEMSUSCHEM 2019; 12:3166-3171. [PMID: 30779429 DOI: 10.1002/cssc.201900344] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 02/18/2019] [Indexed: 06/09/2023]
Abstract
Cyclic voltammetry-based screening method for Cp2 TiX-catalyzed reactions is extended to the screening of solvents other than tetrahydrofuran for bulk electrolysis of the catalyst and radical arylation. It was found that CH3 CN can be used as a solvent for both processes without additives. Furthermore, in tetrahydrofuran, squaramide L2 is more efficient than the previously reported supramolecular halide binder, Schreiner's thiourea L1. The results extend the usefulness of the proposed time and resource-efficient screening method for designing catalysis reactions in single-electron steps.
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Affiliation(s)
- Theresa Liedtke
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Tobias Hilche
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Sven Klare
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
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36
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Ye KY, McCallum T, Lin S. Bimetallic Radical Redox-Relay Catalysis for the Isomerization of Epoxides to Allylic Alcohols. J Am Chem Soc 2019; 141:9548-9554. [PMID: 31180216 DOI: 10.1021/jacs.9b04993] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Organic radicals are generally short-lived intermediates with exceptionally high reactivity. Strategically, achieving synthetically useful transformations mediated by organic radicals requires both efficient initiation and selective termination events. Here, we report a new catalytic strategy, namely, bimetallic radical redox-relay, in the regio- and stereoselective rearrangement of epoxides to allylic alcohols. This approach exploits the rich redox chemistry of Ti and Co complexes and merges reductive epoxide ring opening (initiation) with hydrogen atom transfer (termination). Critically, upon effecting key bond-forming and -breaking events, Ti and Co catalysts undergo proton transfer/electron transfer with one another to achieve turnover, thus constituting a truly synergistic dual catalytic system.
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Affiliation(s)
- Ke-Yin Ye
- College of Chemistry , Fuzhou University , Fuzhou , 350116 , P.R. China.,Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
| | - Terry McCallum
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
| | - Song Lin
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
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37
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Lankelma M, Olivares AM, de Bruin B. [Co(TPP)]-Catalyzed Formation of Substituted Piperidines. Chemistry 2019; 25:5658-5663. [PMID: 30844097 PMCID: PMC6563703 DOI: 10.1002/chem.201900587] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Indexed: 01/12/2023]
Abstract
Radical cyclization via cobalt(III)-carbene radical intermediates is a powerful method for the synthesis of (hetero)cyclic structures. Building on the recently reported synthesis of five-membered N-heterocyclic pyrrolidines catalyzed by CoII porphyrins, the [Co(TPP)]-catalyzed formation of useful six-membered N-heterocyclic piperidines directly from linear aldehydes is presented herein. The piperidines were obtained in overall high yields, with linear alkenes being formed as side products in small amounts. A DFT study was performed to gain a deeper mechanistic understanding of the cobalt(II)-porphyrin-catalyzed formation of pyrrolidines, piperidines, and linear alkenes. The calculations showed that the alkenes are unlikely to be formed through an expected 1,2-hydrogen-atom transfer to the carbene carbon. Instead, the calculations were consistent with a pathway involving benzyl-radical formation followed by radical-rebound ring closure to form the piperidines. Competitive 1,5-hydrogen-atom transfer from the β-position to the benzyl radical explained the formation of linear alkenes as side products.
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Affiliation(s)
- Marianne Lankelma
- Van 't Hoff Institute for Molecular Sciences (HIMS)Homogeneous, Supramolecular & Bio-Inspired CatalysisUniversity of AmsterdamScience Park 9041098 XHAmsterdamThe Netherlands
| | - Astrid M. Olivares
- Department of ChemistryUniversity of Rochester404 Hutchison HallRochesterNY14627-0216USA
| | - Bas de Bruin
- Van 't Hoff Institute for Molecular Sciences (HIMS)Homogeneous, Supramolecular & Bio-Inspired CatalysisUniversity of AmsterdamScience Park 9041098 XHAmsterdamThe Netherlands
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38
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Zhang Z, Richrath RB, Gansäuer A. Merging Catalysis in Single Electron Steps with Photoredox Catalysis—Efficient and Sustainable Radical Chemistry. ACS Catal 2019. [DOI: 10.1021/acscatal.9b00787] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Zhenhua Zhang
- Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Ruben B. Richrath
- Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
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39
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van der Vlugt JI. Radical-Type Reactivity and Catalysis by Single-Electron Transfer to or from Redox-Active Ligands. Chemistry 2019; 25:2651-2662. [PMID: 30084211 PMCID: PMC6471147 DOI: 10.1002/chem.201802606] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Indexed: 12/12/2022]
Abstract
Controlled ligand-based redox-activity and chemical non-innocence are rapidly gaining importance for selective (catalytic) processes. This Concept aims to provide an overview of the progress regarding ligand-to-substrate single-electron transfer as a relatively new mode of operation to exploit ligand-centered reactivity and catalysis based thereon.
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Affiliation(s)
- Jarl Ivar van der Vlugt
- Bio-Inspired Homogeneous and Supramolecular Catalysis Groupvan ‘t Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098 XHAmsterdamNetherlands
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40
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Beaumier EP, Pearce AJ, See XY, Tonks IA. Modern applications of low-valent early transition metals in synthesis and catalysis. Nat Rev Chem 2019; 3:15-34. [PMID: 30989127 PMCID: PMC6462221 DOI: 10.1038/s41570-018-0059-x] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Low-valent early transition metals are often intrinsically highly reactive as a result of their strong propensity toward oxidation to more stable high-valent states. Harnessing these highly reducing complexes for productive reactivity is potentially powerful for C-C bond construction, organic reductions, small-molecule activation and many other reactions that offer orthogonal chemoselectivity and/or regioselectivity patterns to processes promoted by late transition metals. Recent years have seen many exciting new applications of low-valent metals through building new catalytic and/or multicomponent reaction manifolds out of classical reactivity patterns. In this Review, we survey new methods that employ early transition metals and invoke low-valent precursors or intermediates in order to identify common themes and strategies in synthesis and catalysis.
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Affiliation(s)
- Evan P. Beaumier
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Adam J. Pearce
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Xin Yi See
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Ian A. Tonks
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
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41
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Li N, Yao J, Wang L, Wei J, Liu W, Liu W, Xu X, Liang Z. Titanocene perfluorobutanesulfonate catalyzed reduction of disulfides in the presence of zinc to synthesize unsymmetrical sulfides. INORG CHEM COMMUN 2018. [DOI: 10.1016/j.inoche.2018.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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42
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Wu X, Hao W, Ye KY, Jiang B, Pombar G, Song Z, Lin S. Ti-Catalyzed Radical Alkylation of Secondary and Tertiary Alkyl Chlorides Using Michael Acceptors. J Am Chem Soc 2018; 140:14836-14843. [PMID: 30303379 PMCID: PMC6530901 DOI: 10.1021/jacs.8b08605] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Alkyl chlorides are common functional groups in synthetic organic chemistry. However, the engagement of unactivated alkyl chlorides, especially tertiary alkyl chlorides, in transition-metal-catalyzed C-C bond formation remains challenging. Herein, we describe the development of a TiIII-catalyzed radical addition of 2° and 3° alkyl chlorides to electron-deficient alkenes. Mechanistic data are consistent with inner-sphere activation of the C-Cl bond featuring TiIII-mediated Cl atom abstraction. Evidence suggests that the active TiIII catalyst is generated from the TiIV precursor in a Lewis-acid-assisted electron transfer process.
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Affiliation(s)
- Xiangyu Wu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | | | - Ke-Yin Ye
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Binyang Jiang
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Gisselle Pombar
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Zhidong Song
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Song Lin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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43
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Streuff J, Himmel D, Younas SL. Understanding titanium-catalysed radical-radical reactions: a DFT study unravels the complex kinetics of ketone-nitrile couplings. Dalton Trans 2018; 47:5072-5082. [PMID: 29561012 DOI: 10.1039/c8dt00643a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The computational investigation of a titanium-catalysed reductive radical-radical coupling is reported. The results match the conclusions from an earlier experimental study and enable a further interpretation of the previously observed complex reaction kinetics. Furthermore, the interplay between neutral and cationic reaction pathways in titanium(iii)-catalysed reactions is investigated for the first time. The results show that hydrochloride additives and reaction byproducts play an important role in the respective equilibria. A full reaction profile is assembled and the computed activation barrier is found to be in reasonable agreement with the experiment. The conclusions are of fundamental importance to the field of low-valent titanium catalysis and the understanding of related catalytic radical-radical coupling reactions.
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Affiliation(s)
- Jan Streuff
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany.
| | - Daniel Himmel
- Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany
| | - Sara L Younas
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany.
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44
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Liedtke T, Spannring P, Riccardi L, Gansäuer A. Mechanism-Based Condition Screening for Sustainable Catalysis in Single-Electron Steps by Cyclic Voltammetry. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201800731] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Theresa Liedtke
- Kekulé-Institut für Organische Chemie und Biochemie; Universität Bonn; Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Peter Spannring
- Kekulé-Institut für Organische Chemie und Biochemie; Universität Bonn; Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Ludovico Riccardi
- Kekulé-Institut für Organische Chemie und Biochemie; Universität Bonn; Gerhard Domagk-Straße 1 53121 Bonn Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie; Universität Bonn; Gerhard Domagk-Straße 1 53121 Bonn Germany
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45
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Liedtke T, Spannring P, Riccardi L, Gansäuer A. Mechanism-Based Condition Screening for Sustainable Catalysis in Single-Electron Steps by Cyclic Voltammetry. Angew Chem Int Ed Engl 2018; 57:5006-5010. [PMID: 29488673 DOI: 10.1002/anie.201800731] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 02/22/2018] [Indexed: 12/16/2022]
Abstract
A cyclic-voltammetry-based screening method for Cp2 TiX-catalyzed reactions is introduced. Our mechanism-based approach enables the study of the influence of various additives on the electrochemically generated active catalyst Cp2 TiX, which is in equilibrium with catalytically inactive [Cp2 TiX2 ]- . Thioureas and ureas are most efficient in the generation of Cp2 TiX in THF. Knowing the precise position of the equilibrium between Cp2 TiX and [Cp2 TiX2 ]- allowed us to identify reaction conditions for the bulk electrolysis of Cp2 TiX2 complexes and for Cp2 TiX-catayzed radical arylations without having to carry out the reactions. Our time- and resource-efficient approach is of general interest for the design of catalytic reactions that proceed in single-electron steps.
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Affiliation(s)
- Theresa Liedtke
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Straße 1, 53121, Bonn, Germany
| | - Peter Spannring
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Straße 1, 53121, Bonn, Germany
| | - Ludovico Riccardi
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Straße 1, 53121, Bonn, Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Straße 1, 53121, Bonn, Germany
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46
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Richrath RB, Olyschläger T, Hildebrandt S, Enny DG, Fianu GD, Flowers RA, Gansäuer A. Cp 2 TiX Complexes for Sustainable Catalysis in Single-Electron Steps. Chemistry 2018; 24:6371-6379. [PMID: 29327511 DOI: 10.1002/chem.201705707] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Indexed: 12/18/2022]
Abstract
We present a combined electrochemical, kinetic, and synthetic study with a novel and easily accessible class of titanocene catalysts for catalysis in single-electron steps. The tailoring of the electronic properties of our Cp2 TiX-catalysts that are prepared in situ from readily available Cp2 TiX2 is achieved by varying the anionic ligand X. Of the complexes investigated, Cp2 TiOMs proved to be either equal or substantially superior to the best catalysts developed earlier. The kinetic and thermodynamic properties pertinent to catalysis have been determined. They allow a mechanistic understanding of the subtle interplay of properties required for an efficient oxidative addition and reduction. Therefore, our study highlights that efficient catalysts do not require the elaborate covalent modification of the cyclopentadienyl ligands.
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Affiliation(s)
- Ruben B Richrath
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Str. 1, 53121, Bonn, Germany
| | - Theresa Olyschläger
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Str. 1, 53121, Bonn, Germany
| | - Sven Hildebrandt
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Str. 1, 53121, Bonn, Germany
| | - Daniel G Enny
- Department of Chemistry, Lehigh University, Bethlehem, PA, 18015, USA
| | - Godfred D Fianu
- Department of Chemistry, Lehigh University, Bethlehem, PA, 18015, USA
| | - Robert A Flowers
- Department of Chemistry, Lehigh University, Bethlehem, PA, 18015, USA
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard Domagk-Str. 1, 53121, Bonn, Germany
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47
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te Grotenhuis C, van den Heuvel N, van der Vlugt JI, de Bruin B. Catalytic Dibenzocyclooctene Synthesis via Cobalt(III)-Carbene Radical and ortho-Quinodimethane Intermediates. Angew Chem Int Ed Engl 2018; 57:140-145. [PMID: 29155465 PMCID: PMC5767734 DOI: 10.1002/anie.201711028] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Indexed: 12/02/2022]
Abstract
The metalloradical activation of ortho-benzallylaryl N-tosyl hydrazones with [Co(TPP)] (TPP=tetraphenylporphyrin) as the catalyst enabled the controlled exploitation of the single-electron reactivity of the redox non-innocent carbene intermediate. This method offers a novel route to prepare eight-membered rings, using base metal catalysis to construct a series of unique dibenzocyclooctenes through selective Ccarbene -Caryl cyclization. The desired eight-membered-ring products were obtained in good to excellent yields. A large variety of aromatic substituents are tolerated. The proposed reaction mechanism involves intramolecular hydrogen atom transfer (HAT) to CoIII -carbene radical intermediates followed by dissociation of an ortho-quinodimethane that undergoes 8π cyclization. The mechanism is supported by DFT calculations, and the presence of radical-type intermediates was confirmed by trapping experiments.
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Affiliation(s)
- Colet te Grotenhuis
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) group Van't Hoff Institute for Molecular Sciences (HIMS)University of AmsterdamScience Park 9041098XHAmsterdamThe Netherlands
| | - Naudin van den Heuvel
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) group Van't Hoff Institute for Molecular Sciences (HIMS)University of AmsterdamScience Park 9041098XHAmsterdamThe Netherlands
| | - Jarl Ivar van der Vlugt
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) group Van't Hoff Institute for Molecular Sciences (HIMS)University of AmsterdamScience Park 9041098XHAmsterdamThe Netherlands
| | - Bas de Bruin
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) group Van't Hoff Institute for Molecular Sciences (HIMS)University of AmsterdamScience Park 9041098XHAmsterdamThe Netherlands
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48
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van Leest NP, Epping RF, van Vliet KM, Lankelma M, van den Heuvel EJ, Heijtbrink N, Broersen R, de Bruin B. Single-Electron Elementary Steps in Homogeneous Organometallic Catalysis. ADVANCES IN ORGANOMETALLIC CHEMISTRY 2018. [DOI: 10.1016/bs.adomc.2018.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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49
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Yeung D, Penafiel J, Zijlstra HS, McIndoe JS. Oxidation of Titanocene(III): The Deceptive Simplicity of a Color Change. Inorg Chem 2017; 57:457-461. [DOI: 10.1021/acs.inorgchem.7b02705] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Darien Yeung
- Department of Chemistry, University of Victoria, PO Box 1700
STN CSC, Victoria, BC V8W 2Y2, Canada
| | - Johanne Penafiel
- Department of Chemistry, University of Victoria, PO Box 1700
STN CSC, Victoria, BC V8W 2Y2, Canada
| | - Harmen S. Zijlstra
- Department of Chemistry, University of Victoria, PO Box 1700
STN CSC, Victoria, BC V8W 2Y2, Canada
| | - J. Scott McIndoe
- Department of Chemistry, University of Victoria, PO Box 1700
STN CSC, Victoria, BC V8W 2Y2, Canada
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50
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te Grotenhuis C, van den Heuvel N, van der Vlugt JI, de Bruin B. Catalytic Dibenzocyclooctene Synthesis via Cobalt(III)-Carbene Radical and ortho
-Quinodimethane Intermediates. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201711028] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Colet te Grotenhuis
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) group Van't Hoff Institute for Molecular Sciences (HIMS); University of Amsterdam; Science Park 904 1098 XH Amsterdam The Netherlands
| | - Naudin van den Heuvel
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) group Van't Hoff Institute for Molecular Sciences (HIMS); University of Amsterdam; Science Park 904 1098 XH Amsterdam The Netherlands
| | - Jarl Ivar van der Vlugt
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) group Van't Hoff Institute for Molecular Sciences (HIMS); University of Amsterdam; Science Park 904 1098 XH Amsterdam The Netherlands
| | - Bas de Bruin
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) group Van't Hoff Institute for Molecular Sciences (HIMS); University of Amsterdam; Science Park 904 1098 XH Amsterdam The Netherlands
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