1
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Gary S, Woolley J, Goia S, Bloom S. Unlocking flavin photoacid catalysis through electrophotochemistry. Chem Sci 2024; 15:11444-11454. [PMID: 39055006 PMCID: PMC11268482 DOI: 10.1039/d4sc03054k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Accepted: 06/17/2024] [Indexed: 07/27/2024] Open
Abstract
Molecular flavins are one of the most versatile photocatalysts. They can coordinate single and multiple electron transfer processes, gift hydrogen atoms, form reversible covalent linkages that support group transfer mechanisms, and impart photonic energy to ground state molecules, priming them for downstream reactions. But one mechanism that has not featured extensively is the ability of flavins to act as photoacids. Herein, we disclose our proof-of-concept studies showing that electrophotochemistry can transform fully oxidized flavin quinones to super-oxidized flavinium photoacids that successfully guide proton-transfer and deliver acid-catalyzed products. We also show that these species can adopt a second mechanism wherein they react with water to release hydroxyl radicals that facilitate hydrogen-atom abstraction and sp3C-H functionalization protocols. Together, this unprecedented bimodal reactivity enables electro-generated flavinium salts to affect synthetic chemistries previously unknown to flavins, greatly expanding their versatility as catalysts.
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Affiliation(s)
- Samuel Gary
- Department of Medicinal Chemistry, University of Kansas Lawrence 66045 USA
| | - Jack Woolley
- Department of Physics, University of Warwick Coventry CV4 7AL UK
| | - Sofia Goia
- Forensic Centre for Digital Scanning and 3D Printing, WMG, University of Warwick Coventry CV4 7AL UK
| | - Steven Bloom
- Department of Medicinal Chemistry, University of Kansas Lawrence 66045 USA
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2
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Brunard E, Boquet V, Saget T, Sosa Carrizo ED, Sircoglou M, Dauban P. Catalyst-Controlled Intermolecular Homobenzylic C(sp 3)-H Amination for the Synthesis of β-Arylethylamines. J Am Chem Soc 2024; 146:5843-5854. [PMID: 38387076 DOI: 10.1021/jacs.3c10964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
The combination of a tailored sulfamate with a C4-symmetrical rhodium(II) tetracarboxylate allows to uncover a selective intermolecular amination of unactivated homobenzylic C(sp3)-H bonds. The reaction has a broad scope (>30 examples) and proceeds with a high level of regioselectivity with homobenzylic/benzylic ratio of up to 35:1, thereby providing a direct access to β-arylethylamines that are of utmost interest in medicinal chemistry. Computational investigations evidenced a concerted mechanism, involving an asynchronous transition state. Based on a combined activation strain model and energy decomposition analysis, the regioselectivity of the reaction was found to rely mainly on the degree of orbital interaction between the [Rh2]-nitrene and the C-H bond. The latter is facilitated at the homobenzylic position due to the establishment of specific noncovalent interactions within the catalytic pocket.
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Affiliation(s)
- Erwan Brunard
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France
| | - Vincent Boquet
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France
| | - Tanguy Saget
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France
| | - E Daiann Sosa Carrizo
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay, 91400 Orsay, France
| | - Marie Sircoglou
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay, 91400 Orsay, France
| | - Philippe Dauban
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France
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3
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Keum H, Ryoo H, Kim D, Chang S. Amidative β-Scission of Alcohols Enabled by Dual Catalysis of Photoredox Proton-Coupled Electron Transfer and Inner-Sphere Ni-Nitrenoid Transfer. J Am Chem Soc 2024; 146:1001-1008. [PMID: 38109265 DOI: 10.1021/jacs.3c11813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
The photoredox/Ni dual catalysis is an appealing strategy to enable unconventional C-heteroatom bond formation. While significant advances have been achieved using this system, intermolecular C(sp3)-N bond formation has been relatively underdeveloped due to the difficulty in C(sp3)-N reductive elimination. Herein, we present a new mechanistic approach that utilizes dioxazolones as the Ni(II)-nitrenoid precursor to capture carbon-centered radicals by merging proton-coupled electron transfer (PCET) with nickel catalysis, thus forming synthetically versatile N-alkyl amides using alcohols. Based on mechanistic investigations, the involvement of (κ2-N,O)Ni(II)-nitrenoid species was proposed to capture photoredox PCET-induced alkyl radicals, thereby playing a pivotal role to enable the C(sp3)-N bond formation.
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Affiliation(s)
- Hyeyun Keum
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea
| | - Harin Ryoo
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea
| | - Dongwook Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea
| | - Sukbok Chang
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea
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4
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Demidov N, Grebogi M, Bourne C, McKay AP, Cordes DB, Stasch A. A Convenient One-Pot Synthesis of a Sterically Demanding Aniline from Aryllithium Using Trimethylsilyl Azide, Conversion to β-Diketimines and Synthesis of a β-Diketiminate Magnesium Hydride Complex. Molecules 2023; 28:7569. [PMID: 38005290 PMCID: PMC10673297 DOI: 10.3390/molecules28227569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023] Open
Abstract
This work reports the one-pot synthesis of sterically demanding aniline derivatives from aryllithium species utilising trimethylsilyl azide to introduce amine functionalities and conversions to new examples of a common N,N'-chelating ligand system. The reaction of TripLi (Trip = 2,4,6-iPr3-C6H2) with trimethylsilyl azide afforded the silyltriazene TripN2N(SiMe3)2 in situ, which readily reacts with methanol under dinitrogen elimination to the aniline TripNH2 in good yield. The reaction pathways and by-products of the system have been studied. The extension of this reaction to a much more sterically demanding terphenyl system suggested that TerLi (Ter = 2,6-Trip2-C6H3) slowly reacted with trimethylsilyl azide to form a silyl(terphenyl)triazenide lithium complex in situ, predominantly underwent nitrogen loss to TerN(SiMe3)Li in parallel, which afforded TerN(SiMe3)H after workup, and can be deprotected under acidic conditions to form the aniline TerNH2. TripNH2 was furthermore converted to the sterically demanding β-diketimines RTripnacnacH (=HC{RCN(Trip)}2H), with R = Me, Et and iPr, in one-pot procedures from the corresponding 1,3-diketones. The bulkiest proligand was employed to synthesise the magnesium hydride complex [{(iPrTripnacnac)MgH}2], which shows a distorted dimeric structure caused by the substituents of the sterically demanding ligand moieties.
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Affiliation(s)
| | | | | | | | | | - Andreas Stasch
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK; (N.D.); (M.G.); (C.B.); (A.P.M.); (D.B.C.)
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5
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Yadav V, Wen L, Yadav S, Siegler MA, Goldberg DP. Selective Radical Transfer in a Series of Nonheme Iron(III) Complexes. Inorg Chem 2023; 62:17830-17842. [PMID: 37857315 PMCID: PMC11296666 DOI: 10.1021/acs.inorgchem.3c02617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
A series of nonheme iron complexes, FeIII(BNPAPh2O)(Lax)(Leq) (Lax/eq = N3-, NCS-, NCO-, and Cl-) have been synthesized using the previously reported BNPAPh2O- ligand. The ferrous analogs FeII(BNPAPh2O)(Lax) (Lax = N3-, NCS-, and NCO-) were also prepared. The complexes were structurally characterized using single crystal X-ray diffraction, which shows that all the FeIII complexes are six-coordinate, with one anionic ligand (Lax) in the H-bonding axial site and the other anionic ligand (Leq) in the equatorial plane, cis to the Lax ligand. The reaction of FeIII(BNPAPh2O-)(Lax)(Leq) with Ph3C• shows that one ligand is selectively transferred in each case. A selectivity trend emerges that shows •N3 is the most favored for transfer in each case to the carbon radical, whereas Cl• is the least favored. The NCO and NCS ligands showed an intermediate propensity for radical transfer, with NCS > NCO. The overall order of selectivity is N3 > NCS > NCO > Cl. In addition, we also demonstrated that H-bonding has a small effect on governing product selectivity by using a non-H-bonded ligand (DPAPh2O-). This study demonstrates the inherent radical transfer selectivity of nonhydroxo-ligated nonheme iron(III) complexes, which could be useful for efforts in synthetic and (bio)catalytic C-H functionalization.
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Affiliation(s)
- Vishal Yadav
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Lyupeng Wen
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Sudha Yadav
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Maxime A Siegler
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - David P Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
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6
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Carsch KM, North SC, DiMucci IM, Iliescu A, Vojáčková P, Khazanov T, Zheng SL, Cundari TR, Lancaster KM, Betley TA. Nitrene transfer from a sterically confined copper nitrenoid dipyrrin complex. Chem Sci 2023; 14:10847-10860. [PMID: 37829016 PMCID: PMC10566472 DOI: 10.1039/d3sc03641c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 09/04/2023] [Indexed: 10/14/2023] Open
Abstract
Despite the myriad Cu-catalyzed nitrene transfer methodologies to form new C-N bonds (e.g., amination, aziridination), the critical reaction intermediates have largely eluded direct characterization due to their inherent reactivity. Herein, we report the synthesis of dipyrrin-supported Cu nitrenoid adducts, investigate their spectroscopic features, and probe their nitrene transfer chemistry through detailed mechanistic analyses. Treatment of the dipyrrin CuI complexes with substituted organoazides affords terminally ligated organoazide adducts with minimal activation of the azide unit as evidenced by vibrational spectroscopy and single crystal X-ray diffraction. The Cu nitrenoid, with an electronic structure most consistent with a triplet nitrene adduct of CuI, is accessed following geometric rearrangement of the azide adduct from κ1-N terminal ligation to κ1-N internal ligation with subsequent expulsion of N2. For perfluorinated arylazides, stoichiometric and catalytic C-H amination and aziridination was observed. Mechanistic analysis employing substrate competition reveals an enthalpically-controlled, electrophilic nitrene transfer for primary and secondary C-H bonds. Kinetic analyses for catalytic amination using tetrahydrofuran as a model substrate reveal pseudo-first order kinetics under relevant amination conditions with a first-order dependence on both Cu and organoazide. Activation parameters determined from Eyring analysis (ΔH‡ = 9.2(2) kcal mol-1, ΔS‡ = -42(2) cal mol-1 K-1, ΔG‡298K = 21.7(2) kcal mol-1) and parallel kinetic isotope effect measurements (1.10(2)) are consistent with rate-limiting Cu nitrenoid formation, followed by a proposed stepwise hydrogen-atom abstraction and rapid radical recombination to furnish the resulting C-N bond. The proposed mechanism and experimental analysis are further corroborated by density functional theory calculations. Multiconfigurational calculations provide insight into the electronic structure of the catalytically relevant Cu nitrene intermediates. The findings presented herein will assist in the development of future methodology for Cu-mediated C-N bond forming catalysis.
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Affiliation(s)
- Kurtis M Carsch
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02138 USA
| | - Sasha C North
- Center for Advanced Scientific Computing and Modeling (CASCaM), Department of Chemistry, University of North Texas, Denton TX 76203 USA
| | - Ida M DiMucci
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University Ithaca New York 14853 USA
| | - Andrei Iliescu
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02138 USA
| | - Petra Vojáčková
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02138 USA
| | - Thomas Khazanov
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University Ithaca New York 14853 USA
| | - Shao-Liang Zheng
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02138 USA
| | - Thomas R Cundari
- Center for Advanced Scientific Computing and Modeling (CASCaM), Department of Chemistry, University of North Texas, Denton TX 76203 USA
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University Ithaca New York 14853 USA
| | - Theodore A Betley
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02138 USA
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7
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Gonzalez A, Demeshko S, Meyer F, Werncke CG. A low-coordinate iron organoazide complex. Chem Commun (Camb) 2023; 59:11532-11535. [PMID: 37672291 DOI: 10.1039/d3cc03765g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
A labile organoazide iron complex is reported. Under ambient conditions, the azide adduct is subject to a dissociation equilibrium in solution, yet also undergoes intramolecular C-H bond amination. Single-crystal irradiation of the azide at 80 K leads to partial N2-extrusion and formation of a putative imido iron intermediate, which was computationally identified as a highly covalent {FeNR}8 species.
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Affiliation(s)
- Andres Gonzalez
- Philipps-University Marburg, Hans-Meerwein-Straße 4, Marburg D-35032, Germany.
| | - Serhiy Demeshko
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstr. 4, Göttingen D-37077, Germany
| | - Franc Meyer
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstr. 4, Göttingen D-37077, Germany
| | - C Gunnar Werncke
- Philipps-University Marburg, Hans-Meerwein-Straße 4, Marburg D-35032, Germany.
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8
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Kim S, Song SL, Zhang J, Kim D, Hong S, Chang S. Regio- and Enantioselective Catalytic δ-C-H Amidation of Dioxazolones Enabled by Open-Shell Copper-Nitrenoid Transfer. J Am Chem Soc 2023; 145:16238-16248. [PMID: 37462685 DOI: 10.1021/jacs.3c05258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
Controlling regio- and enantioselectivity in C-H functionalization reactions is of paramount importance due to their versatile synthetic utilities. Herein, we describe a new approach for the asymmetric δ-C(sp3)-H amidation catalysis of dioxazolones using a Cu(I) precursor with a chiral bisoxazoline ligand to access six-membered lactams with high to excellent regio- and enantioselectivity (up to >19:1 rr and >99:1 er). Combined experimental and computational mechanistic studies unveiled that the open-shell character of the postulated Cu-nitrenoids enables the regioselective hydrogen atom abstraction and subsequent enantio-determining radical rebound of the resulting carbon radical intermediates. The synthetic utility of this asymmetric cyclization was demonstrated in the diastereoselective introduction of additional functional groups into the chiral δ-lactam skeleton as well as in the rapid access to biorelevant azacyclic compounds.
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Affiliation(s)
- Suhyeon Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea
| | - Se Lin Song
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea
| | - Jianbo Zhang
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea
| | - Dongwook Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea
| | - Sungwoo Hong
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea
| | - Sukbok Chang
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea
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9
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Chen X, Lian Z, Kramer S. Enantioselective Intermolecular Radical Amidation and Amination of Benzylic C-H Bonds via Dual Copper and Photocatalysis. Angew Chem Int Ed Engl 2023; 62:e202217638. [PMID: 36721305 DOI: 10.1002/anie.202217638] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/23/2023] [Accepted: 01/31/2023] [Indexed: 02/02/2023]
Abstract
A method for direct access to enantioenriched benzylic amides and carbamate-protected primary benzylamines by C-H functionalization is reported. The C-H substrate is used as limiting reagent with only a small excess of the unactivated amide or carbamate nucleophile. The enantioselective intermolecular dehydrogenative C-N bond formation is enabled by a combination of a chiral copper catalyst, a photocatalyst, and an oxidant, and it takes place under mild conditions, which allow for a broad substrate scope. The method is compatible with late-stage C-H functionalization, and it provides easy access to 15 N-labeled amides and amines starting from cheap 15 NH4 Cl.
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Affiliation(s)
- Xuemeng Chen
- Department of Chemistry, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
| | - Zhong Lian
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital and West China School of Pharmacy, Sichuan University, China
| | - Søren Kramer
- Department of Chemistry, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
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10
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Intranuovo F, Brunetti L, DelRe P, Mangiatordi GF, Stefanachi A, Laghezza A, Niso M, Leonetti F, Loiodice F, Ligresti A, Kostrzewa M, Brea J, Loza MI, Sotelo E, Saviano M, Colabufo NA, Riganti C, Abate C, Contino M. Development of N-(1-Adamantyl)benzamides as Novel Anti-Inflammatory Multitarget Agents Acting as Dual Modulators of the Cannabinoid CB2 Receptor and Fatty Acid Amide Hydrolase. J Med Chem 2023; 66:235-250. [PMID: 36542836 DOI: 10.1021/acs.jmedchem.2c01084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cannabinoid type 2 receptor (CB2R), belonging to the endocannabinoid system, is overexpressed in pathologies characterized by inflammation, and its activation counteracts inflammatory states. Fatty acid amide hydrolase (FAAH) is an enzyme responsible for the degradation of the main endocannabinoid anandamide; thus, the simultaneous CB2R activation and FAAH inhibition may be a synergistic anti-inflammatory strategy. Encouraged by principal component analysis (PCA) data identifying a wide chemical space shared by CB2R and FAAH ligands, we designed a small library of adamantyl-benzamides, as potential dual agents, CB2R agonists, and FAAH inhibitors. The new compounds were tested for their CB2R affinity/selectivity and CB2R and FAAH activity. Derivatives 13, 26, and 27, displaying the best pharmacodynamic profile as CB2R full agonists and FAAH inhibitors, decreased pro-inflammatory and increased anti-inflammatory cytokines production. Molecular docking simulations complemented the experimental findings by providing a molecular rationale behind the observed activities. These multitarget ligands constitute promising anti-inflammatory agents.
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Affiliation(s)
- Francesca Intranuovo
- Dipartimento di Farmacia-Scienze Del Farmaco, Università Degli Studi di Bari ALDO MORO, Via Orabona 4, Bari 70125, Italy
| | - Leonardo Brunetti
- Dipartimento di Farmacia-Scienze Del Farmaco, Università Degli Studi di Bari ALDO MORO, Via Orabona 4, Bari 70125, Italy
| | - Pietro DelRe
- Institute of Crystallography, National Research Council of Italy, Via Amendola, 122/o, Bari 70126, Italy
| | | | - Angela Stefanachi
- Dipartimento di Farmacia-Scienze Del Farmaco, Università Degli Studi di Bari ALDO MORO, Via Orabona 4, Bari 70125, Italy
| | - Antonio Laghezza
- Dipartimento di Farmacia-Scienze Del Farmaco, Università Degli Studi di Bari ALDO MORO, Via Orabona 4, Bari 70125, Italy
| | - Mauro Niso
- Dipartimento di Farmacia-Scienze Del Farmaco, Università Degli Studi di Bari ALDO MORO, Via Orabona 4, Bari 70125, Italy
| | - Francesco Leonetti
- Dipartimento di Farmacia-Scienze Del Farmaco, Università Degli Studi di Bari ALDO MORO, Via Orabona 4, Bari 70125, Italy
| | - Fulvio Loiodice
- Dipartimento di Farmacia-Scienze Del Farmaco, Università Degli Studi di Bari ALDO MORO, Via Orabona 4, Bari 70125, Italy
| | - Alessia Ligresti
- Institute of Biomolecular Chemistry, National Research Council of Italy, Via Campi Flegrei 34, Pozzuoli 80078, Italy
| | - Magdalena Kostrzewa
- Institute of Biomolecular Chemistry, National Research Council of Italy, Via Campi Flegrei 34, Pozzuoli 80078, Italy
| | - Jose Brea
- Innopharma Screening Platform, BioFarma Research Group, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela 15782, Spain.,Department of Pharmacology, Pharmacy and Pharmaceutical Technology. School of Pharmacy, University of Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Maria Isabel Loza
- Innopharma Screening Platform, BioFarma Research Group, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela 15782, Spain.,Department of Pharmacology, Pharmacy and Pharmaceutical Technology. School of Pharmacy, University of Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Eddy Sotelo
- ComBioMed Research Group, Centro de Química Biológica y Materiales Moleculares (CIQUS), University of Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Michele Saviano
- Institute of Crystallography, National Research Council of Italy, Via Vivaldi, 43, Caserta 81100, Italy
| | - Nicola Antonio Colabufo
- Dipartimento di Farmacia-Scienze Del Farmaco, Università Degli Studi di Bari ALDO MORO, Via Orabona 4, Bari 70125, Italy
| | - Chiara Riganti
- Dipartimento di Oncologia, Università Degli Studi di Torino, Torino 10126, Italy
| | - Carmen Abate
- Dipartimento di Farmacia-Scienze Del Farmaco, Università Degli Studi di Bari ALDO MORO, Via Orabona 4, Bari 70125, Italy.,Institute of Crystallography, National Research Council of Italy, Via Amendola, 122/o, Bari 70126, Italy
| | - Marialessandra Contino
- Dipartimento di Farmacia-Scienze Del Farmaco, Università Degli Studi di Bari ALDO MORO, Via Orabona 4, Bari 70125, Italy
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11
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Chen J, Wang H, Day CS, Martin R. Nickel-Catalyzed Site-Selective Intermolecular C(sp 3 )-H Amidation. Angew Chem Int Ed Engl 2022; 61:e202212983. [PMID: 36254803 DOI: 10.1002/anie.202212983] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Indexed: 11/06/2022]
Abstract
A nickel-catalyzed site-selective intermolecular amidation of saturated C(sp3 )-H bonds is reported. This mild protocol exhibits a predictable reactivity pattern to incorporate amide functions at C(sp3 )-H sites adjacent to nitrogen and oxygen atoms in either cyclic or acyclic frameworks, thus offering a complementary reactivity profile to existing oxidative-type processes or metal-catalyzed C(sp3 )-N bond-forming reactions operating via two-electron manifolds.
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Affiliation(s)
- Jinhong Chen
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, c/Marcel ⋅ lí Domingo, 1, 43007, Tarragona, Spain
| | - Hao Wang
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, c/Marcel ⋅ lí Domingo, 1, 43007, Tarragona, Spain
| | - Craig S Day
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, c/Marcel ⋅ lí Domingo, 1, 43007, Tarragona, Spain
| | - Ruben Martin
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain
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12
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Zhou S, Liu T, Bao X. Direct intermolecular C(sp)–H amidation with dioxazolones via synergistic decatungstate anion photocatalysis and nickel catalysis: A combined experimental and computational study. J Catal 2022. [DOI: 10.1016/j.jcat.2022.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Call A, Cianfanelli M, Besalú-Sala P, Olivo G, Palone A, Vicens L, Ribas X, Luis JM, Bietti M, Costas M. Carboxylic Acid Directed γ-Lactonization of Unactivated Primary C-H Bonds Catalyzed by Mn Complexes: Application to Stereoselective Natural Product Diversification. J Am Chem Soc 2022; 144:19542-19558. [PMID: 36228322 DOI: 10.1021/jacs.2c08620] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reactions that enable selective functionalization of strong aliphatic C-H bonds open new synthetic paths to rapidly increase molecular complexity and expand chemical space. Particularly valuable are reactions where site-selectivity can be directed toward a specific C-H bond by catalyst control. Herein we describe the catalytic site- and stereoselective γ-lactonization of unactivated primary C-H bonds in carboxylic acid substrates. The system relies on a chiral Mn catalyst that activates aqueous hydrogen peroxide to promote intramolecular lactonization under mild conditions, via carboxylate binding to the metal center. The system exhibits high site-selectivity and enables the oxidation of unactivated primary γ-C-H bonds even in the presence of intrinsically weaker and a priori more reactive secondary and tertiary ones at α- and β-carbons. With substrates bearing nonequivalent γ-C-H bonds, the factors governing site-selectivity have been uncovered. Most remarkably, by manipulating the absolute chirality of the catalyst, γ-lactonization at methyl groups in gem-dimethyl structural units of rigid cyclic and bicyclic carboxylic acids can be achieved with unprecedented levels of diastereoselectivity. Such control has been successfully exploited in the late-stage lactonization of natural products such as camphoric, camphanic, ketopinic, and isoketopinic acids. DFT analysis points toward a rebound type mechanism initiated by intramolecular 1,7-HAT from a primary γ-C-H bond of the bound substrate to a highly reactive MnIV-oxyl intermediate, to deliver a carbon radical that rapidly lactonizes through carboxylate transfer. Intramolecular kinetic deuterium isotope effect and 18O labeling experiments provide strong support to this mechanistic picture.
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Affiliation(s)
- Arnau Call
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Marco Cianfanelli
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Pau Besalú-Sala
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Giorgio Olivo
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Andrea Palone
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain.,Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata", Via della Ricerca Scientifica 1, I-00133 Rome, Italy
| | - Laia Vicens
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Xavi Ribas
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Josep M Luis
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
| | - Massimo Bietti
- Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata", Via della Ricerca Scientifica 1, I-00133 Rome, Italy
| | - Miquel Costas
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17003, Catalonia, Spain
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14
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Figula BC, Chen TA, Bertke JA, Warren TH. Copper-Catalyzed C(sp3)–H Methylation via Radical Relay. ACS Catal 2022. [DOI: 10.1021/acscatal.2c02474] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Bryan C. Figula
- Department of Chemistry, Georgetown University, Box 571227-1227, Washington, D.C. 20057, United States
| | - Ting-An Chen
- Department of Chemistry, Georgetown University, Box 571227-1227, Washington, D.C. 20057, United States
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Jeffery A. Bertke
- Department of Chemistry, Georgetown University, Box 571227-1227, Washington, D.C. 20057, United States
| | - Timothy H. Warren
- Department of Chemistry, Georgetown University, Box 571227-1227, Washington, D.C. 20057, United States
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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15
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Du B, Chan CM, Au CM, Yu WY. Transition Metal-Catalyzed Regioselective Direct C–H Amidation: Interplay between Inner- and Outer-Sphere Pathways for Nitrene Cross-Coupling Reactions. Acc Chem Res 2022; 55:2123-2137. [DOI: 10.1021/acs.accounts.2c00283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Bingnan Du
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Chun-Ming Chan
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Chi-Ming Au
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Wing-Yiu Yu
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
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16
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Xing Q, Jiang D, Zhang J, Guan L, Li T, Zhao Y, Di M, Chen H, Che C, Zhu Z. Combining visible-light induction and copper catalysis for chemo-selective nitrene transfer for late-stage amination of natural products. Commun Chem 2022; 5:79. [PMID: 36697627 PMCID: PMC9814389 DOI: 10.1038/s42004-022-00692-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 06/22/2022] [Indexed: 01/28/2023] Open
Abstract
Nitrene transfer chemistry is an effective strategy for introducing C-N bonds, which are ubiquitous in pharmaceuticals, agrochemicals and diverse bioactive natural products. The development of chemical methodology that can functionalize unique sites within natural products through nitrene transfer remains a challenge in the field. Herein, we developed copper catalyzed chemoselective allylic C-H amination and catalyst-free visible-light induced aziridination of alkenes through nitrene transfer. In general, both reactions tolerate a wide range of functional groups and occur with predictable regioselectivity. Furthermore, combination of these two methods enable the intermolecular chemo-selective late-stage amination of biologically active natural products, leading to C-H amination or C=C aziridination products in a tunable way. A series of control experiments indicate two-step radical processes were involved in both reaction systems.
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Affiliation(s)
- Qi Xing
- BayRay Innovation Center, Shenzhen Bay Laboratory, Shenzhen, 518132, China.
| | - Ding Jiang
- BayRay Innovation Center, Shenzhen Bay Laboratory, Shenzhen, 518132, China
| | - Jiayin Zhang
- BayRay Innovation Center, Shenzhen Bay Laboratory, Shenzhen, 518132, China
| | - Liangyu Guan
- BayRay Innovation Center, Shenzhen Bay Laboratory, Shenzhen, 518132, China
| | - Ting Li
- BayRay Innovation Center, Shenzhen Bay Laboratory, Shenzhen, 518132, China
| | - Yi Zhao
- BayRay Innovation Center, Shenzhen Bay Laboratory, Shenzhen, 518132, China
| | - Man Di
- BayRay Innovation Center, Shenzhen Bay Laboratory, Shenzhen, 518132, China
| | - Huangcan Chen
- BayRay Innovation Center, Shenzhen Bay Laboratory, Shenzhen, 518132, China
| | - Chao Che
- BayRay Innovation Center, Shenzhen Bay Laboratory, Shenzhen, 518132, China.
- State Key Laboratory of Chemical Oncogenomics and Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
| | - Zhendong Zhu
- BayRay Innovation Center, Shenzhen Bay Laboratory, Shenzhen, 518132, China.
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17
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Wang Z, Wang F. Radical‐Mediated
Selective Functionalization of Unactivated Primary C–H Bonds. CHINESE J CHEM 2022. [DOI: 10.1002/cjoc.202200210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Zhan‐Lin Wang
- State Key Laboratory of Elemento‐Organic Chemistry, College of Chemistry, Nankai University Tianjin 300071 China
| | - Fei Wang
- State Key Laboratory of Elemento‐Organic Chemistry, College of Chemistry, Nankai University Tianjin 300071 China
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18
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Chellali JE, Alverson AK, Robinson JR. Zinc Aryl/Alkyl β-diketiminates: Balancing Accessibility and Stability for High-Activity Ring-Opening Polymerization of rac-Lactide. ACS Catal 2022. [DOI: 10.1021/acscatal.2c00858] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jonathan E. Chellali
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Alexander K. Alverson
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Jerome R. Robinson
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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19
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Gonzalez MI, Gygi D, Qin Y, Zhu Q, Johnson EJ, Chen YS, Nocera DG. Taming the Chlorine Radical: Enforcing Steric Control over Chlorine-Radical-Mediated C-H Activation. J Am Chem Soc 2022; 144:1464-1472. [PMID: 35020391 DOI: 10.1021/jacs.1c13333] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chlorine radicals readily activate C-H bonds, but the high reactivity of these intermediates precludes their use in regioselective C-H functionalization reactions. We demonstrate that the secondary coordination sphere of a metal complex can confine photoeliminated chlorine radicals and afford steric control over their reactivity. Specifically, a series of iron(III) chloride pyridinediimine complexes exhibit activity for photochemical C(sp3)-H chlorination and bromination with selectivity for primary and secondary C-H bonds, overriding thermodynamic preference for weaker tertiary C-H bonds. Transient absorption spectroscopy reveals that Cl· remains confined through formation of a Cl·|arene complex with aromatic groups on the pyridinediimine ligand. Furthermore, photocrystallography confirms that this selectivity arises from the generation of Cl· within the steric environment defined by the iron secondary coordination sphere.
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Affiliation(s)
- Miguel I Gonzalez
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - David Gygi
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Yangzhong Qin
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Qilei Zhu
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Elizabeth J Johnson
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Yu-Sheng Chen
- ChemMatCARS, The University of Chicago, Argonne, Illinois 60439, United States
| | - Daniel G Nocera
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
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20
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Cammarota RC, Liu W, Bacsa J, Davies HML, Sigman MS. Mechanistically Guided Workflow for Relating Complex Reactive Site Topologies to Catalyst Performance in C–H Functionalization Reactions. J Am Chem Soc 2022; 144:1881-1898. [DOI: 10.1021/jacs.1c12198] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Ryan C. Cammarota
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Wenbin Liu
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - John Bacsa
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Huw M. L. Davies
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Matthew S. Sigman
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
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21
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Li F, Liang Y, Zhan X, Zhang S, Li MB. Electricity-driven redox-neutral C(sp 3)–H amidation with N-alkoxyamide as an amidating reagent. Org Chem Front 2022. [DOI: 10.1039/d2qo01108e] [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
An electrochemical redox-neutral C(sp3)–H amidation was developed with N-alkoxyamide as an amidating reagent. Under sequential paired electrolysis, N-alkoxyamides showed higher reactivity compared to the direct reaction of primary amides.
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Affiliation(s)
- Fengyi Li
- Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, China
| | - Yating Liang
- Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, China
| | - Xuan Zhan
- Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, China
| | - Sheng Zhang
- Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, China
| | - Man-Bo Li
- Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, China
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22
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Reith S, Demeshko S, Battistella B, Reckziegel A, Schneider C, Stoy A, Lichtenberg C, Meyer F, Munz D, Werncke CG. Between imide, imidyl and nitrene – an imido iron complex in two oxidation states. Chem Sci 2022; 13:7907-7913. [PMID: 35865905 PMCID: PMC9258327 DOI: 10.1039/d2sc01088g] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 05/28/2022] [Indexed: 01/11/2023] Open
Abstract
Imidyl and nitrene metal species play an important role in the N-functionalisation of unreactive C–H bonds as well as the aziridination of olefines. We report on the synthesis of the trigonal imido iron complexes [Fe(NMes)L2]0,− (L = –N{Dipp}SiMe3); Dipp = 2,6-diisopropyl-phenyl; Mes = (2,4,6-trimethylphenyl) via reaction of mesityl azide (MesN3) with the linear iron precursors [FeL2]0,−. UV-vis-, EPR-, 57Fe Mössbauer spectroscopy, magnetometry, and computational methods suggest for the reduced form an electronic structure as a ferromagnetically coupled iron(ii) imidyl radical, whereas oxidation leads to mixed iron(iii) imidyl and electrophilic iron(ii) nitrene character. Reactivity studies show that both complexes are capable of H atom abstraction from C–H bonds. Further, the reduced form [Fe(NMes)L2]− reacts nucleophilically with CS2 by inserting into the imido iron bond, as well as electrophilically with CO under nitrene transfer. The neutral [Fe(NMes)L2] complex shows enhanced electrophilic behavior as evidenced by nitrene transfer to a phosphine, yet in combination with an overall reduced reactivity. A pair of trigonal imido iron complexes ([Fe(NMes)L2]0,−) in two oxidation states is reported. The anionic complex K{crypt.222}[Fe(NMes)L2] is best described as an iron(ii) imide.![]()
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Affiliation(s)
- Sascha Reith
- Philipps-University Marburg, Department of Chemistry, Hans-Meerwein-Str. 4, D-35037 Marburg, Germany
| | - Serhiy Demeshko
- University of Göttingen, Institute of Inorganic Chemistry, Tammannstr. 4, D-37077 Göttingen, Germany
| | - Beatrice Battistella
- Humboldt-University, Berlin Institute for Chemistry, Brook-Taylor-Str. 2, D-12489 Berlin, Germany
| | - Alexander Reckziegel
- Philipps-University Marburg, Department of Chemistry, Hans-Meerwein-Str. 4, D-35037 Marburg, Germany
| | - Christian Schneider
- Philipps-University Marburg, Department of Chemistry, Hans-Meerwein-Str. 4, D-35037 Marburg, Germany
| | - Andreas Stoy
- Philipps-University Marburg, Department of Chemistry, Hans-Meerwein-Str. 4, D-35037 Marburg, Germany
| | - Crispin Lichtenberg
- Philipps-University Marburg, Department of Chemistry, Hans-Meerwein-Str. 4, D-35037 Marburg, Germany
| | - Franc Meyer
- University of Göttingen, Institute of Inorganic Chemistry, Tammannstr. 4, D-37077 Göttingen, Germany
| | - Dominik Munz
- Saarland University, Inorganic Chemistry: Coordination Chemistry, Campus C4.1, D-66123 Saarbrücken, Germany
- Friedrich-Alexander University Erlangen-Nürnberg, Inorganic Chemistry, Egerlandstr. 1, D-91058 Erlangen, Germany
| | - C. Gunnar Werncke
- Philipps-University Marburg, Department of Chemistry, Hans-Meerwein-Str. 4, D-35037 Marburg, Germany
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23
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Kato T, Maruoka K. Selective functionalization of benzylic C-H bonds of two different benzylic ethers by bowl-shaped N-hydroxyimide derivatives as efficient organoradical catalysts. Chem Commun (Camb) 2021; 58:1021-1024. [PMID: 34951412 DOI: 10.1039/d1cc06425h] [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
A highly efficient, site-selective benzylic C-H bond amination of two different benzylic ether substrates was described by using bowl-shaped N-hydroxyimide organoradical catalysts with diethyl azodicarboxylate. The synthetic utility of this approach is demonstrated by the subsequent transformation of the amination products into the corresponding aldehydes and alkylhydrazines.
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Affiliation(s)
- Terumasa Kato
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China.,Guangdong Provincial Key Laboratory of Plant Resources Biorefinery, Guangdong University of Technology, Guangzhou 510006, China.,Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan.
| | - Keiji Maruoka
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China.,Guangdong Provincial Key Laboratory of Plant Resources Biorefinery, Guangdong University of Technology, Guangzhou 510006, China.,Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan.
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24
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Chiral bis(pyrazolyl)methane copper(I) complexes and their application in nitrene transfer reactions. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2021. [DOI: 10.1515/znb-2021-0140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
In this study, chiral bis(pyrazolyl)methane copper(I) acetonitrile complexes were applied to generate two novel terminal copper tosyl nitrene complexes with the nitrene generating agent SPhINTs in dichloromethane at low temperatures. The syntheses of the chiral bis(pyrazolyl)methane ligands are based on pulegone and camphor, members of the natural chiral pool. The chiral copper(I) acetonitrile complexes were applied as catalysts in the copper nitrene mediated aziridination reaction of different styrene derivatives and the C–H amination of various substrates. The reactions afforded good yields, but low enantiomeric excess under mild conditions. The nitrene species have been characterized with UV/Vis and EPR spectroscopy and the products of the decay by ESI mass spectrometry.
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25
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Affiliation(s)
- Hidetoshi Noda
- Institute of Microbial Chemistry 3-14-23 Kamiosaki, Shinagaku-ku Tokyo 141-0021 Japan
| | - Xinxin Tang
- Institute of Microbial Chemistry 3-14-23 Kamiosaki, Shinagaku-ku Tokyo 141-0021 Japan
| | - Masakatsu Shibasaki
- Institute of Microbial Chemistry 3-14-23 Kamiosaki, Shinagaku-ku Tokyo 141-0021 Japan
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26
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Du B, Ouyang Y, Chen Q, Yu WY. Thioether-Directed NiH-Catalyzed Remote γ-C(sp 3)-H Hydroamidation of Alkenes by 1,4,2-Dioxazol-5-ones. J Am Chem Soc 2021; 143:14962-14968. [PMID: 34496211 DOI: 10.1021/jacs.1c05834] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A NiH-catalyzed thioether-directed cyclometalation strategy is developed to enable remote methylene C-H bond amidation of unactivated alkenes. Due to the preference for five-membered nickelacycle formation, the chain-walking isomerization initiated by the NiH insertion to an alkene can be terminated at the γ-methylene site remote from the alkene moiety. By employing 2,9-dibutyl-1,10-phenanthroline (L4) as the ligand and dioxazolones as the reagent, the amidation occurs at the γ-C(sp3)-H bonds to afford the amide products in up to 90% yield (>40 examples) with remarkable regioselectivity (up to 24:1 rr).
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Affiliation(s)
- Bingnan Du
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Yuxin Ouyang
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Qishu Chen
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Wing-Yiu Yu
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
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27
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Grünwald A, Anjana SS, Munz D. Terminal Imido Complexes of the Groups 9–11: Electronic Structure and Developments in the Last Decade. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100410] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Annette Grünwald
- Inorganic Chemistry: Coordination Chemistry Saarland University Campus Geb. C4.1 66123 Saarbücken Germany
- Inorganic and General Chemistry Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg Egerlandstr. 1 91058 Erlangen Germany
| | - S. S. Anjana
- Inorganic Chemistry: Coordination Chemistry Saarland University Campus Geb. C4.1 66123 Saarbücken Germany
| | - Dominik Munz
- Inorganic Chemistry: Coordination Chemistry Saarland University Campus Geb. C4.1 66123 Saarbücken Germany
- Inorganic and General Chemistry Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg Egerlandstr. 1 91058 Erlangen Germany
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28
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Fuentes MÁ, Gava R, Saper NI, Romero EA, Caballero A, Hartwig JF, Pérez PJ. Copper‐Catalyzed Dehydrogenative Amidation of Light Alkanes. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202104737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- M. Ángeles Fuentes
- Laboratorio de Catálisis Homogénea Unidad Asociada al CSIC CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química Universidad de Huelva 21007 Huelva Spain
| | - Riccardo Gava
- Laboratorio de Catálisis Homogénea Unidad Asociada al CSIC CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química Universidad de Huelva 21007 Huelva Spain
| | - Noam I. Saper
- Department of Chemistry University of California Berkeley CA 94720 USA
| | - Erik A. Romero
- Department of Chemistry University of California Berkeley CA 94720 USA
| | - Ana Caballero
- Laboratorio de Catálisis Homogénea Unidad Asociada al CSIC CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química Universidad de Huelva 21007 Huelva Spain
| | - John F. Hartwig
- Department of Chemistry University of California Berkeley CA 94720 USA
| | - Pedro J. Pérez
- Laboratorio de Catálisis Homogénea Unidad Asociada al CSIC CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química Universidad de Huelva 21007 Huelva Spain
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29
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Hong D, Liu Y, Wu L, Lo VK, Toy PH, Law S, Huang J, Che C. Ru
V
‐Acylimido Intermediate in [Ru
IV
(Por)Cl
2
]‐Catalyzed C–N Bond Formation: Spectroscopic Characterization, Reactivity, and Catalytic Reactions. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202100668] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Dan‐Yan Hong
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong SAR China
| | - Yungen Liu
- Department of Chemistry Southern University of Science and Technology Shenzhen Guangdong 518055 China
| | - Liangliang Wu
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong SAR China
| | - Vanessa Kar‐Yan Lo
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong SAR China
| | - Patrick H. Toy
- Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong SAR China
| | - Siu‐Man Law
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong SAR China
| | - Jie‐Sheng Huang
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong SAR China
| | - Chi‐Ming Che
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong SAR China
- Department of Chemistry Southern University of Science and Technology Shenzhen Guangdong 518055 China
- HKU Shenzhen Institute of Research and Innovation Shenzhen 518053 China
- Laboratory for Synthetic Chemistry and Chemical Biology Limited Units 1503–1511, 15/F., Building 17W, Hong Kong Science and Technology Parks, New Territories Hong Kong SAR China
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30
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Fuentes MÁ, Gava R, Saper NI, Romero EA, Caballero A, Hartwig JF, Pérez PJ. Copper-Catalyzed Dehydrogenative Amidation of Light Alkanes. Angew Chem Int Ed Engl 2021; 60:18467-18471. [PMID: 33979475 PMCID: PMC8457245 DOI: 10.1002/anie.202104737] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Indexed: 01/18/2023]
Abstract
The functionalization of C-H bonds in light alkanes, particularly to form C-N bonds, remains a challenge. We report the dehydrogenative coupling of amides with C1-C4 hydrocarbons to form N-alkyl amide products with tBuOOtBu as oxidant, and a copper complex of a phenanthroline-type ligand as catalyst. The reactions occurred in good yields in benzene or supercritical carbon dioxide as solvents. This strategy allowed for the determination of the relative reactivity of these alkane C-H bonds toward this amination process and showed, in contrast to prior work with larger alkanes, that the reactivity correlated with bond dissociation energies.
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Affiliation(s)
- M Ángeles Fuentes
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, 21007, Huelva, Spain
| | - Riccardo Gava
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, 21007, Huelva, Spain
| | - Noam I Saper
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Erik A Romero
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Ana Caballero
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, 21007, Huelva, Spain
| | - John F Hartwig
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Pedro J Pérez
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, 21007, Huelva, Spain
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31
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Hong DY, Liu Y, Wu L, Lo VKY, Toy PH, Law SM, Huang JS, Che CM. Ru V -Acylimido Intermediate in [Ru IV (Por)Cl 2 ]-Catalyzed C-N Bond Formation: Spectroscopic Characterization, Reactivity, and Catalytic Reactions. Angew Chem Int Ed Engl 2021; 60:18619-18629. [PMID: 33847064 DOI: 10.1002/anie.202100668] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/16/2021] [Indexed: 01/12/2023]
Abstract
Metal-catalyzed C-N bond formation reactions via acylnitrene transfer have recently attracted much attention, but direct detection of the proposed acylnitrenoid/acylimido M(NCOR) (R=aryl or alkyl) species in these reactions poses a formidable challenge. Herein, we report on Ru(NCOR) intermediates in C-N bond formation catalyzed by [RuIV (Por)Cl2 ]/N3 COR, a catalytic method applicable to aziridine/oxazoline formation from alkenes, amination of substituted indoles, α-amino ketone formation from silyl enol ethers, amination of C(sp3 )-H bonds, and functionalization of natural products and carbohydrate derivatives (up to 99 % yield). Experimental studies, including HR-ESI-MS and EPR measurements, coupled with DFT calculations, lend evidence for the formulation of the Ru(NCOR) acylnitrenoids as a RuV -imido species.
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Affiliation(s)
- Dan-Yan Hong
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Yungen Liu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Liangliang Wu
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Vanessa Kar-Yan Lo
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Patrick H Toy
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Siu-Man Law
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Jie-Sheng Huang
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.,Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.,HKU Shenzhen Institute of Research and Innovation, Shenzhen, 518053, China.,Laboratory for Synthetic Chemistry and Chemical Biology Limited, Units 1503-1511, 15/F., Building 17W, Hong Kong Science and Technology Parks, New Territories, Hong Kong SAR, China
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32
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Thomas F, Oster M, Schön F, Göbgen KC, Amarouch B, Steden D, Hoffmann A, Herres-Pawlis S. A new generation of terminal copper nitrenes and their application in aromatic C-H amination reactions. Dalton Trans 2021; 50:6444-6462. [PMID: 33908532 DOI: 10.1039/d1dt00832c] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Copper nitrene complexes are highly reactive species and are known as intermediates in the copper catalyzed C-H amination. In this study, three novel copper tosyl nitrene complexes were synthesized at low temperatures, stabilized with heteroscorpionate ligands of the bis(pyrazolyl)methane family. The copper nitrenes were obtained by the reaction of a copper(i) acetonitrile complex with SPhINTs in dichloromethane. We show that the ligand design has a major influence on the catalytic activity and the thermal stability of the copper nitrene complex. Not only the choice of the third N donor, but also the substituent in the 5-position of the pyrazolyl moiety, have an impact on the stability. Furthermore, the novel copper nitrene complexes were used for catalytic aziridination of styrenes and C-H amination reactions of aromatic and aliphatic substrates under mild reaction conditions. Even challenging substrates like benzene and cyclohexane were aminated with good yields. The copper nitrene complexes were characterized using UV/Vis spectroscopy, low temperature Evans NMR spectroscopy, density functional theory, domain-based local pair natural orbital coupled cluster calculations (DLPNO-CCSD(T)) and cryo-UHR mass spectrometry.
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Affiliation(s)
- Fabian Thomas
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074 Aachen, Germany.
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33
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Brunard E, Boquet V, Van Elslande E, Saget T, Dauban P. Catalytic Intermolecular C(sp 3)-H Amination: Selective Functionalization of Tertiary C-H Bonds vs Activated Benzylic C-H Bonds. J Am Chem Soc 2021; 143:6407-6412. [PMID: 33900759 DOI: 10.1021/jacs.1c03872] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A catalytic intermolecular amination of nonactivated tertiary C(sp3)-H bonds (BDE of 96 kcal·mol-1) is reported for substrates displaying an activated benzylic site (BDE of 85 kcal·mol-1). The tertiary C(sp3)-H bond is selectively functionalized to afford α,α,α-trisubstituted amides in high yields. This unusual site-selectivity results from the synergistic combination of Rh2(S-tfpttl)4, a rhodium(II) complex with a well-defined catalytic pocket, with tert-butylphenol sulfamate (TBPhsNH2), which leads to a discriminating rhodium-bound nitrene species under mild oxidative conditions. This catalytic system is very robust, and the reaction was performed on a 50 mmol scale with only 0.01 mol % of catalyst. The TBPhs group can be removed under mild conditions to afford the corresponding NH-free amines.
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Affiliation(s)
- Erwan Brunard
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France
| | - Vincent Boquet
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France
| | - Elsa Van Elslande
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France
| | - Tanguy Saget
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France
| | - Philippe Dauban
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France
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34
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Lee J, Jin S, Kim D, Hong SH, Chang S. Cobalt-Catalyzed Intermolecular C-H Amidation of Unactivated Alkanes. J Am Chem Soc 2021; 143:5191-5200. [PMID: 33780628 DOI: 10.1021/jacs.1c01524] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Alkanes are an abundant and inexpensive source of hydrocarbons; thus, development of new methods to convert the hydrocarbon feedstocks to value-added chemicals is of high interest. However, it is challenging to achieve such transformation in a direct and selective manner mainly due to the intrinsic inertness of their C-H bonds. We herein report a tailored Cp*Co(III)(LX)-catalyzed efficient and site-selective intermolecular amidation of unactivated hydrocarbons including light alkanes. Electronic modulation of the cobalt complexes led to the enhanced amidation efficiency, and these effects were theoretically rationalized by the FMO analysis of presupposed cobalt nitrenoid species. Under the current cobalt protocol, a secondary C-H bond selectivity was observed in various nonactivated alkanes to reverse the intrinsic tertiary preference, which is attributed to the steric demands of the cobalt system that imposes difficulties in accessing tertiary C-H bonds. Experimental and computational studies suggested that the putative triplet Co nitrenoids are transferred to the C-H bonds of alkanes via a radical-like hydrogen abstraction pathway.
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Affiliation(s)
- Jeonghyo Lee
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Seongho Jin
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Dongwook Kim
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Soon Hyeok Hong
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Sukbok Chang
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
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35
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Yang Y, Gao W, Wang Y, Wang X, Cao F, Shi T, Wang Z. Recent Advances in Copper Promoted Inert C(sp3)–H Functionalization. ACS Catal 2021. [DOI: 10.1021/acscatal.0c04618] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Yuhang Yang
- School of Pharmacy, Lanzhou University, West Donggang Road No. 199, Lanzhou 730000, Gansu, People’s Republic of China
| | - Weiwei Gao
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, Gansu, People’s Republic of China
| | - Yongqiang Wang
- School of Pharmacy, Lanzhou University, West Donggang Road No. 199, Lanzhou 730000, Gansu, People’s Republic of China
| | - Xiaodong Wang
- School of Pharmacy, Lanzhou University, West Donggang Road No. 199, Lanzhou 730000, Gansu, People’s Republic of China
| | - Fei Cao
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, Gansu, People’s Republic of China
| | - Tao Shi
- School of Pharmacy, Lanzhou University, West Donggang Road No. 199, Lanzhou 730000, Gansu, People’s Republic of China
| | - Zhen Wang
- School of Pharmacy, Lanzhou University, West Donggang Road No. 199, Lanzhou 730000, Gansu, People’s Republic of China
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, Gansu, People’s Republic of China
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36
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Song F, Zhu S, Wang H, Chen G. Iridium-Catalyzed Intermolecular N—N Coupling for Hydrazide Synthesis Using N-Benzoyloxycarbamates as Acyl Nitrene Precursor. CHINESE J ORG CHEM 2021. [DOI: 10.6023/cjoc202105044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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37
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Vasilopoulos A, Golden DL, Buss JA, Stahl SS. Copper-Catalyzed C-H Fluorination/Functionalization Sequence Enabling Benzylic C-H Cross Coupling with Diverse Nucleophiles. Org Lett 2020; 22:5753-5757. [PMID: 32790420 PMCID: PMC7446105 DOI: 10.1021/acs.orglett.0c02238] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Site-selective transformation of benzylic C-H bonds into diverse functional groups is achieved via Cu-catalyzed C-H fluorination with N-fluorobenzenesulfonimide (NFSI), followed by substitution of the resulting fluoride with various nucleophiles. The benzyl fluorides generated in these reactions are reactive electrophiles in the presence of hydrogen-bond donors or Lewis acids, allowing them to be used without isolation in C-O, C-N, and C-C coupling reactions.
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Affiliation(s)
- Aristidis Vasilopoulos
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, United States
| | - Dung L. Golden
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, United States
| | - Joshua A. Buss
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, United States
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, United States
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38
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Tian X, Song L, Hashmi ASK. Synthesis of Carbazoles and Related Heterocycles from Sulfilimines by Intramolecular C-H Aminations. Angew Chem Int Ed Engl 2020; 59:12342-12346. [PMID: 32045085 PMCID: PMC7384176 DOI: 10.1002/anie.202000146] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Indexed: 01/28/2023]
Abstract
While direct nitrene insertions into C-H bonds have become an important tool for building C-N bonds in modern organic chemistry, the generation of nitrene intermediates always requires transition metals, high temperatures, ultraviolet or laser light. We report a mild synthesis of carbazoles and related building blocks through a visible light-induced intramolecular C-H amination reaction. A striking advantage of this new method is the use of more reactive aryl sulfilimines instead of the corresponding hazardous azides. Different catalysts and divergent light sources were tested. The reaction scope is broad and the product yield is generally high. An efficient gram-scale synthesis of Clausine C demonstrates the applicability and scalability of this new method.
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Affiliation(s)
- Xianhai Tian
- Institut für Organische ChemieHeidelberg UniversityIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Lina Song
- Institut für Organische ChemieHeidelberg UniversityIm Neuenheimer Feld 27069120HeidelbergGermany
| | - A. Stephen K. Hashmi
- Institut für Organische ChemieHeidelberg UniversityIm Neuenheimer Feld 27069120HeidelbergGermany
- Chemistry DepartmentFaculty of ScienceKing Abdulaziz UniversityJeddah21589Saudi Arabia
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39
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Tian X, Song L, Hashmi ASK. Synthese von Carbazolen und Verwandten Heterocyclen aus Sulfiliminen durch Intramolekulare C‐H‐Aminierungen. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Xianhai Tian
- Institut für Organische Chemie Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - Lina Song
- Institut für Organische Chemie Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - A. Stephen K. Hashmi
- Institut für Organische Chemie Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
- Chemistry Department Faculty of Science King Abdulaziz University Jeddah 21589 Saudi Arabia
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40
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Zheng YW, Narobe R, Donabauer K, Yakubov S, König B. Copper(II)-Photocatalyzed N–H Alkylation with Alkanes. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01924] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yi-Wen Zheng
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Regensburg 93040, Germany
| | - Rok Narobe
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Regensburg 93040, Germany
| | - Karsten Donabauer
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Regensburg 93040, Germany
| | - Shahboz Yakubov
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Regensburg 93040, Germany
| | - Burkhard König
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Regensburg 93040, Germany
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41
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Song L, Claessen S, Van der Eycken EV. Pyridine-Enabled C-N Bond Activation for the Rapid Construction of Amides and 4-Pyridylglyoxamides by Cooperative Palladium/Copper Catalysis. J Org Chem 2020; 85:8045-8054. [PMID: 32441517 DOI: 10.1021/acs.joc.0c00845] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A pyridine-enabled C-N bond activation of peptidomimetics employing cooperative palladium/copper catalysis in water is developed. Diverse amides and 4-pyridylglyoxamides are simultaneously synthesized through two steps from commercially available materials in a rapid, environmentally friendly, and high atom-economical manner.
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Affiliation(s)
- Liangliang Song
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Sander Claessen
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Erik V Van der Eycken
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium.,Peoples' Friendship University of Russia (RUDN University), Miklukho-Maklaya street 6, Moscow 117198, Russia
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42
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Yoshitake M, Hayashi H, Uchida T. Ruthenium-Catalyzed Asymmetric N-Acyl Nitrene Transfer Reaction: Imidation of Sulfide. Org Lett 2020; 22:4021-4025. [DOI: 10.1021/acs.orglett.0c01373] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Masaki Yoshitake
- Department of Chemistry, Graduate School of Science, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Hiroki Hayashi
- Faculty of Arts and Science, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Tatsuya Uchida
- Faculty of Arts and Science, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
- International Institute of Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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43
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Yu Y, Luo G, Yang J, Luo Y. Theoretical studies on the N–X (X = Cl, O) bond activation mechanism in catalytic C–H amination. Catal Sci Technol 2020. [DOI: 10.1039/c9cy02555c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A favorable SN2-type N–Cl bond cleavage mechanism are proposed for Rh-catalysed C–H amination, which also works for N–O bond cleavage in Rh, Ru, and Pd analogous systems. These results could provide new understanding of C–H amination.
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Affiliation(s)
- Yang Yu
- State Key Laboratory of Fine Chemicals
- School of Chemical Engineering
- Dalian University of Technology
- Dalian 116024
- China
| | - Gen Luo
- Institutes of Physical Science and Information Technology
- Anhui University
- Hefei 230601
- China
| | - Jimin Yang
- State Key Laboratory of Fine Chemicals
- School of Chemical Engineering
- Dalian University of Technology
- Dalian 116024
- China
| | - Yi Luo
- State Key Laboratory of Fine Chemicals
- School of Chemical Engineering
- Dalian University of Technology
- Dalian 116024
- China
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44
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Betz KN, Chiappini ND, Du Bois J. Intermolecular sp3-C–H Amination for the Synthesis of Saturated Azacycles. Org Lett 2019; 22:1687-1691. [DOI: 10.1021/acs.orglett.9b04096] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Kerry N. Betz
- Department of Chemistry, Stanford University, 337 Campus Drive, Stanford, California 94305, United States
| | - Nicholas D. Chiappini
- Department of Chemistry, Stanford University, 337 Campus Drive, Stanford, California 94305, United States
| | - J. Du Bois
- Department of Chemistry, Stanford University, 337 Campus Drive, Stanford, California 94305, United States
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45
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King CR, Holdaway A, Durrant G, Wheeler J, Suaava L, Konnick MM, Periana RA, Ess DH. Supermetal: SbF 5-mediated methane oxidation occurs by C-H activation and isobutane oxidation occurs by hydride transfer. Dalton Trans 2019; 48:17029-17036. [PMID: 31693026 DOI: 10.1039/c9dt03564h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
SbVF5 is generally assumed to oxidize methane through a methanium-to-methyl cation mechanism. However, experimentally no H2 is observed, and the mechanism of methane oxidation has remained unsolved for several decades. To solve this problem, density functional theory calculations with multiple chemical models (mononuclear and dinuclear) were used to examine methane oxidation by SbVF5 in the presence of CO leading to the methyl acylium cation ([CH3CO]+). While there is a low barrier for methane protonation by [SbVF6]-[H]+ (the combination of SbVF5 and HF) to give the [SbVF5]-[CH5]+ ion pair, H2 dissociation is a relatively high energy process, even with CO assistance, and so this protonation pathway is reversible. While Sb-mediated hydride transfer has a reasonable barrier, the C-H activation/σ-bond metathesis mechanism with the formation of an SbV-Me intermediate is lower in energy. This pathway leads to the acylium cation by functionalization of the SbV-Me intermediate with CO and is consistent with no observation of H2. Because this C-H activation/metal-alkyl functionalization pathway is higher in energy than methane protonation, it is also consistent with the experimentally observed methane hydrogen-to-deuterium exchange. This is the first time that evidence is presented demonstrating that SbVF5 acts beyond a Bronsted superacid and involves C-H activation with an organometallic intermediate. In contrast to methane, due to the much lower carbocation hydride affinity, isobutane significantly favors hydride transfer to give the tert-butyl carbocation with concomitant SbV to SbIII reduction. In this mechanism, the resulting highly acidic SbV-H intermediate provides a route to H2 through protonation of isobutane, which is consistent with experiments and resolves the longstanding enigma of different experimental results for methane versus isobutane.
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Affiliation(s)
- Clinton R King
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
| | - Ashley Holdaway
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
| | - George Durrant
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
| | - Josh Wheeler
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
| | - Lorna Suaava
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
| | | | - Roy A Periana
- Department of Chemistry, The Scripps Research Institute, Jupiter, Florida 33458, USA.
| | - Daniel H Ess
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
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Tsygankov AA, Makarova M, Afanasyev OI, Kashin AS, Naumkin AV, Loginov DA, Chusov D. Reductive Amidation without an External Hydrogen Source Using Rhodium on Carbon Matrix as a Catalyst. ChemCatChem 2019. [DOI: 10.1002/cctc.201901465] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Alexey A. Tsygankov
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences 28 Vavilova str. Moscow 119991 Russia
| | - Maria Makarova
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences 28 Vavilova str. Moscow 119991 Russia
- Higher Chemical CollegeDmitry Mendeleev University of Chemical Technology of Russia Miusskaya sq. 9 Moscow 125047 Russia
| | - Oleg I. Afanasyev
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences 28 Vavilova str. Moscow 119991 Russia
| | - Alexey S. Kashin
- Zelinsky Institute of Organic ChemistryRussian Academy of Sciences Leninsky Prospekt 47 Moscow 119991 Russia
| | - Alexander V. Naumkin
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences 28 Vavilova str. Moscow 119991 Russia
- Moscow Institute of Physics and TechnologyState University Institutskiy Pereulok 9 Dolgoprudny 141701 Russia
| | - Dmitry A. Loginov
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences 28 Vavilova str. Moscow 119991 Russia
| | - Denis Chusov
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences 28 Vavilova str. Moscow 119991 Russia
- G.V. Plekhanov Russian University of Economics 36 Stremyanny Per. Moscow 117997 Russia
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DiMucci IM, Lukens JT, Chatterjee S, Carsch KM, Titus CJ, Lee SJ, Nordlund D, Betley TA, MacMillan SN, Lancaster KM. The Myth of d 8 Copper(III). J Am Chem Soc 2019; 141:18508-18520. [PMID: 31710466 PMCID: PMC7256958 DOI: 10.1021/jacs.9b09016] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Seventeen Cu complexes with formal oxidation states ranging from CuI to CuIII are investigated through the use of multiedge X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations. Analysis reveals that the metal-ligand bonding in high-valent, formally CuIII species is extremely covalent, resulting in Cu K-edge and L2,3-edge spectra whose features have energies that complicate physical oxidation state assignment. Covalency analysis of the Cu L2,3-edge data reveals that all formally CuIII species have significantly diminished Cu d-character in their lowest unoccupied molecular orbitals (LUMOs). DFT calculations provide further validation of the orbital composition analysis, and excellent agreement is found between the calculated and experimental results. The finding that Cu has limited capacity to be oxidized necessitates localization of electron hole character on the supporting ligands; consequently, the physical d8 description for these formally CuIII species is inaccurate. This study provides an alternative explanation for the competence of formally CuIII species in transformations that are traditionally described as metal-centered, 2-electron CuI/CuIII redox processes.
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Affiliation(s)
- Ida M. DiMucci
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, New York 14853, United States
| | - James T. Lukens
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, New York 14853, United States
| | - Sudipta Chatterjee
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, New York 14853, United States
| | - Kurtis M. Carsch
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Charles J. Titus
- Department of Physics, Stanford University, Stanford, California 94305, United States
| | - Sang Jun Lee
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Dennis Nordlund
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Theodore A. Betley
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Samantha N. MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, New York 14853, United States
| | - Kyle M. Lancaster
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, New York 14853, United States
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Photocatalytic regio- and stereoselective C(sp3)–H functionalization of benzylic and allylic hydrocarbons as well as unactivated alkanes. Nat Catal 2019. [DOI: 10.1038/s41929-019-0357-9] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Zhang Y, Zhang S, Sun Z, He K, Chen Q, Yuan Y, Jia X. C–N Bond Activation of N,N′-Dialkylacylhydrazines Mediated by β-Fragmentation of Nitrogen-Centered Radical. J Org Chem 2019; 84:14202-14208. [DOI: 10.1021/acs.joc.9b01851] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Yuxian Zhang
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, China
| | - Shuwei Zhang
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, China
| | - Zheng Sun
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, China
| | - Kaixuan He
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, China
| | - Qian Chen
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, China
| | - Yu Yuan
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, China
| | - Xiaodong Jia
- School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, China
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A Comparative Study of the Catalytic Behaviour of Alkoxy-1,3,5-Triazapentadiene Copper(II) Complexes in Cyclohexane Oxidation. INORGANICS 2019. [DOI: 10.3390/inorganics7070082] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The mononuclear copper complexes [Cu{NH=C(OR)NC(OR)=NH}2] with alkoxy-1,3,5-triazapentadiene ligands that have different substituents (R = Me (1), Et (2), nPr (3), iPr (4), CH2CH2OCH3 (5)) were prepared, characterized (including the single crystal X-ray analysis of 3) and studied as catalysts in the mild oxidation of alkanes with H2O2 as an oxidant, pyridine as a promoting agent and cyclohexane as a main model substrate. The complex 4 showed the highest activity with a yield of products up to 18.5% and turnover frequency (TOF) up to 41 h−1. Cyclohexyl hydroperoxide was the main reaction product in all cases. Selectivity parameters in the oxidation of substituted cyclohexanes and adamantane disclosed a dominant free radical reaction mechanism with hydroxyl radicals as C–H-attacking species. The main overoxidation product was 6-hydroxyhexanoic acid, suggesting the presence of a secondary reaction mechanism of a different type. All complexes undergo gradual alteration of their structures in acetonitrile solutions to produce catalytically-active intermediates, as evidenced by UV/Vis spectroscopy and kinetic studies. Complex 4, having tertiary C–H bonds in its iPr substituents, showed the fastest alteration rate, which can be significantly suppressed by using the CD3CN solvent instead of CH3CN one. The observed process was associated to an autocatalytic oxidation of the alkoxy-1,3,5-triazapentadiene ligand. The deuterated complex 4-d32 was prepared and showed higher stability under the same conditions. The complexes 1 and 4 showed different reactivity in the formation of H218O from 18O2 in acetonitrile solutions.
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