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Yoshimura A, Zhdankin VV. Recent Progress in Synthetic Applications of Hypervalent Iodine(III) Reagents. Chem Rev 2024. [PMID: 39269928 DOI: 10.1021/acs.chemrev.4c00303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2024]
Abstract
Hypervalent iodine(III) compounds have found wide application in modern organic chemistry as environmentally friendly reagents and catalysts. Hypervalent iodine reagents are commonly used in synthetically important halogenations, oxidations, aminations, heterocyclizations, and various oxidative functionalizations of organic substrates. Iodonium salts are important arylating reagents, while iodonium ylides and imides are excellent carbene and nitrene precursors. Various derivatives of benziodoxoles, such as azidobenziodoxoles, trifluoromethylbenziodoxoles, alkynylbenziodoxoles, and alkenylbenziodoxoles have found wide application as group transfer reagents in the presence of transition metal catalysts, under metal-free conditions, or using photocatalysts under photoirradiation conditions. Development of hypervalent iodine catalytic systems and discovery of highly enantioselective reactions using chiral hypervalent iodine compounds represent a particularly important recent achievement in the field of hypervalent iodine chemistry. Chemical transformations promoted by hypervalent iodine in many cases are unique and cannot be performed by using any other common, non-iodine-based reagent. This review covers literature published mainly in the last 7-8 years, between 2016 and 2024.
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Affiliation(s)
- Akira Yoshimura
- Faculty of Pharmaceutical Sciences, Aomori University, 2-3-1 Kobata, Aomori 030-0943, Japan
| | - Viktor V Zhdankin
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, United States
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2
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Parker GL, Van Lommel R, Roig N, Alonso M, Chaplin AB. Modulation of Metal Carbonyl Stretching Frequencies in the Second Coordination Sphere through the Internal Stark Effect. Chemistry 2022; 28:e202202283. [PMID: 36082961 PMCID: PMC10092048 DOI: 10.1002/chem.202202283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Indexed: 12/14/2022]
Abstract
Spectroscopic and computational examination of a homologous series of rhodium(I) pybox carbonyl complexes has revealed a correlation between the conformation of the flanking aryl-substituted oxazoline donors and the carbonyl stretching frequency. This relationship is also observed experimentally for octahedral rhodium(III) and ruthenium(II) variants and cannot be explained through the classical, Dewar-Chatt-Duncanson, interpretation of metal-carbonyl bonding. Instead, these findings are reconciled by local changes in the magnitude of the electric field that is projected along the metal-carbonyl vector: the internal Stark effect.
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Affiliation(s)
- Gemma L. Parker
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCV4 7ALCoventryUK
| | - Ruben Van Lommel
- Eenheid Algemene Chemie (ALGC)Vrije Universiteit Brussel (VUB)1050BrusselsBelgium
- Molecular Design and SynthesisDepartment of ChemistryKU Leuven3001LeuvenBelgium
| | - Nil Roig
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCV4 7ALCoventryUK
- Eenheid Algemene Chemie (ALGC)Vrije Universiteit Brussel (VUB)1050BrusselsBelgium
| | - Mercedes Alonso
- Eenheid Algemene Chemie (ALGC)Vrije Universiteit Brussel (VUB)1050BrusselsBelgium
| | - Adrian B. Chaplin
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCV4 7ALCoventryUK
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Cobalt(I) Pincer Complexes: Four‐ versus Five‐coordination. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200267] [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]
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Mohammadnezhad G, Amirian AM, Görls H, Plass W, Sandleben A, Schäfer S, Klein A. Redox Instability of Copper(II) Complexes of a Triazine‐Based PNP Pincer. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202001129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
| | - Ali Mohammad Amirian
- Department of Chemistry Isfahan University of Technology Isfahan 84156-83111 Iran
- Chemistry Department Faculty of Science Shiraz University Shiraz 71454 Iran
| | - Helmar Görls
- Lehrstuhl für Anorganische Chemie II Institut für Anorganische und Analytische Chemie Friedrich-Schiller-Universität Jena Humboldtstr. 8 07743 Jena Germany
| | - Winfried Plass
- Lehrstuhl für Anorganische Chemie II Institut für Anorganische und Analytische Chemie Friedrich-Schiller-Universität Jena Humboldtstr. 8 07743 Jena Germany
| | - Aaron Sandleben
- Department für Chemie Institut für Anorganische Chemie Universität zu Köln Greinstraße 6 50939 Köln Germany
| | - Sascha Schäfer
- Department für Chemie Institut für Anorganische Chemie Universität zu Köln Greinstraße 6 50939 Köln Germany
| | - Axel Klein
- Chemistry Department Faculty of Science Shiraz University Shiraz 71454 Iran
- Department für Chemie Institut für Anorganische Chemie Universität zu Köln Greinstraße 6 50939 Köln Germany
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Hood TM, Chaplin AB. Synthesis and reactivity of iridium complexes of a macrocyclic PNP pincer ligand. Dalton Trans 2021; 50:2472-2482. [PMID: 33511383 DOI: 10.1039/d0dt04303f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Having recently reported on the synthesis and rhodium complexes of the novel macrocyclic pincer ligand PNP-14, which is derived from lutidine and features terminal phosphine donors trans-substituted with a tetradecamethylene linker (Dalton Trans., 2020, 49, 2077-2086 and Dalton Trans., 2020, 49, 16649-16652), we herein describe our findings critically examining the chemistry of iridium homologues. The five-coordinate iridium(i) and iridium(iii) complexes [Ir(PNP-14)(η2:η2-cyclooctadiene)][BArF4] and [Ir(PNP-14)(2,2'-biphenyl)][BArF4] are readily prepared and shown to be effective precursors for the generation of iridium(iii) dihydride dihydrogen, iridium(i) bis(ethylene), and iridium(i) carbonyl derivatives that highlight important periodic trends by comparison to rhodium counterparts. Reaction of [Ir(PNP-14)H2(H2)][BArF4] with 3,3-dimethylbutene induced triple C-H bond activation of the methylene chain, yielding an iridium(iii) allyl hydride derivative [Ir(PNP-14*)H][BArF4], whilst catalytic homocoupling of 3,3-dimethylbutyne into Z-tBuC[triple bond, length as m-dash]CCHCHtBu could be promoted at RT by [Ir(PNP-14)(η2:η2-cyclooctadiene)][BArF4] (TOFinitial = 28 h-1). The mechanism of the latter is proposed to involve formation and direct reaction of a vinylidene derivative with HC[triple bond, length as m-dash]CtBu outside of the macrocyclic ring and this suggestion is supported experimentally by isolation and crystallographic characterisation of a catalyst deactivation product.
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Affiliation(s)
- Thomas M Hood
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
| | - Adrian B Chaplin
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
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Johnson A, Royle CG, Brodie CN, Martínez-Martínez AJ, Duckett SB, Weller AS. η 2-Alkene Complexes of [Rh(PONOP- iPr)(L)] + Cations (L = COD, NBD, Ethene). Intramolecular Alkene-Assisted Hydrogenation and Dihydrogen Complex [Rh(PONOP- iPr)(η-H 2)] . Inorg Chem 2021; 60:13903-13912. [PMID: 33570930 PMCID: PMC8456414 DOI: 10.1021/acs.inorgchem.0c03687] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Rhodium-alkene complexes of the pincer ligand κ3-C5H3N-2,6-(OPiPr2)2 (PONOP-iPr) have been prepared and structurally characterized: [Rh(PONOP-iPr)(η2-alkene)][BArF4] [alkene = cyclooctadiene (COD), norbornadiene (NBD), ethene; ArF = 3,5-(CF3)2C6H3]. Only one of these, alkene = COD, undergoes a reaction with H2 (1 bar), to form [Rh(PONOP-iPr)(η2-COE)][BArF4] (COE = cyclooctene), while the others show no significant reactivity. This COE complex does not undergo further hydrogenation. This difference in reactivity between COD and the other alkenes is proposed to be due to intramolecular alkene-assisted reductive elimination in the COD complex, in which the η2-bound diene can engage in bonding with its additional alkene unit. H/D exchange experiments on the ethene complex show that reductive elimination from a reversibly formed alkyl hydride intermediate is likely rate-limiting and with a high barrier. The proposed final product of alkene hydrogenation would be the dihydrogen complex [Rh(PONOP-iPr)(η2-H2)][BArF4], which has been independently synthesized and undergoes exchange with free H2 on the NMR time scale, as well as with D2 to form free HD. When the H2 addition to [Rh(PONOP-iPr)(η2-ethene)][BArF4] is interrogated using pH2 at higher pressure (3 bar), this produces the dihydrogen complex as a transient product, for which enhancements in the 1H NMR signal for the bound H2 ligand, as well as that for free H2, are observed. This is a unique example of the partially negative line-shape effect, with the enhanced signals that are observed for the dihydrogen complex being explained by the exchange processes already noted.
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Affiliation(s)
- Alice Johnson
- Chemical Research Laboratories, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Cameron G Royle
- Chemical Research Laboratories, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K.,Department of Chemistry, University of York, York YO10 5DD, U.K
| | - Claire N Brodie
- Department of Chemistry, University of York, York YO10 5DD, U.K
| | | | - Simon B Duckett
- Department of Chemistry, University of York, York YO10 5DD, U.K
| | - Andrew S Weller
- Department of Chemistry, University of York, York YO10 5DD, U.K
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Storey CM, Gyton MR, Andrew RE, Chaplin AB. Terminal Alkyne Coupling Reactions Through a Ring: Effect of Ring Size on Rate and Regioselectivity. Chemistry 2020; 26:14715-14723. [PMID: 32677713 PMCID: PMC7756505 DOI: 10.1002/chem.202002962] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 07/15/2020] [Indexed: 01/11/2023]
Abstract
Terminal alkyne coupling reactions promoted by rhodium(I) complexes of macrocyclic NHC-based pincer ligands-which feature dodecamethylene, tetradecamethylene or hexadecamethylene wingtip linkers viz. [Rh(CNC-n)(C2 H4 )][BArF 4 ] (n=12, 14, 16; ArF =3,5-(CF3 )2 C6 H3 )-have been investigated, using the bulky alkynes HC≡CtBu and HC≡CAr' (Ar'=3,5-tBu2 C6 H3 ) as substrates. These stoichiometric reactions proceed with formation of rhodium(III) alkynyl alkenyl derivatives and produce rhodium(I) complexes of conjugated 1,3-enynes by C-C bond reductive elimination through the annulus of the ancillary ligand. The intermediates are formed with orthogonal regioselectivity, with E-alkenyl complexes derived from HC≡CtBu and gem-alkenyl complexes derived from HC≡CAr', and the reductive elimination step is appreciably affected by the ring size of the macrocycle. For the homocoupling of HC≡CtBu, E-tBuC≡CCH=CHtBu is produced via direct reductive elimination from the corresponding rhodium(III) alkynyl E-alkenyl derivatives with increasing efficacy as the ring is expanded. In contrast, direct reductive elimination of Ar'C≡CC(=CH2 )Ar' is encumbered relative to head-to-head coupling of HC≡CAr' and it is only with the largest macrocyclic ligand studied that the two processes are competitive. These results showcase how macrocyclic ligands can be used to interrogate the mechanism and tune the outcome of terminal alkyne coupling reactions, and are discussed with reference to catalytic reactions mediated by the acyclic homologue [Rh(CNC-Me)(C2 H4 )][BArF 4 ] and solvent effects.
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Affiliation(s)
- Caroline M. Storey
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
| | - Matthew R. Gyton
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
| | - Rhiann E. Andrew
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
| | - Adrian B. Chaplin
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
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Kynman AE, Lau S, Dowd SO, Krämer T, Chaplin AB. Oxidative Addition of Biphenylene and Chlorobenzene to a Rh(CNC) Complex. Eur J Inorg Chem 2020; 2020:3899-3906. [PMID: 33328794 PMCID: PMC7702176 DOI: 10.1002/ejic.202000780] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Indexed: 01/10/2023]
Abstract
The synthesis and organometallic chemistry of rhodium(I) complex [Rh(CNC-Me)(SOMe2)][BArF 4], featuring NHC-based pincer and labile dimethyl sulfoxide ligands, is reported. This complex reacts with biphenylene and chlorobenzene to afford products resulting from selective C-C and C-Cl bond activation, [Rh(CNC-Me)(2,2'-biphenyl)(OSMe2)][BArF 4] and [Rh(CNC-Me)(Ph)Cl(OSMe2)][BArF 4], respectively. A detailed DFT-based computational analysis indicates that C-H bond oxidative addition of these substrates is kinetically competitive, but in all cases endergonic: contrasting the large thermodynamic driving force calculated for insertion of the metal into the C-C and C-Cl bonds, respectively. Under equivalent conditions the substrates are not activated by the phosphine-based pincer complex [Rh(PNP-iPr)(SOMe2)][BArF 4].
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Affiliation(s)
- Amy E. Kynman
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
| | - Samantha Lau
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
| | - Sean O. Dowd
- Department of ChemistryMaynooth UniversityCo. KildareMaynoothIreland
| | - Tobias Krämer
- Department of ChemistryMaynooth UniversityCo. KildareMaynoothIreland
- Hamilton InstituteMaynooth UniversityCo. KildareMaynoothIreland
| | - Adrian B. Chaplin
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
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Chapp SM, Schley ND. Group-Transfer Reactions of a Cationic Iridium Alkoxycarbene Generated by Ether Dehydrogenation. Inorg Chem 2020; 59:7143-7149. [PMID: 32330012 DOI: 10.1021/acs.inorgchem.0c00609] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Despite broad interest in metal carbene complexes, there remain few examples of catalytic transformations of ethers that proceed via alkoxycarbene intermediates generated by α,α-dehydrogenation. We demonstrate that both neutral and cationic alkoxycarbene derivatives are accessible via ether dehydrogenation at a PNP(iPr)4 pincer-supported iridium complex (PNP(iPr)4 = 2,6-bis((diisopropylphosphino)methyl)pyridine). Both cationic and neutral alkoxycarbene complexes undergo group transfer imination with azides, with the cationic derivative serving as a more efficient catalyst for cyclopentyl ether imination. Mechanistic studies support an iridium(I)dinitrogen complex as the resting state in the dark and a role for light-promoted N2 dissociation. Isoamyl nitrite and phenyl ethyl ketene are also found to engage with the cationic alkoxycarbene complex in formal alkoxide and O atom transfer reactions, respectively. In the former case an isolable dialkoxyalkyliridium complex is obtained, representing only the second example of a structurally characterized dialkoxyalkyl complex of a transition metal.
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Affiliation(s)
- Scott M Chapp
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 27235 United States
| | - Nathan D Schley
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 27235 United States
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Leforestier B, Gyton MR, Chaplin AB. Synthesis and group 9 complexes of macrocyclic PCP and POCOP pincer ligands. Dalton Trans 2020; 49:2087-2101. [PMID: 32031194 DOI: 10.1039/c9dt04835a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The synthesis of macrocyclic variants of commonly employed phosphine-based pincer (pro)ligands derived from meta-xylene (PCP-14) and resorcinol (POCOP-14) is described, where the P-donors are trans-substituted with a tetradecamethylene linker. The former was accomplished using a seven-step asymmetric procedure involving (-)-cis-1-amino-2-indanol as a chiral auxiliary and ring-closing olefin metathesis. A related, but non-diastereoselective route was employed for the latter, which consequently necessitated chromatographic separation from the cis-substituted by-product. The proligands are readily metalated and homologous series of MI(CO) and MIIICl2(CO) derivatives (M = Rh, Ir) have been isolated and fully characterised in solution and the solid state. Metal hydride complexes are generated during the synthesis of the former and have been characterised in situ using NMR spectroscopy.
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Affiliation(s)
- Baptiste Leforestier
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
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Hood TM, Gyton MR, Chaplin AB. Synthesis and rhodium complexes of macrocyclic PNP and PONOP pincer ligands. Dalton Trans 2020; 49:2077-2086. [PMID: 31912067 DOI: 10.1039/c9dt04474d] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of macrocyclic variants of commonly employed phosphine-based pincer ligands derived from lutidine (PNP-14) and 2,6-dihydroxypyridine (PONOP-14) is described, where the P-donors are trans-substituted with a tetradecamethylene linker. This was accomplished using an eight-step procedure involving borane protection, ring-closing olefin metathesis, chromatographic separation from the cis-substituted diastereomers, and borane deprotection. The rhodium coordination chemistry of these ligands has been explored, aided by the facile synthesis of 2,2'-biphenyl (biph) adducts [Rh(PNP-14)(biph)][BArF4] and [Rh(PONOP-14)(biph)][BArF4] (ArF = 3,5-(CF3)2C6H3). Subsequent hydrogenolysis enabled generation of dihydrogen, ethylene and carbonyl derivatives; notably the ν(CO) bands of the carbonyl complexes provide a means to compare the donor properties of the new pincer ligands with established acyclic congeners.
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Affiliation(s)
- Thomas M Hood
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
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Hood TM, Chaplin AB. Reactions of Rh(PNP) pincer complexes with terminal alkynes: homocoupling through a ring or not at all. Dalton Trans 2020; 49:16649-16652. [DOI: 10.1039/d0dt03550e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
“Switching on” a metal's capacity to promote terminal alkyne coupling reactions using a macrocyclic pincer ligand.
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Affiliation(s)
- Thomas M. Hood
- Department of Chemistry
- University of Warwick
- Coventry CV4 7AL
- UK
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