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Gauthier R, Paquin JF. Hydrofluorination of Alkynes: From (E) to (Z). Chemistry 2023; 29:e202301896. [PMID: 37458694 DOI: 10.1002/chem.202301896] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Indexed: 09/09/2023]
Abstract
The hydrofluorination of alkynes is an efficient synthetic route to monofluoroalkenes or difluoroalkanes. Both fluorinated motifs have found applications in medicinal chemistry and beyond. This review explores the recent advances in the hydrofluorination of diverse alkynes through various activation methods, from classical coinage metal catalysis to metal-free conditions. The range of alkynes goes from the simplest unactivated alkynes to activated ones (ynones and derivatives, ynamides, alkynyl sulfides and sulfones as much as haloalkynes). Regio- and stereoselective methods exists, but there is still room for improvement depending on the type of alkyne.
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Affiliation(s)
- Raphaël Gauthier
- PROTEO, CCVC, Département de chimie, Université Laval, 1045 avenue de la Médecine, Québec, QC, G1V 0A6, Canada
| | - Jean-François Paquin
- PROTEO, CCVC, Département de chimie, Université Laval, 1045 avenue de la Médecine, Québec, QC, G1V 0A6, Canada
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2
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Sander S, Cosgrove EJ, Müller R, Kaupp M, Braun T. Hydrogen Bonding in Platinum Indolylphosphine Polyfluorido and Fluorido Complexes. Chemistry 2023; 29:e202202768. [PMID: 36327144 PMCID: PMC10107128 DOI: 10.1002/chem.202202768] [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: 09/05/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 11/06/2022]
Abstract
The reaction of the Pt complexes cis-[Pt(CH3 )(Ar){Ph2 P(Ind)}2 ] (Ind=2-(3-methyl)indolyl, Ar=4-tBuC6 H4 (1 a), 4-CH3 C6 H4 (1 b), Ph (1 c), 4-FC6 H4 (1 d), 4-ClC6 H4 (1 e), 4-CF3 C6 H4 (1 f)) with HF afforded the polyfluorido complexes trans-[Pt(F(HF)2 )(Ar){Ph2 P(Ind)}2 ] 2 a-f, which can be converted into the fluoride derivatives trans-[Pt(F)(Ar){Ph2 P(Ind)}2 ] (3 a-f) by treatment with CsF. The compounds 2 a-f and 3 a-f were characterised thoroughly by multinuclear NMR spectroscopy. The data reveal hydrogen bonding of the fluorido ligand with HF molecules and the indolylphosphine ligand. Polyfluorido complexes 2 a-f show larger |1 J(F,Pt)|, but lower 1 J(H,F) coupling constants when compared to the fluorido complexes 3 a-f. Decreasing 1 J(P,Pt) coupling constants in 2 a-f and 3 a-f suggest a cis influence of the aryl ligands in the following order: 4-tBuC6 H4 (a) ≈4-CH3 C6 H4 (b)<Ph (c)≪4-FC6 H4 (d)<4-ClC6 H4 (e)<4-CF3 C6 H4 (f). In addition, the larger cis influence of aryl ligands bearing electron-withdrawing groups in the para position correlates with decreasing magnitudes of |1 J(F,Pt)| coupling constants. The interpretation of the experimental data was supported by quantum-chemical DFT calculations.
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Affiliation(s)
- Stefan Sander
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany
| | - Elizabeth J Cosgrove
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany
| | - Robert Müller
- Institut für Chemie, Technische Universität Berlin, Theoretische Chemie/Quantenchemie, Sekr.C7, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Martin Kaupp
- Institut für Chemie, Technische Universität Berlin, Theoretische Chemie/Quantenchemie, Sekr.C7, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Thomas Braun
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany
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Jos S, Tan C, Thilmany P, Saadane A, Slebodnick C, Evano G, Santos WL. Phosphine-catalyzed regio- and stereo-selective hydroboration of ynamides to ( Z)-β-borylenamides. Chem Commun (Camb) 2022; 58:13751-13754. [PMID: 36416159 DOI: 10.1039/d2cc04543e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We report a tri-n-butyl phosphine catalyzed regio- and stereo-selective hydroboration of ynamides to yield (Z)-β-borylenamides in good yields. Surprisingly, a formal cis addition to the triple bond was observed as confirmed by NMR and X-ray crystallography. 31P NMR studies suggest that a zwitterionic vinylphosphonium intermediate is key in the mechanism. The resulting products were further transformed to β-CF3 enamides via stereoretentive trifluoromethylation.
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Affiliation(s)
- Swetha Jos
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia, USA.
| | - Christine Tan
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia, USA.
| | - Pierre Thilmany
- Laboratoire de Chimie Organique, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles, Avenue F. D. Roosevelt 50, CP160/06, 1050 Brussels, Belgium
| | - Alaâ Saadane
- Laboratoire de Chimie Organique, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles, Avenue F. D. Roosevelt 50, CP160/06, 1050 Brussels, Belgium
| | - Carla Slebodnick
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia, USA.
| | - Gwilherm Evano
- Laboratoire de Chimie Organique, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles, Avenue F. D. Roosevelt 50, CP160/06, 1050 Brussels, Belgium
| | - Webster L Santos
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia, USA.
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Sander S, Braun T. Platinum‐Catalyzed Hydrofluorination of Alkynes: Hydrogen Bonding to Indolylphosphine Ligands to Provide Fluoride Reactivity. Angew Chem Int Ed Engl 2022; 61:e202204678. [PMID: 35420731 PMCID: PMC9401575 DOI: 10.1002/anie.202204678] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Indexed: 11/20/2022]
Abstract
The reaction of the Pt complexes cis‐[Pt(CH3)2{R2P(Ind)}2] (Ind=2‐(3‐methyl)indolyl, R=Ph (1 a), 4‐FC6H4 (1 b), 4‐CF3C6H4 (1 c)) with HF afforded the fluorido complexes trans‐[Pt(F(HF)2)(CH3){R2P(Ind)}2] 2 a–c, which can be converted into trans‐[Pt(F)(CH3){R2P(Ind)}2] (3 a–c) by treatment with CsF. Addition of 3‐hexyne to 2 a–c gave alkyne complexes trans‐[Pt(C,C‐η2‐C2H5C≡CC2H5)(CH3){R2P(Ind)}2{F(HF)2}] (4 a–c) at which a fluoride is stabilised as polyfluoride in the coordination sphere by hydrogen bonding to the indolyl‐substituted phosphine ligands. Subsequent heating of a solution of 4 a in the presence of PVPHF led to fluoroalkene formation. Selective catalytic hydrofluorination of alkynes to yield (Z)‐fluoroalkenes were developed. The ability of hydrogen bonding to polyfluoride favours the fluorination step as demonstrated by studies with complexes bearing no indolyl groups at the phosphine ligands.
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Affiliation(s)
- Stefan Sander
- Department of Chemistry Humboldt Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Thomas Braun
- Department of Chemistry Humboldt Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
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Sander S, Braun T. Platinum‐Catalyzed Hydrofluorination of Alkynes: Hydrogen Bonding to Indolylphosphine Ligands to Provide Fluoride Reactivity. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202204678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Stefan Sander
- Humboldt-Universität zu Berlin: Humboldt-Universitat zu Berlin chemistry GERMANY
| | - Thomas Braun
- Humboldt University Chemistry Brook-Taylor Str. 2 12489 Berlin GERMANY
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Rachor SG, Müller R, Wittwer P, Kaupp M, Braun T. Synthesis, Reactivity, and Bonding of Gold(I) Fluorido-Phosphine Complexes. Inorg Chem 2021; 61:357-367. [PMID: 34913690 DOI: 10.1021/acs.inorgchem.1c02959] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Gold(I) fluorido complexes with phosphine ligands have been synthesized from their respective iodido precursors. The bonding situation in comparison between complexes bearing phosphines and N-heterocyclic carbenes (NHCs) was explored quantum-chemically, obtaining similar results for both. Calculations of the 19F NMR chemical shifts match the experimental values well, including the approximately 40 ppm low-field shifts for the phosphine complexes compared to the NHC complexes, in spite of similar negative charges on fluorine. The reactivity of the highly water-sensitive gold(I) fluorido complexes was studied, resulting in substitution at the metal using trimethylsilyl reagents. The compounds studied were characterized using NMR as well as X-ray diffraction methods.
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Affiliation(s)
- Simon G Rachor
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Robert Müller
- Institut für Chemie, Theoretische Chemie/Quantenchemie, Technische Universität Berlin, Sekr. C7, Strasse des 17 Juni 135, 10623 Berlin, Germany
| | - Philipp Wittwer
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Martin Kaupp
- Institut für Chemie, Theoretische Chemie/Quantenchemie, Technische Universität Berlin, Sekr. C7, Strasse des 17 Juni 135, 10623 Berlin, Germany
| | - Thomas Braun
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
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Sander S, Müller R, Ahrens M, Kaupp M, Braun T. Platinum Indolylphosphine Fluorido and Polyfluorido Complexes: An Interplay between Cyclometallation, Fluoride Migration, and Hydrogen Bonding. Chemistry 2021; 27:14287-14298. [PMID: 34337795 PMCID: PMC8596594 DOI: 10.1002/chem.202102451] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Indexed: 11/06/2022]
Abstract
The reaction of [PtCl2 (COD)] (COD=1,5-cyclooctadiene) with diisopropyl-2-(3-methyl)indolylphosphine (iPr2 P(C9 H8 N)) led to the formation of the platinum(ii) chlorido complexes, cis-[PtCl2 {iPr2 P(C9 H8 N)}2 ] (1) and trans-[PtCl2 {iPr2 P(C9 H8 N)}2 ] (2). The cis-complex 1 reacted with NEt3 yielding the complex cis-[PtCl{κ2 -(P,N)-iPr2 P(C9 H7 N)}{iPr2 P(C9 H8 N)}] (3) bearing a cyclometalated κ2 -(P,N)-phosphine ligand, while the isomer 2 with a trans-configuration did not show any reactivity towards NEt3 . Treatment of 1 or 3 with (CH3 )4 NF (TMAF) resulted in the formation of the twofold cyclometalated complex cis-[Pt{κ2 -(P,N)-iPr2 P(C9 H7 N)}2 ] (4). The molecular structures of the complexes 1-4 were determined by single-crystal X-ray diffraction. The fluorido complex cis-[PtF{κ2 -(P,N)-iPr2 P(C9 H7 N)}{iPr2 P(C9 H8 N)}] ⋅ (HF)4 (5 ⋅ (HF)4 ) was formed when complex 4 was treated with different hydrogen fluoride sources. The Pt(ii) fluorido complex 5 ⋅ (HF)4 exhibits intramolecular hydrogen bonding in its outer coordination sphere between the fluorido ligand and the NH group of the 3-methylindolyl moiety. In contrast to its chlorido analogue 3, complex 5 ⋅ (HF)4 reacted with CO or the ynamide 1-(2-phenylethynyl)-2-pyrrolidinone to yield the complexes trans-[Pt(CO){κ2 -(P,C)-iPr2 P(C9 H7 NCO)}{iPr2 P(C9 H8 N)}][F(HF)4 ] (7) and a complex, which we suggest to be cis-[Pt{C=C(Ph)OCN(C3 H6 )}{κ2 -(P,N)-iPr2 P(C9 H7 N)}{iPr2 P(C9 H8 N)}][F(HF)4 ] (9), respectively. The structure of 9 was assigned on the basis of DFT calculations as well as NMR and IR data. Hydrogen bonding of HF and NH to fluoride was proven to be crucial for the existence of 7 and 9.
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Affiliation(s)
- Stefan Sander
- Department of ChemistryHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
| | - Robert Müller
- Institut für ChemieTechnische Universität Berlin, Theoretische Chemie/Quantenchemie, Sekr.C7Straße des 17. Juni 13510623BerlinGermany
| | - Mike Ahrens
- Department of ChemistryHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
| | - Martin Kaupp
- Institut für ChemieTechnische Universität Berlin, Theoretische Chemie/Quantenchemie, Sekr.C7Straße des 17. Juni 13510623BerlinGermany
| | - Thomas Braun
- Department of ChemistryHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
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