1
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Fan J, Koh AP, Zhou J, Zhang ZF, Wu CS, Webster RD, Su MD, So CW. Tetrakis( N-heterocyclic Carbene)-Diboron(0): Double Single-Electron-Transfer Reactivity. J Am Chem Soc 2023; 145:11669-11677. [PMID: 37201187 DOI: 10.1021/jacs.3c01801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The use of 1,3,4,5-tetramethylimidazol-2-ylidene (IMe) to coordinate with diatomic B2 species afforded a tetrakis(N-heterocyclic carbene)-diboron(0) [(IMe)2B-B(IMe)2] (2). The singly bonded B2 moiety therein possesses a valence electronic configuration 1σg21πu21πg*2 with four vacant molecular orbitals (1σu*, 2σg, 1πu', 1πg'*) coordinated with IMe. Its unprecedented electronic structure is analogous to the energetically unfavorable planar hydrazine with a D2h symmetry. The two highly reactive πg* antibonding electrons enable double single-electron-transfer (SET) reactivity in small-molecule activation. Compound 2 underwent a double SET reduction with CO2 to form two carbon dioxide radical anions CO2•-, which then reduced pyridine to yield a carboxylated pyridine reductive coupling dianion [O2CNC5(H)5-C5(H)5NCO2]2- and converted compound 2 to the tetrakis(N-heterocyclic carbene)-diborene dication [(IMe)2B═B(IMe)2]2+ (32+). This is a remarkable transition-metal-free SET reduction of CO2 without ultraviolet/visible (UV/vis) light conditions.
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Affiliation(s)
- Jun Fan
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 637371 Singapore
| | - An-Ping Koh
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 637371 Singapore
| | - Jingsong Zhou
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 637371 Singapore
| | - Zheng-Feng Zhang
- Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan
| | - Chi-Shiun Wu
- Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan
| | - Richard D Webster
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 637371 Singapore
| | - Ming-Der Su
- Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Cheuk-Wai So
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 637371 Singapore
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2
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Fan J, Yang MC, Su MD, So CW. N-Phosphinoamidinato Silylene- and Phosphine-Borylborylene Complexes. Inorg Chem 2023; 62:863-870. [PMID: 36600552 DOI: 10.1021/acs.inorgchem.2c03660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
This work describes a straightforward method to synthesize a borylborylene without proceeding via the rearrangement of a diborene. An amidinato amidosilylene [LSiNMe2] (L = PhC(NtBu)2) and PMe3 were reacted with an N-phosphinoamidinato diborane 1 and KC8 to form a stable silylene-borylborylene 2 and a persistent phosphine-borylborylene 3, respectively. Compound 2 is stable as the borylene center is well stabilized by the silylene donor and boryl substituent, whereas compound 3 is unstable in solution due to labile PMe3. The latter was illustrated by reacting compound 3 with Ar'NC (Ar' = 2,6-Me2C6H3), where Ar'NC displaced PMe3 and inserted into the N-phosphinoamidinate ligand and B-B bond to form compound 4.
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Affiliation(s)
- Jun Fan
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 637371 Singapore
| | - Ming-Chung Yang
- Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan
| | - Ming-Der Su
- Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan.,Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Cheuk-Wai So
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 637371 Singapore
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3
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Yadav R, Sinhababu S, Yadav R, Kundu S. Base-stabilized formally zero-valent mono and diatomic molecular main-group compounds. Dalton Trans 2022; 51:2170-2202. [PMID: 35040452 DOI: 10.1039/d1dt03569j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Various compounds are known for transition metals in their formal zero-oxidation state, while similar compounds of main-group elements are recently realized and limited to only a few examples. Lewis-base-stabilized mono and diatomic molecular species (B2, C, C2, Si, Si2, Ge, Ge2, Sn, P2, As2, Sb2) represent groundbreaking examples of main-group compounds with formally zero-oxidation state. In recent years, the isolation of low-valent main-group compounds has attracted increasing attention of both experimental and theoretical chemists. This is not only due to their fascinating electronic structures and exceptional reactivities, but also their use as valuable precursors for the synthesis of exotic yet important chemical species. This has led to a better understanding of the intricate balance of the donor-acceptor properties of the ligand(s) used to stabilize elements in a formally zero-oxidation state. Owing to the unusual oxidation state of the central element, many compounds containing formally zero-valent elements can efficiently activate otherwise inert small molecules. This review describes the synthesis, characterization, and reactivity of reported mono and diatomic formal zero-oxidation state main-group compounds. This review also emphasizes the comparative description of systems where different ligands are used to stabilize an element in its formal zero-oxidation state.
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Affiliation(s)
- Ravi Yadav
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110 016, India. .,Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany
| | - Soumen Sinhababu
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor St., Chicago, Illinois 60607, USA.
| | - Ritu Yadav
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110 016, India.
| | - Subrata Kundu
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110 016, India.
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4
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Lu W, Jayaraman A, Fantuzzi F, Dewhurst RD, Härterich M, Dietz M, Hagspiel S, Krummenacher I, Hammond K, Cui J, Braunschweig H. Ein unsymmetrisches, cyclisches Diboren basierend auf einem chelatisierenden CAAC‐Liganden sowie dessen Aktivierung kleiner Moleküle und Umlagerungsreaktionen. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202113947] [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)
- Wei Lu
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Key Laboratory of Green Chemistry & Technology of Ministry of Education College of Chemistry Sichuan University 29 Wangjiang Road Chengdu 610064 P. R. China
| | - Arumugam Jayaraman
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Felipe Fantuzzi
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- School of Physical Sciences Ingram Building University of Kent Park Wood Road Canterbury CT2 7NH United Kingdom
| | - Rian D. Dewhurst
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Marcel Härterich
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Maximilian Dietz
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Stephan Hagspiel
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Ivo Krummenacher
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Kai Hammond
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Jingjing Cui
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Holger Braunschweig
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
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5
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Lu W, Jayaraman A, Fantuzzi F, Dewhurst RD, Härterich M, Dietz M, Hagspiel S, Krummenacher I, Hammond K, Cui J, Braunschweig H. An Unsymmetrical, Cyclic Diborene Based on a Chelating CAAC Ligand and its Small-Molecule Activation and Rearrangement Chemistry. Angew Chem Int Ed Engl 2021; 61:e202113947. [PMID: 34750945 PMCID: PMC9299934 DOI: 10.1002/anie.202113947] [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: 10/14/2021] [Indexed: 01/15/2023]
Abstract
A one‐pot synthesis of a CAAC‐stabilized, unsymmetrical, cyclic diborene was achieved via consecutive two‐electron reduction steps from an adduct of CAAC and B2Br4(SMe2)2. Theoretical studies revealed that this diborene has a considerably smaller HOMO–LUMO gap than those of reported NHC‐ and phosphine‐supported diborenes. Complexation of the diborene with [AuCl(PCy3)] afforded two diborene–AuI π complexes, while reaction with DurBH2, P4 and a terminal acetylene led to the cleavage of B−H, P−P, and C−C π bonds, respectively. Thermal rearrangement of the diborene gave an electron‐rich cyclic alkylideneborane, which readily coordinated to AgI via its B=C double bond.
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Affiliation(s)
- Wei Lu
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, P. R. China
| | - Arumugam Jayaraman
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Felipe Fantuzzi
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,School of Physical Sciences, Ingram Building, University of Kent, Park Wood Road, Canterbury, CT2 7NH, United Kingdom
| | - Rian D Dewhurst
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Marcel Härterich
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Maximilian Dietz
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Stephan Hagspiel
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ivo Krummenacher
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Kai Hammond
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Jingjing Cui
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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6
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Bartholome TA, Martinez JJ, Kaur A, Wilson DJD, Dutton JL, Martin CD. Borataalkene Hydrofunctionalization Reactions. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00261] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tyler A. Bartholome
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Jesse J. Martinez
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Aishvaryadeep Kaur
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - David J. D. Wilson
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Jason L. Dutton
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Caleb D. Martin
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
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7
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Brückner T, Fantuzzi F, Stennett TE, Krummenacher I, Dewhurst RD, Engels B, Braunschweig H. Isolierung neutraler, mono‐ und dikationischer B
2
P
2
‐Ringe durch Addition eines Diphosphans an eine Bor‐Bor‐Dreifachbindung. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102218] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Tobias Brückner
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
| | - Felipe Fantuzzi
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
- Institut für Physikalische und Theoretische Chemie Julius-Maximilians-Universität Würzburg Emil-Fischer-Straße 42 97074 Würzburg Deutschland
| | - Tom E. Stennett
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
| | - Ivo Krummenacher
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
| | - Rian D. Dewhurst
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
| | - Bernd Engels
- Institut für Physikalische und Theoretische Chemie Julius-Maximilians-Universität Würzburg Emil-Fischer-Straße 42 97074 Würzburg Deutschland
| | - Holger Braunschweig
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
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8
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Brückner T, Fantuzzi F, Stennett TE, Krummenacher I, Dewhurst RD, Engels B, Braunschweig H. Isolation of Neutral, Mono-, and Dicationic B 2 P 2 Rings by Diphosphorus Addition to a Boron-Boron Triple Bond. Angew Chem Int Ed Engl 2021; 60:13661-13665. [PMID: 33844394 PMCID: PMC8252364 DOI: 10.1002/anie.202102218] [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: 02/12/2021] [Revised: 04/09/2021] [Indexed: 01/10/2023]
Abstract
The NHC-stabilised diboryne (B2 (SIDep)2 ; SIDep=1,3-bis(2,6-diethylphenyl)imidazolin-2-ylidene) undergoes a high-yielding P-P bond activation with tetraethyldiphosphine at room temperature to form a B2 P2 heterocycle via a diphosphoryldiborene by 1,2-diphosphination. The heterocycle can be oxidised to a radical cation and a dication, respectively, depending on the oxidant used and its counterion. Starting from the planar, neutral 1,3-bis(alkylidene)-1,3-diborata-2,4-diphosphoniocyclobutane, each oxidation step leads to decreased B-B distances and loss of planarity by cationisation. X-ray analyses in conjunction with DFT and CASSCF/NEVPT2 calculations reveal closed-shell singlet, butterfly-shaped structures for the NHC-stabilised dicationic B2 P2 rings, with their diradicaloid, planar-ring isomers lying close in energy.
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Affiliation(s)
- Tobias Brückner
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97070, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97070, Würzburg, Germany
| | - Felipe Fantuzzi
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97070, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97070, Würzburg, Germany.,Institute for Physical and Theoretical Chemistry, Julius-Maximilians-Universität Würzburg, Emil-Fischer-Strasse 42, 97074, Würzburg, Germany
| | - Tom E Stennett
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97070, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97070, Würzburg, Germany
| | - Ivo Krummenacher
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97070, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97070, Würzburg, Germany
| | - Rian D Dewhurst
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97070, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97070, Würzburg, Germany
| | - Bernd Engels
- Institute for Physical and Theoretical Chemistry, Julius-Maximilians-Universität Würzburg, Emil-Fischer-Strasse 42, 97074, Würzburg, Germany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97070, Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97070, Würzburg, Germany
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9
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Fan J, Mah JQ, Yang MC, Su MD, So CW. A N-Phosphinoamidinato NHC-Diborene Catalyst for Hydroboration. J Am Chem Soc 2021; 143:4993-5002. [PMID: 33448848 DOI: 10.1021/jacs.0c12627] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The use of the N-phosphinoamidinato NHC-diborene catalyst 2 for hydroboration is described. The N-phosphinoamidine tBu2PN(H)C(Ph)═N(2,6-iPr2C6H3) was reacted with nBuLi in Et2O to afford the lithium derivative, which was then treated with B2Br4(SMe2)2 in toluene to form the N-phosphinoamidinate-bridged diborane 1. It was reacted with the N-heterocyclic carbene IMe (:C{N(CH3)C(CH3)}2) and excess potassium graphite at room temperature in toluene to give the N-phosphinoamidinato NHC-diborene compound 2. It can stoichiometrically activate ammonia-borane and carbon dioxide. It also showed catalytic capability. A 2 mol % portion of 2 catalyzed the hydroboration of carbon dioxide (CO2) with pinacolborane (HBpin) in deuterated benzene (C6D6) at 110 °C (conversion >99%), which afforded the methoxyborane [pinBOMe] (yield 97.8%, TOF 33.3 h-1) and the bis(boryl) oxide [(pinB)2O]. In addition, 5 mol % of 2 catalyzed the N-formylation of secondary and primary amines by carbon dioxide and pinacolborane to yield the N-formamides (average yield 91.6%, TOF 25.9 h-1). Moreover, 2 showed chemoselectivity toward catalytic hydroboration of carbonyl compounds. In mechanistic studies, the B═B double bond in compound 2 activated the substrates, the intermediates of which then underwent hydroboration with pinacolborane to yield the products and regenerate catalyst 2.
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Affiliation(s)
- Jun Fan
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Jian-Qiang Mah
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Ming-Chung Yang
- Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan
| | - Ming-Der Su
- Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan.,Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Cheuk-Wai So
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
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10
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Brückner T, Heß M, Stennett TE, Rempel A, Braunschweig H. Synthesis of Boron Analogues of Enamines via Hydroamination of a Boron-Boron Triple Bond. Angew Chem Int Ed Engl 2021; 60:736-741. [PMID: 33058434 PMCID: PMC7839459 DOI: 10.1002/anie.202012101] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/14/2020] [Indexed: 01/24/2023]
Abstract
An N-heterocyclic-carbene-stabilized diboryne undergoes rapid, high-yielding and catalyst-free hydroamination reactions with primary amines, yielding 1-amino-2-hydrodiborenes, which can be considered boron analogues of enamines. The electronics of the organic substituent at nitrogen influence the structure and further reactivity of the diborene product. With electron-rich anilines, a second hydroamination can occur at the diborene to generate 1,1-diamino-2,2-dihydrodiboranes. With isopropylamine, the electronic influence of the alkyl substituent upon the diborene leads to an unprecedented boron-mediated intramolecular N-dearylation reaction of an N-heterocyclic carbene unit.
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Affiliation(s)
- Tobias Brückner
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97070WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97070WürzburgGermany
| | - Merlin Heß
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97070WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97070WürzburgGermany
| | - Tom E. Stennett
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97070WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97070WürzburgGermany
| | - Anna Rempel
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97070WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97070WürzburgGermany
| | - Holger Braunschweig
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97070WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97070WürzburgGermany
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Brückner T, Heß M, Stennett TE, Rempel A, Braunschweig H. Herstellung von Boranaloga von Enaminen über Hydroaminierung einer Bor‐Bor‐Dreifachbindung. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202012101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Tobias Brückner
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
| | - Merlin Heß
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
| | - Tom E. Stennett
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
| | - Anna Rempel
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
| | - Holger Braunschweig
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97070 Würzburg Deutschland
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