1
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Kulathungage LW, Kurup SS, Browne EA, Spalink GH, Ward CL, Lord RL, Groysman S. Efficient carbene transfer reactivity mediated by Fe(II) complexes supported by bulky alkoxides. Chem Commun (Camb) 2024; 60:7033-7036. [PMID: 38896088 PMCID: PMC11372682 DOI: 10.1039/d4cc02108h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Herein we describe the stoichiometric and catalytic carbene-transfer reactivity of iron(II) alkoxide complexes with iodonium ylide precursors. Treatment of PhIC(CO2Me)2 with styrene in the presence of catalytic amounts of several different Fe(OR)2(THF)2 precursors results in efficient cyclopropanation for a variety of styrenes. Computational and reactivity studies suggest a novel remote metallocarbene/vinyl radical intermediate, Fe(OR)2(κ2-(OC(OMe))2C), which could be responsible for the reactive nature of the catalyst.
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Affiliation(s)
| | - Sudheer S Kurup
- Department of Chemistry, Wayne State University, 5101 Cass Ave., Detroit, MI 48202, USA.
| | - Edison A Browne
- Department of Chemistry, Grand Valley State University, 1 Campus Dr, Allendale, MI 49401, USA.
| | - Gabriel H Spalink
- Department of Chemistry, Grand Valley State University, 1 Campus Dr, Allendale, MI 49401, USA.
| | - Cassandra L Ward
- Lumigen Instrument Center, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, USA
| | - Richard L Lord
- Department of Chemistry, Grand Valley State University, 1 Campus Dr, Allendale, MI 49401, USA.
| | - Stanislav Groysman
- Department of Chemistry, Wayne State University, 5101 Cass Ave., Detroit, MI 48202, USA.
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2
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Epping RF, Vesseur D, Zhou M, de Bruin B. Carbene Radicals in Transition-Metal-Catalyzed Reactions. ACS Catal 2023; 13:5428-5448. [PMID: 37123600 PMCID: PMC10127290 DOI: 10.1021/acscatal.3c00591] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/21/2023] [Indexed: 04/08/2023]
Abstract
Discovered as organometallic curiosities in the 1970s, carbene radicals have become a staple in modern-day homogeneous catalysis. Carbene radicals exhibit nucleophilic radical-type reactivity orthogonal to classical electrophilic diamagnetic Fischer carbenes. Their successful catalytic application has led to the synthesis of a myriad of carbo- and heterocycles, ranging from simple cyclopropanes to more challenging eight-membered rings. The field has matured to employ densely functionalized chiral porphyrin-based platforms that exhibit high enantio-, regio-, and stereoselectivity. Thus far the focus has largely been on cobalt-based systems, but interest has been growing for the past few years to expand the application of carbene radicals to other transition metals. This Perspective covers the advances made since 2011 and gives an overview on the coordination chemistry, reactivity, and catalytic application of carbene radical species using transition metal complexes and catalysts.
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Affiliation(s)
- Roel F.J. Epping
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - David Vesseur
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Minghui Zhou
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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3
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Wang C, Yang L. An Efficient Solvent-free Synthesis of Spiro-substituted Cyclopropanes by Grinding. ORG PREP PROCED INT 2022. [DOI: 10.1080/00304948.2022.2141042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Changqing Wang
- College of Chemistry and Chemical Engineering, Jiujiang University, Jiujiang, China
- Jiangxi Province Engineering Research Center of Ecological Chemical Industry, Jiujiang University, Jiujiang, China
| | - Liu Yang
- College of Chemistry and Chemical Engineering, Jiujiang University, Jiujiang, China
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4
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Affiliation(s)
- Wan-Chen Cindy Lee
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA
| | - X. Peter Zhang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA
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5
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Cobalt(II)-tetraphenylporphyrin-catalysed carbene transfer from acceptor-acceptor iodonium ylides via N-enolate-carbene radicals. Nat Chem 2022; 14:550-557. [PMID: 35332284 DOI: 10.1038/s41557-022-00905-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 02/02/2022] [Indexed: 12/17/2022]
Abstract
Square-planar cobalt(II) systems have emerged as powerful carbene transfer catalysts for the synthesis of numerous (hetero)cyclic compounds via cobalt(III)-carbene radical intermediates. Spectroscopic detection and characterization of reactive carbene radical intermediates is limited to a few scattered experiments, centered around monosubstituted carbenes. Here, we reveal the formation of disubstituted cobalt(III)-carbene radicals derived from a cobalt(II)-tetraphenylporphyrin complex and acceptor-acceptor λ3-iodaneylidenes (iodonium ylides) as carbene precursors and their catalytic application. Iodonium ylides generate biscarbenoid species via reversible ligand modification of the paramagnetic cobalt(II)-tetraphenylporphyrin complex catalyst. Two interconnected catalytic cycles are involved in the overall mechanism, with a monocarbene radical and an N-enolate-carbene radical intermediate at the heart of each respective cycle. Notably, N-enolate formation is not a deactivation pathway but a reversible process, enabling transfer of two carbene moieties from a single N-enolate-carbene radical intermediate. The findings are supported by extensive experimental and computational studies.
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6
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Planas F, Costantini M, Montesinos-Magraner M, Himo F, Mendoza A. Combined Experimental and Computational Study of Ruthenium N-Hydroxyphthalimidoyl Carbenes in Alkene Cyclopropanation Reactions. ACS Catal 2021; 11:10950-10963. [PMID: 34504736 PMCID: PMC8419840 DOI: 10.1021/acscatal.1c02540] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 08/05/2021] [Indexed: 01/14/2023]
Abstract
A combined experimental-computational approach has been used to study the cyclopropanation reaction of N-hydroxyphthalimide diazoacetate (NHPI-DA) with various olefins, catalyzed by a ruthenium-phenyloxazoline (Ru-Pheox) complex. Kinetic studies show that the better selectivity of the employed redox-active NHPI diazoacetate is a result of a much slower dimerization reaction compared to aliphatic diazoacetates. Density functional theory calculations reveal that several reactions can take place with similar energy barriers, namely, dimerization of the NHPI diazoacetate, cyclopropanation (inner-sphere and outer-sphere), and a previously unrecognized migratory insertion of the carbene into the phenyloxazoline ligand. The calculations show that the migratory insertion reaction yields an unconsidered ruthenium complex that is catalytically competent for both the dimerization and cyclopropanation, and its relevance is assessed experimentally. The stereoselectivity of the reaction is argued to stem from an intricate balance between the various mechanistic scenarios.
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Affiliation(s)
| | | | - Marc Montesinos-Magraner
- Department of Organic Chemistry,
Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Fahmi Himo
- Department of Organic Chemistry,
Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Abraham Mendoza
- Department of Organic Chemistry,
Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
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7
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Mouarrawis V, Bobylev EO, de Bruin B, Reek JNH. A Novel M 8 L 6 Cubic Cage That Binds Tetrapyridyl Porphyrins: Cage and Solvent Effects in Cobalt-Porphyrin-Catalyzed Cyclopropanation Reactions. Chemistry 2021; 27:8390-8397. [PMID: 33780040 PMCID: PMC8252039 DOI: 10.1002/chem.202100344] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Indexed: 12/17/2022]
Abstract
Confinement of a catalyst can have a significant impact on catalytic performance and can lead to otherwise difficult to achieve catalyst properties. Herein, we report the design and synthesis of a novel caged catalyst system Co-G@Fe8 (Zn-L ⋅ 1)6 , which is soluble in both polar and apolar solvents without the necessity of any post-functionalization. This is a rare example of a metal-coordination cage able to bind catalytically active porphyrins that is soluble in solvents spanning a wide variety of polarity. This system was used to investigate the combined effects of the solvent and the cage on the catalytic performance in the cobalt catalyzed cyclopropanation of styrene, which involves radical intermediates. Kinetic studies show that DMF has a protective influence on the catalyst, slowing down deactivation of both [Co(TPP)] and Co-G@Fe8 (Zn-L ⋅ 1)6 , leading to higher TONs in this solvent. Moreover, DFT studies on the [Co(TPP)] catalyst show that the rate determining energy barrier of this radical-type transformation is not influenced by the coordination of DMF. As such, the increased TONs obtained experimentally stem from the stabilizing effect of DMF and are not due to an intrinsic higher activity caused by axial ligand binding to the cobalt center ([Co(TPP)(L)]). Remarkably, encapsulation of Co-G led to a three times more active catalyst than [Co(TPP)] (TOFini ) and a substantially increased TON compared to both [Co(TPP)] and free Co-G. The increased local concentration of the substrates in the hydrophobic cage compared to the bulk explains the observed higher catalytic activities.
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Affiliation(s)
- Valentinos Mouarrawis
- Homogeneous and Supramolecular Catalysis Group, Van' t Hoff Institute for Molecular Science (HIMS), University of Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Eduard O Bobylev
- Homogeneous and Supramolecular Catalysis Group, Van' t Hoff Institute for Molecular Science (HIMS), University of Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous and Supramolecular Catalysis Group, Van' t Hoff Institute for Molecular Science (HIMS), University of Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Joost N H Reek
- Homogeneous and Supramolecular Catalysis Group, Van' t Hoff Institute for Molecular Science (HIMS), University of Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
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8
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Silva LDSD, Souza AAD, Sá É. Computational considerations on the mechanism and stereoselectivity in cyclopropanation reactions via iron-carbenes. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2021.153023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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9
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Hessels J, Masferrer‐Rius E, Yu F, Detz RJ, Klein Gebbink RJM, Reek JNH. Nickel is a Different Pickle: Trends in Water Oxidation Catalysis for Molecular Nickel Complexes. CHEMSUSCHEM 2020; 13:6629-6634. [PMID: 33090703 PMCID: PMC7756549 DOI: 10.1002/cssc.202002164] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Indexed: 06/11/2023]
Abstract
The development of novel water oxidation catalysts is important in the context of renewable fuels production. Ligand design is one of the key tools to improve the activity and stability of molecular catalysts. The establishment of ligand design rules can facilitate the development of improved molecular catalysts. In this paper it is shown that chemical oxidants can be used to probe oxygen evolution activity for nickel-based systems, and trends are reported that can improve future ligand design. Interestingly, different ligand effects were observed in comparison to other first-row transition metal complexes. For example, nickel complexes with secondary amine donors were more active than with tertiary amine donors, which is the opposite for iron complexes. The incorporation of imine donor groups in a cyclam ligand resulted in the fastest and most durable nickel catalyst of our series, achieving oxygen evolution turnover numbers up to 380 and turnover frequencies up to 68 min-1 in a pH 5.0 acetate buffer using Oxone as oxidant. Initial kinetic experiments with this catalyst revealed a first order in chemical oxidant and a half order in catalyst. This implies a rate-determining oxidation step from a dimeric species that needs to break up to generate the active catalyst. These findings lay the foundation for the rational design of molecular nickel catalysts for water oxidation and highlight that catalyst design rules are not generally applicable for different metals.
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Affiliation(s)
- Joeri Hessels
- Homogeneous, Supramolecular and Bio-Inspired Catalysis, Van ‘t Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098 XHAmsterdamThe Netherlands
| | - Eduard Masferrer‐Rius
- Organic Chemistry & Catalysis, Debye Institute for Nanomaterials ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Fengshou Yu
- Homogeneous, Supramolecular and Bio-Inspired Catalysis, Van ‘t Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098 XHAmsterdamThe Netherlands
| | - Remko J. Detz
- Current address: TNO Energy Transition, Energy Transition StudiesRadarweg 601043 NTAmsterdamThe Netherlands
| | - Robertus J. M. Klein Gebbink
- Organic Chemistry & Catalysis, Debye Institute for Nanomaterials ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Joost N. H. Reek
- Homogeneous, Supramolecular and Bio-Inspired Catalysis, Van ‘t Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098 XHAmsterdamThe Netherlands
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10
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Alcântara AFP, Fontana LA, Almeida MP, Rigolin VH, Ribeiro MA, Barros WP, Megiatto JD. Control over the Redox Cooperative Mechanism of Radical Carbene Transfer Reactions for the Efficient Active‐Metal‐Template Synthesis of [2]Rotaxanes. Chemistry 2020; 26:7808-7822. [DOI: 10.1002/chem.201905602] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Indexed: 02/01/2023]
Affiliation(s)
- Arthur F. P. Alcântara
- Institute of ChemistryUniversity of Campinas (UNICAMP) PO Box 6154 13083-970 Campinas Brazil
- Instituto Federal do Sertão Pernambucano Estrada do Tamboril 56200-000 Ouricuri Brazil
| | - Liniquer A. Fontana
- Institute of ChemistryUniversity of Campinas (UNICAMP) PO Box 6154 13083-970 Campinas Brazil
| | - Marlon P. Almeida
- Institute of ChemistryUniversity of Campinas (UNICAMP) PO Box 6154 13083-970 Campinas Brazil
| | - Vitor H. Rigolin
- Institute of ChemistryUniversity of Campinas (UNICAMP) PO Box 6154 13083-970 Campinas Brazil
| | - Marcos A. Ribeiro
- Departamento de QuímicaUniversidade Federal do Espírito Santo Av. Fernando Ferrari, 514 29075-910 Vitória Brazil
| | - Wdeson P. Barros
- Institute of ChemistryUniversity of Campinas (UNICAMP) PO Box 6154 13083-970 Campinas Brazil
| | - Jackson D. Megiatto
- Institute of ChemistryUniversity of Campinas (UNICAMP) PO Box 6154 13083-970 Campinas Brazil
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11
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van Vliet KM, van Leeuwen NS, Brouwer AM, de Bruin B. Visible-light-induced addition of carboxymethanide to styrene from monochloroacetic acid. Beilstein J Org Chem 2020; 16:398-408. [PMID: 32273903 PMCID: PMC7113555 DOI: 10.3762/bjoc.16.38] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 03/05/2020] [Indexed: 11/23/2022] Open
Abstract
Where monochloroacetic acid is widely used as a starting material for the synthesis of relevant groups of compounds, many of these synthetic procedures are based on nucleophilic substitution of the carbon chlorine bond. Oxidative or reductive activation of monochloroacetic acid results in radical intermediates, leading to reactivity different from the traditional reactivity of this compound. Here, we investigated the possibility of applying monochloroacetic acid as a substrate for photoredox catalysis with styrene to directly produce γ-phenyl-γ-butyrolactone. Instead of using nucleophilic substitution, we cleaved the carbon chlorine bond by single-electron reduction, creating a radical species. We observed that the reaction works best in nonpolar solvents. The reaction does not go to full conversion, but selectively forms γ-phenyl-γ-butyrolactone and 4-chloro-4-phenylbutanoic acid. Over time the catalyst precipitates from solution (perhaps in a decomposed form in case of fac-[Ir(ppy)3]), which was proven by mass spectrometry and EPR spectroscopy for one of the catalysts (N,N-5,10-di(2-naphthalene)-5,10-dihydrophenazine) used in this work. The generation of HCl resulting from lactone formation could be an additional problem for organometallic photoredox catalysts used in this reaction. In an attempt to trap one of the radical intermediates with TEMPO, we observed a compound indicating the generation of a chloromethyl radical.
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Affiliation(s)
- Kaj M van Vliet
- Van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
| | - Nicole S van Leeuwen
- Van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
| | - Albert M Brouwer
- Van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
| | - Bas de Bruin
- Van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
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12
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Michiyuki T, Komeyama K. Recent Advances in Four‐Coordinated Planar Cobalt Catalysis in Organic Synthesis. ASIAN J ORG CHEM 2019. [DOI: 10.1002/ajoc.201900625] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Takuya Michiyuki
- Department of Applied ChemistryGraduate School of EngineeringHiroshima University 1-4-1 Kagamiyama, Higashi-Hiroshima Hiroshima 739-8527 Japan
| | - Kimihiro Komeyama
- Department of Applied ChemistryGraduate School of EngineeringHiroshima University 1-4-1 Kagamiyama, Higashi-Hiroshima Hiroshima 739-8527 Japan
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13
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Herndon JW. The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2018. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2019.213051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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14
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van Vliet KM, Polak LH, Siegler MA, van der Vlugt JI, Guerra CF, de Bruin B. Efficient Copper-Catalyzed Multicomponent Synthesis of N-Acyl Amidines via Acyl Nitrenes. J Am Chem Soc 2019; 141:15240-15249. [PMID: 31465210 PMCID: PMC6764152 DOI: 10.1021/jacs.9b07140] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
![]()
Direct
synthetic routes to amidines are desired, as they are widely
present in many biologically active compounds and organometallic complexes. N-Acyl amidines in particular can be used as a starting
material for the synthesis of heterocycles and have several other
applications. Here, we describe a fast and practical copper-catalyzed
three-component reaction of aryl acetylenes, amines, and easily accessible
1,4,2-dioxazol-5-ones to N-acyl amidines, generating
CO2 as the only byproduct. Transformation of the dioxazolones
on the Cu catalyst generates acyl nitrenes that rapidly insert into
the copper acetylide Cu–C bond rather than undergoing an undesired
Curtius rearrangement. For nonaromatic dioxazolones, [Cu(OAc)(Xantphos)]
is a superior catalyst for this transformation, leading to full substrate
conversion within 10 min. For the direct synthesis of N-benzoyl amidine derivatives from aromatic dioxazolones, [Cu(OAc)(Xantphos)]
proved to be inactive, but moderate to good yields were obtained when
using simple copper(I) iodide (CuI) as the catalyst. Mechanistic studies
revealed the aerobic instability of one of the intermediates at low
catalyst loadings, but the reaction could still be performed in air
for most substrates when using catalyst loadings of 5 mol %. The herein
reported procedure not only provides a new, practical, and direct
route to N-acyl amidines but also represents a new
type of C–N bond formation.
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Affiliation(s)
- Kaj M van Vliet
- Homogeneous, Supramolecular and Bio-inspired Catalysis Group (HomKat), van 't Hoff Institute for Molecular Sciences (HIMS) , Universiteit van Amsterdam (UvA) , Amsterdam 1012 WX , The Netherlands
| | - Lara H Polak
- Homogeneous, Supramolecular and Bio-inspired Catalysis Group (HomKat), van 't Hoff Institute for Molecular Sciences (HIMS) , Universiteit van Amsterdam (UvA) , Amsterdam 1012 WX , The Netherlands
| | - Maxime A Siegler
- Department of Chemistry , John Hopkins University , Baltimore , Maryland 21218 , United States
| | - Jarl Ivar van der Vlugt
- Homogeneous, Supramolecular and Bio-inspired Catalysis Group (HomKat), van 't Hoff Institute for Molecular Sciences (HIMS) , Universiteit van Amsterdam (UvA) , Amsterdam 1012 WX , The Netherlands
| | - Célia Fonseca Guerra
- Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling , Vrije Universiteit Amsterdam (VU) , De Boelelaan 1083 , 1081 HV Amsterdam , The Netherlands.,Leiden Institute of Chemistry, Gorlaeus Laboratories , Úniversiteit Leiden , Einsteinweg 55 , 2333 CC Leiden , The Netherlands
| | - Bas de Bruin
- Homogeneous, Supramolecular and Bio-inspired Catalysis Group (HomKat), van 't Hoff Institute for Molecular Sciences (HIMS) , Universiteit van Amsterdam (UvA) , Amsterdam 1012 WX , The Netherlands
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15
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Heins SP, Zhang B, MacMillan SN, Cundari TR, Wolczanski PT. Oxidative Additions to Ti(IV) in [(dadi)4–]TiIV(THF) Involve Carbon–Carbon Bond Formation and Redox-Noninnocent Behavior. Organometallics 2019. [DOI: 10.1021/acs.organomet.8b00930] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Spencer P. Heins
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Bufan Zhang
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Samantha N. MacMillan
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Thomas R. Cundari
- Department of Chemistry, CASCaM, University of North Texas, Denton, Texas 76201, United States
| | - Peter T. Wolczanski
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
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16
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Dey S, Wayland BB, Zdilla MJ. Solution and Solid State Properties for Low-Spin Cobalt(II) Dibenzotetramethyltetraaza[14]annulene [(tmtaa)Co II] and the Monopyridine Complex. Inorg Chem 2019; 58:1224-1233. [PMID: 30618250 DOI: 10.1021/acs.inorgchem.8b02644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The single-crystal X-ray structure of solvent-free (tmtaa)CoII reveals three different π-π intermacrocyclic interactions between tmtaa units (tmtaa = dibenzotetramethyltetraaza[14]annulene). Pairs of inequivalent (tmtaa)CoII units in the unit cell link into a one-dimensional π-π stacked array in the solid state. Magnetic susceptibility (χ) studies from 300 to 2 K reveal the effects of intermolecular interactions between (tmtaa)CoII units in the solid state. The effective magnetic moment per CoII center is constant at 2.83 μB from 300 to 100 K and begins to significantly decrease at lower temperatures. The magnetic data are fit to a singlet ( S = 0) ground state with a triplet ( S = 1) excited state that is 13 cm-1 higher in energy (-2 J = 13 cm-1). Toluene solutions of (tmtaa)CoII have 1H nuclear magnetic resonance (NMR) paramagnetic shifts, a solution-phase magnetic moment μeff (295 K) of 2.1 μB, and toluene glass electron paramagnetic resonance spectra that are most consistent with a low-spin ( S = 1/2) CoII with the unpaired electron located in the d yz orbital. Pyridine interacts with (tmtaa)CoII to form a five-coordinate monopyridine complex in which the unpaired electron is in the d z2 orbital. The five-coordinate complex has been structurally characterized by single-crystal X-ray diffraction, and the equilibrium constant for pyridine binding at 295 K has been evaluated by both electronic and 1H NMR spectra. Density functional theory computation using the UB3LYP hybrid functional places the unpaired electron for (tmtaa)CoII in the d yz orbital and that for the monopyridine complex in the d z2 orbital, consistent with spectroscopic observations.
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Affiliation(s)
- Soumyajit Dey
- Department of Chemistry , Temple University , 1901 Northy 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Bradford B Wayland
- Department of Chemistry , Temple University , 1901 Northy 13th Street , Philadelphia , Pennsylvania 19122 , United States
| | - Michael J Zdilla
- Department of Chemistry , Temple University , 1901 Northy 13th Street , Philadelphia , Pennsylvania 19122 , United States
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