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Turnbull D, Légaré MA. Rapid, iterative syntheses of unsymmetrical di- and triarylboranes from crystalline aryldifluoroboranes. Chem Sci 2023; 14:14256-14261. [PMID: 38098724 PMCID: PMC10717494 DOI: 10.1039/d3sc05071h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 11/16/2023] [Indexed: 12/17/2023] Open
Abstract
A one-pot procedure to synthesise aryldifluoroboranes, ArBF2, from bench-stable arylsilanes is presented. These ArBF2 react conveniently with aryllithium reagents to form unsymmetrical ArAr'BF and BArAr'Ar'' in high yield. Examples of all three classes of borane have been characterised crystallographically, allowing for elucidation of geometric and crystal packing trends in crystalline ArBF2.
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Affiliation(s)
- Douglas Turnbull
- Department of Chemistry, McGill University Otto Maass Chemistry Building, 801 Rue Sherbrooke O Montreal Quebec Canada H3A 0B8
| | - Marc-André Légaré
- Department of Chemistry, McGill University Otto Maass Chemistry Building, 801 Rue Sherbrooke O Montreal Quebec Canada H3A 0B8
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2
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Akram MO, Tidwell JR, Dutton JL, Martin CD. Tris(ortho-carboranyl)borane: An Isolable, Halogen-Free, Lewis Superacid. Angew Chem Int Ed Engl 2022; 61:e202212073. [PMID: 36135949 PMCID: PMC9828388 DOI: 10.1002/anie.202212073] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Indexed: 01/12/2023]
Abstract
The synthesis of tris(ortho-carboranyl)borane (BoCb3 ), a single site neutral Lewis superacid, in one pot from commercially available materials is achieved. The high fluoride ion affinity (FIA) confirms its classification as a Lewis superacid and the Gutmann-Beckett method as well as adducts with Lewis bases indicate stronger Lewis acidity over the widely used fluorinated aryl boranes. The electron withdrawing effect of ortho-carborane and lack of pi-delocalization of the LUMO rationalize the unusually high Lewis acidity. Catalytic studies indicate that BoCb3 is a superior catalyst for promoting C-F bond functionalization reactions than tris(pentafluorophenyl)borane [B(C6 F5 )3 ].
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Affiliation(s)
- Manjur O. Akram
- Department of Chemistry and BiochemistryBaylor UniversityOne Bear Place #97348WacoTX 76798USA
| | - John R. Tidwell
- Department of Chemistry and BiochemistryBaylor UniversityOne Bear Place #97348WacoTX 76798USA
| | - Jason L. Dutton
- Department of Biochemistry and ChemistryLa Trobe Institute for Molecular ScienceLa Trobe UniversityMelbourneVictoria3086Australia
| | - Caleb D. Martin
- Department of Chemistry and BiochemistryBaylor UniversityOne Bear Place #97348WacoTX 76798USA
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3
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Norwine EE, Kiernicki JJ, Zeller M, Szymczak NK. Distinct Reactivity Modes of a Copper Hydride Enabled by an Intramolecular Lewis Acid. J Am Chem Soc 2022; 144:15038-15046. [PMID: 35960993 PMCID: PMC10291504 DOI: 10.1021/jacs.2c02937] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We disclose a 1,4,7-triazacyclononane (TACN) ligand featuring an appended boron Lewis acid. Metalation with Cu(I) affords a series of tetrahedral complexes including a boron-capped cuprous hydride. We demonstrate distinct reactivity modes as a function of chemical oxidation: hydride transfer to CO2 in the copper(I) state and oxidant-induced H2 evolution as well as alkyne reduction.
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Affiliation(s)
- Emily E. Norwine
- University of Michigan, 930 N. University, Ann Arbor, MI 48109 (USA)
| | - John J. Kiernicki
- University of Michigan, 930 N. University, Ann Arbor, MI 48109 (USA)
| | - Matthias Zeller
- H. C. Brown Laboratory, Purdue University, 560 Oval Dr., West Lafayette, IN 47907 (USA)
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4
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Abstract
In the last two decades, boron-based catalysis has been gaining increasing traction in the field of organic synthesis. The use of halogenated triarylboranes as main group Lewis acid catalysts is an attractive strategy. It has been applied in a growing number of transformations over the years, where they may perform comparably or even better than the gold standard catalysts. This review discusses methods of borane synthesis and cutting-edge boron-based Lewis acid catalysis, focusing especially on tris(pentafluorophenyl)-borane [B(C6F5)3], and other halogenated triarylboranes, highlighting how boron Lewis acids employed as catalysts can unlock a plethora of unprecedented chemical transformations or improve the efficiency of existing reactions.
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5
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Ferger M, Berger SM, Rauch F, Schönitz M, Rühe J, Krebs J, Friedrich A, Marder TB. Synthesis of Highly Functionalizable Symmetrically and Unsymmetrically Substituted Triarylboranes from Bench-Stable Boron Precursors. Chemistry 2021; 27:9094-9101. [PMID: 33844337 PMCID: PMC8360097 DOI: 10.1002/chem.202100632] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Indexed: 02/04/2023]
Abstract
A novel and convenient methodology for the one-pot synthesis of sterically congested triarylboranes by using bench-stable aryltrifluoroborates as the boron source is reported. This procedure gives systematic access to symmetrically and unsymmetrically substituted triarylboranes of the types BAr2 Ar' and BArAr'Ar'', respectively. Three unsymmetrically substituted triarylboranes as well as their iridium-catalyzed C-H borylation products are reported. These borylated triarylboranes contain one to three positions that can subsequently be orthogonally functionalized in follow-up reactions, such as Suzuki-Miyaura cross-couplings or Sonogashira couplings.
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Affiliation(s)
- Matthias Ferger
- Institut für Anorganische Chemie andInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Sarina M. Berger
- Institut für Anorganische Chemie andInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Florian Rauch
- Institut für Anorganische Chemie andInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Markus Schönitz
- Institut für Anorganische Chemie andInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Jessica Rühe
- Institut für Anorganische Chemie andInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Johannes Krebs
- Institut für Anorganische Chemie andInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Alexandra Friedrich
- Institut für Anorganische Chemie andInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Todd B. Marder
- Institut für Anorganische Chemie andInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
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6
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Berger SM, Ferger M, Marder TB. Synthetic Approaches to Triarylboranes from 1885 to 2020. Chemistry 2021; 27:7043-7058. [PMID: 33443314 PMCID: PMC8247992 DOI: 10.1002/chem.202005302] [Citation(s) in RCA: 27] [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: 12/11/2020] [Indexed: 12/21/2022]
Abstract
In recent years, research in the fields of optoelectronics, anion sensors and bioimaging agents have been greatly influenced by novel compounds containing triarylborane motifs. Such compounds possess an empty p-orbital at boron which results in useful optical and electronic properties. Such a diversity of applications was not expected when the first triarylborane was reported in 1885. Synthetic approaches to triarylboranes underwent various changes over the following century, some of which are still used in the present day, such as the generally applicable routes developed by Krause et al. in 1922, or by Grisdale et al. in 1972 at Eastman Kodak. Some other developments were not pursued further after their initial reports, such as the synthesis of two triarylboranes bearing three different aromatic groups by Mikhailov et al. in 1958. This review summarizes the development of synthetic approaches to triarylboranes from their first report nearly 135 years ago to the present.
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Affiliation(s)
- Sarina M. Berger
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry, & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Matthias Ferger
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry, & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Todd B. Marder
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry, & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
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7
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Yang DT, Zheng J, Peng JB, Wang X, Wang S. Sequential and Diverse Synthesis of BN-Heterocycles and Investigation of Their Photoreactivity. J Org Chem 2020; 86:829-836. [PMID: 33315397 DOI: 10.1021/acs.joc.0c02379] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Substituents modification of BN-heterocycles on the boron atom has proven important to the photoreactivity and optoelectronic properties of BN-heterocycles. We developed a sequential and diverse synthetic strategy toward BN-heterocycles, in which the boron building block can be introduced with fully pre-functionalized substituents (Route A) or the substituents can be partially (Route B) or fully (Route C) modified after borylation. These three routes are complementary to provide more diverse BN-heterocycles, which will find broad applications in manipulating/controlling molecular transformations and the development of new photoresponsive materials.
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Affiliation(s)
- Deng-Tao Yang
- Institute of Advanced Synthesis, Northwestern Polytechnical University, Xi'an, 710072, China.,Yangtze River Delta Research Institute, Northwestern Polytechnical University, Taicang, Jiangsu 215400, China.,Department of Chemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Jie Zheng
- Department of Chemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Jin-Bao Peng
- Department of Chemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Xiang Wang
- Department of Chemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Suning Wang
- Department of Chemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada
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Carden JL, Dasgupta A, Melen RL. Halogenated triarylboranes: synthesis, properties and applications in catalysis. Chem Soc Rev 2020; 49:1706-1725. [PMID: 32100762 DOI: 10.1039/c9cs00769e] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Halogenated triarylboranes (BAr3) have been known for decades, however it has only been since the surge of interest in main group catalysis that their application as strong Lewis acid catalysts has been recognised. This review aims to look past the popular tris(pentafluorophenyl)borane [B(C6F5)3] to the other halogenated triarylboranes, to give a greater breadth of understanding as to how tuning the Lewis acidity of BAr3 by modifications of the aryl rings can lead to improved reactivity. In this review, a discussion on Lewis acidity determination of boranes is given, the synthesis of these boranes is discussed, and examples of how they are being used for catalysis and frustrated Lewis pair (FLP) chemistry are explained.
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Affiliation(s)
- Jamie L Carden
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, Cymru/Wales, UK.
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Bennett EL, Lawrence EJ, Blagg RJ, Mullen AS, MacMillan F, Ehlers AW, Scott DJ, Sapsford JS, Ashley AE, Wildgoose GG, Slootweg JC. A New Mode of Chemical Reactivity for Metal-Free Hydrogen Activation by Lewis Acidic Boranes. Angew Chem Int Ed Engl 2019; 58:8362-8366. [PMID: 30968535 PMCID: PMC6594078 DOI: 10.1002/anie.201900861] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/09/2019] [Indexed: 12/13/2022]
Abstract
We herein explore whether tris(aryl)borane Lewis acids are capable of cleaving H2 outside of the usual Lewis acid/base chemistry described by the concept of frustrated Lewis pairs (FLPs). Instead of a Lewis base we use a chemical reductant to generate stable radical anions of two highly hindered boranes: tris(3,5-dinitromesityl)borane and tris(mesityl)borane. NMR spectroscopic characterization reveals that the corresponding borane radical anions activate (cleave) dihydrogen, whilst EPR spectroscopic characterization, supported by computational analysis, reveals the intermediates along the hydrogen activation pathway. This radical-based, redox pathway involves the homolytic cleavage of H2 , in contrast to conventional models of FLP chemistry, which invoke a heterolytic cleavage pathway. This represents a new mode of chemical reactivity for hydrogen activation by borane Lewis acids.
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Affiliation(s)
- Elliot L. Bennett
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Elliot J. Lawrence
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Robin J. Blagg
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Anna S. Mullen
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Fraser MacMillan
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Andreas W. Ehlers
- Van 't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 904, PO Box 941571090 GDAmsterdamThe Netherlands
- Department of Chemistry, Science FacultyUniversity of JohannesburgPO Box 254, Auckland ParkJohannesburgSouth Africa
| | - Daniel J. Scott
- Molecular Sciences Research HubImperial College White City Campus80 Wood LaneLondonW12 0BZUK
| | - Joshua S. Sapsford
- Molecular Sciences Research HubImperial College White City Campus80 Wood LaneLondonW12 0BZUK
| | - Andrew E. Ashley
- Molecular Sciences Research HubImperial College White City Campus80 Wood LaneLondonW12 0BZUK
| | - Gregory G. Wildgoose
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - J. Chris Slootweg
- Van 't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 904, PO Box 941571090 GDAmsterdamThe Netherlands
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10
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Bennett EL, Lawrence EJ, Blagg RJ, Mullen AS, MacMillan F, Ehlers AW, Scott DJ, Sapsford JS, Ashley AE, Wildgoose GG, Slootweg JC. A New Mode of Chemical Reactivity for Metal‐Free Hydrogen Activation by Lewis Acidic Boranes. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201900861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Elliot L. Bennett
- School of ChemistryUniversity of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Elliot J. Lawrence
- School of ChemistryUniversity of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Robin J. Blagg
- School of ChemistryUniversity of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Anna S. Mullen
- School of ChemistryUniversity of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Fraser MacMillan
- School of ChemistryUniversity of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Andreas W. Ehlers
- Van 't Hoff Institute for Molecular SciencesUniversity of Amsterdam Science Park 904, PO Box 94157 1090 GD Amsterdam The Netherlands
- Department of Chemistry, Science FacultyUniversity of Johannesburg PO Box 254, Auckland Park Johannesburg South Africa
| | - Daniel J. Scott
- Molecular Sciences Research HubImperial College White City Campus 80 Wood Lane London W12 0BZ UK
| | - Joshua S. Sapsford
- Molecular Sciences Research HubImperial College White City Campus 80 Wood Lane London W12 0BZ UK
| | - Andrew E. Ashley
- Molecular Sciences Research HubImperial College White City Campus 80 Wood Lane London W12 0BZ UK
| | - Gregory G. Wildgoose
- School of ChemistryUniversity of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - J. Chris Slootweg
- Van 't Hoff Institute for Molecular SciencesUniversity of Amsterdam Science Park 904, PO Box 94157 1090 GD Amsterdam The Netherlands
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Xing JY, Buffet JC, Rees NH, Nørby P, O'Hare D. Hydrogen cleavage by solid-phase frustrated Lewis pairs. Chem Commun (Camb) 2018; 52:10478-81. [PMID: 27463124 DOI: 10.1039/c6cc04937k] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the direct synthesis of a solid-phase frustrated Lewis pair (s-FLP) by combining a silica-supported Lewis acid ([triple bond, length as m-dash]SiOB(C6F5)2, s-BCF) with a Lewis base (tri-tert-butylphosphine, (t)Bu3P) to give [[triple bond, length as m-dash]SiOB(C6F5)2][(t)Bu3P]. Reaction of this s-FLP with H2 under mild conditions led to heterolytic H-H bond cleavage and the formation of [[triple bond, length as m-dash]SiOB(H)(C6F5)2][(t)Bu3PH].
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Affiliation(s)
- Jun-Yi Xing
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Jean-Charles Buffet
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Nicholas H Rees
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Peter Nørby
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Dermot O'Hare
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
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