1
|
Phatake RS, Averdunk A, Würtele C, Gellrich U. Piers’ Borane-Catalyzed Dimerization of Arylallenes via Transborylation: A Synthetic and Mechanistic Study. ACS Catal 2022. [DOI: 10.1021/acscatal.2c04605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ravindra S. Phatake
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
| | - Arthur Averdunk
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
| | - Christian Würtele
- Institut für Anorganische und Analytische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
| | - Urs Gellrich
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392Gießen, Germany
| |
Collapse
|
2
|
Averdunk A, Hasenbeck M, Müller T, Becker J, Gellrich U. 1,2-Carboboration of Arylallenes by In Situ Generated Alkenylboranes for the Synthesis of 1,4-Dienes. Chemistry 2022; 28:e202200470. [PMID: 35348257 PMCID: PMC9325554 DOI: 10.1002/chem.202200470] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Indexed: 12/26/2022]
Abstract
We herein report a novel method for the coupling of unactivated alkynes and arylallenes, which relies on an unprecedented and regioselective 1,2‐carboboration of the allene by an alkenylborane. The alkenylborane is conveniently prepared in situ by hydroboration of an alkyne with Piers’ borane, i. e., HB(C6F5)2. The boryl‐substituted 1,4‐dienes that are formed by this carboboration are well‐suited for a subsequent Suzuki‐Miyaura coupling with aryl iodides. This allowed us to develop a three‐step, one‐pot protocol for the synthesis of aryl‐substituted 1,4‐dienes. The generality of the reaction was demonstrated by the synthesis of twenty dienes with modular variations of all three reaction partners. The mechanism of the new 1,2‐carboboration was investigated using dispersion corrected double‐hybrid DFT computations that allowed us to rationalize the chemo‐ and regioselectivity of this key step.
Collapse
Affiliation(s)
- Arthur Averdunk
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Max Hasenbeck
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Tizian Müller
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Jonathan Becker
- Institut für Anorganische und Analytische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Urs Gellrich
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| |
Collapse
|
3
|
Hasenbeck M, Müller T, Averdunk A, Becker J, Gellrich U. Piers' Borane-Induced Tetramerization of Arylacetylenes. Chemistry 2021; 28:e202104254. [PMID: 34882876 PMCID: PMC9303334 DOI: 10.1002/chem.202104254] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Indexed: 12/22/2022]
Abstract
We herein report that the reaction of Piers′ borane, i. e. HB(C6F5)2, with an excess of arylacetylenes at room temperature leads to tetramerization of the acetylene and the diastereoselective formation of boryl‐substituted tetra‐aryl‐tetrahydropentalenes. The reaction mechanism was investigated by isotope labeling experiments and DFT computations. These investigations indicate that a series of 1,2‐carboboration reactions form an octatetraene that undergoes an electrocyclization. Two skeletal rearrangements then presumably lead to the formation of the tetrahydropentalene core. Overall, this intricate and unprecedented transformation comprises five carbon‐carbon bond formations in a single reaction.
Collapse
Affiliation(s)
- Max Hasenbeck
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Tizian Müller
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Arthur Averdunk
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Jonathan Becker
- Institut für Anorganische und Analytische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Urs Gellrich
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| |
Collapse
|
4
|
Affiliation(s)
- Urs Gellrich
- Institut für Organische Chemie Justus-Liebig-Universität Gießen Heinrich-Buff-Ring-17 35392 Gießen Germany
| |
Collapse
|
5
|
Wang G, Su X, Gao L, Liu X, Li G, Li S. Borane-catalyzed selective dihydrosilylation of terminal alkynes: reaction development and mechanistic insight. Chem Sci 2021; 12:10883-10892. [PMID: 34476068 PMCID: PMC8372554 DOI: 10.1039/d1sc02769g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/13/2021] [Indexed: 12/25/2022] Open
Abstract
Here, we describe simple B(C6F5)3-catalyzed mono- and dihydrosilylation reactions of terminal alkynes by using a silane-tuned chemoselectivity strategy, affording vinylsilanes and unsymmetrical geminal bis(silanes). This strategy is applicable to the dihydrosilylation of both aliphatic and aryl terminal alkynes with different silane combinations. Gram-scale synthesis and conducting the reaction without the exclusion of air and moisture demonstrate the practicality of this methodology. The synthetic utility of the resulting products was further highlighted by the structural diversification of geminal bis(silanes) through transforming the secondary silane into other silyl groups. Comprehensive theoretical calculations combined with kinetical isotope labeling studies have shown that a prominent kinetic differentiation between the hydrosilylation of alkynes and vinylsilane is responsible for the chemoselective construction of unsymmetrical 1,1-bis(silanes). A B(C6F5)3/silane-based system enables the chemoselective dihydrosilylation of terminal alkynes. Using a combination of different types of hydrosilanes, a series of unsymmetrical or symmetrical 1,1-bis(silanes) could be constructed.![]()
Collapse
Affiliation(s)
- Guoqiang Wang
- Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Xiaoshi Su
- Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Liuzhou Gao
- Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Xueting Liu
- Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Guoao Li
- Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Shuhua Li
- Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| |
Collapse
|
6
|
Shibuya M, Matsuda M, Yamamoto Y. 1,2-Carbopentafluorophenylation of Alkynes: The Metallomimetic Pull-Push Reactivity of Tris(pentafluorophenyl)borane. Chemistry 2021; 27:8822-8831. [PMID: 33860597 DOI: 10.1002/chem.202101090] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Indexed: 12/26/2022]
Abstract
We report the novel single-step 1,2-dicarbofunctionalization of an arylacetylene with an allylsilane and tris(pentafluorophenyl)borane [B(C6 F5 )3 ] involving C-C bond formation with C-H bond scission at the β-position to the silicon atom of an allylsilane and B→C migration of a C6 F5 group. The 1,2-carbopentafluorophenylation occurs smoothly without the requirement for a catalyst or heating. Mechanistic studies suggest that the metallomimetic "pull-push" reactivity of B(C6 F5 )3 imparts consecutive electrophilic and nucleophilic characteristics to the benzylic carbon of the arylacetylene. Subsequent photochemical 6π-electrocyclization affords tetrafluoronaphthalenes, which are important in the pharmaceutical and materials sciences. Owing to the unique reactivity of B(C6 F5 )3 , the 1,2-carbopentafluorophenylation using 2-substituted furan proceeded with ring opening, and the reaction using silyl enolates formed a C-C bond with C-O bond scission at the silyloxy-substituted carbon.
Collapse
Affiliation(s)
- Masatoshi Shibuya
- Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan
| | - Miki Matsuda
- Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan
| | - Yoshihiko Yamamoto
- Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan
| |
Collapse
|
7
|
Hasenbeck M, Wech F, Averdunk A, Becker J, Gellrich U. Indene formation upon borane-induced cyclization of arylallenes, 1,1-carboboration, and retro-hydroboration. Chem Commun (Camb) 2021; 57:5518-5521. [PMID: 33955432 DOI: 10.1039/d1cc01750k] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
We herein report the reaction of arylallenes with tris(pentafluorophenyl)borane that yields pentafluorophenyl substituted indenes. The tris(pentafluorophenyl)borane induces the cyclization of the allene and transfers a pentafluorophenyl ring in the course of this reaction. A Hammett plot analysis and DFT computations indicate a 1,1-carboboration to be the C-C bond-forming step.
Collapse
Affiliation(s)
- Max Hasenbeck
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392 Gießen, Germany.
| | - Felix Wech
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392 Gießen, Germany.
| | - Arthur Averdunk
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392 Gießen, Germany.
| | - Jonathan Becker
- Institut für Analytische und Anorganische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, Gießen 35392, Germany
| | - Urs Gellrich
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392 Gießen, Germany.
| |
Collapse
|
8
|
Chen C, Daniliuc CG, Mück-Lichtenfeld C, Kehr G, Erker G. A rare olefin 1,1-carboboration reaction opens a synthetic pathway to an unusually structured frustrated Lewis pair. Chem Commun (Camb) 2020; 56:8806-8809. [PMID: 32626861 DOI: 10.1039/d0cc01255f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
(2,6-Dimesitylphenyl)P(vinyl)25d reacts with HB(C6F5)2 in a sequence involving a rare example of a 1,1-carboboration of an olefin to give the borylated tetrahydrophosphole derivative 6d. Compound 6d is an active frustrated Lewis pair that splits dihydrogen under mild conditions and serves as a metal-free hydrogenation catalyst. It also adds to carbon dioxide. Compound 6d serves as an intermediate in the HB(C6F5)2 catalyzed aryl(divinyl)phosphane (5d) to dihydrophosphole conversion.
Collapse
Affiliation(s)
- Chaohuang Chen
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany.
| | | | | | | | | |
Collapse
|
9
|
Bismuto A, Nichol GS, Duarte F, Cowley MJ, Thomas SP. Characterization of the Zwitterionic Intermediate in 1,1-Carboboration of Alkynes. Angew Chem Int Ed Engl 2020; 59:12731-12735. [PMID: 32343867 DOI: 10.1002/anie.202003468] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Indexed: 11/12/2022]
Abstract
The reaction of a Lewis acidic borane with an alkyne is a key step in a diverse range of main group transformations. Alkyne 1,1-carboboration, the Wrackmeyer reaction, is an archetypal transformation of this kind. 1,1-Carboboration has been proposed to proceed through a zwitterionic intermediate. We report the isolation and spectroscopic, structural and computational characterization of the zwitterionic intermediates generated by reaction of B(C6 F5 )3 with alkynes. The stepwise reactivity of the zwitterion provides new mechanistic insight for 1,1-carboboration and wider B(C6 F5 )3 catalysis. Making use of intramolecular stabilization by a ferrocene substituent, we have characterized the zwitterionic intermediate in the solid state and diverted reactivity towards alkyne cyclotrimerization.
Collapse
Affiliation(s)
- Alessandro Bismuto
- EaStCHEM, School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Gary S Nichol
- EaStCHEM, School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Fernanda Duarte
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Michael J Cowley
- EaStCHEM, School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Stephen P Thomas
- EaStCHEM, School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| |
Collapse
|
10
|
Bismuto A, Nichol GS, Duarte F, Cowley MJ, Thomas SP. Characterization of the Zwitterionic Intermediate in 1,1‐Carboboration of Alkynes. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202003468] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Alessandro Bismuto
- EaStCHEM School of Chemistry University of Edinburgh Joseph Black Building David Brewster Road Edinburgh EH9 3FJ UK
| | - Gary S. Nichol
- EaStCHEM School of Chemistry University of Edinburgh Joseph Black Building David Brewster Road Edinburgh EH9 3FJ UK
| | - Fernanda Duarte
- Chemistry Research Laboratory University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - Michael J. Cowley
- EaStCHEM School of Chemistry University of Edinburgh Joseph Black Building David Brewster Road Edinburgh EH9 3FJ UK
| | - Stephen P. Thomas
- EaStCHEM School of Chemistry University of Edinburgh Joseph Black Building David Brewster Road Edinburgh EH9 3FJ UK
| |
Collapse
|
11
|
Abstract
The study of main-group molecules that behave and react similarly to transition-metal (TM) complexes has attracted significant interest in recent decades. Most notably, the attractive idea of replacing the all-too-often rare and costly metals from catalysis has motivated efforts to develop main-group-element-mediated reactions. Main-group elements, however, lack the electronic flexibility of TM complexes that arises from combinations of empty and filled d orbitals and that seem ideally suited to bind and activate many substrates. In this review, we look at boron, an element that despite its nonmetal nature, low atomic weight, and relative redox staticity has achieved great milestones in terms of TM-like reactivity. We show how in interelement cooperative systems, diboron molecules, and hypovalent complexes the fifth element can acquire a truly metallomimetic character. As we discuss, this character is powerfully demonstrated by the reactivity of boron-based molecules with H2, CO, alkynes, alkenes and even with N2.
Collapse
|
12
|
Hasenbeck M, Müller T, Gellrich U. Metal-free gem selective dimerization of terminal alkynes catalyzed by a pyridonate borane complex. Catal Sci Technol 2019. [DOI: 10.1039/c9cy00253g] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The metal-free dimerization of alkynes catalyzed by a pyridonate borane complex via a 1,2-carboration is reported.
Collapse
Affiliation(s)
- Max Hasenbeck
- Institute of Organic Chemistry
- Justus-Liebig University
- 35392 Giessen
- Germany
| | - Tizian Müller
- Institute of Organic Chemistry
- Justus-Liebig University
- 35392 Giessen
- Germany
| | - Urs Gellrich
- Institute of Organic Chemistry
- Justus-Liebig University
- 35392 Giessen
- Germany
| |
Collapse
|
13
|
Tsao FA, Sathaseevan A, Zhu H, Grimme S, Erker G, Stephan DW. Stoichiometric and catalytic isomerization of alkenylboranes using bulky Lewis bases. Chem Commun (Camb) 2017; 53:9458-9461. [PMID: 28795707 DOI: 10.1039/c7cc04904h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
1,1-Carboboration of alkynes with boranes R'B(C6F5)2 (R' = (CH2)3Ph, C6F5) affords mixtures of the E and Z isomers of RCH = CR'B(C6F5)2 (R = (CH2)2Me, (CH2)3Me, (CH2)2Ph, CH2CHMe2, CHMe2, CMe3, CH2OMe, CH2N(CO)2C6H4), treatment of these alkenylboranes with stoichiometric or catalytic amounts of tBu2PH or other donors are shown to induce isomerization. The proposed mechanism involving a zwitterionic borataalkene intermediate is supported by computations.
Collapse
Affiliation(s)
- Fu An Tsao
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, Ontario M5S3H6, Canada.
| | | | | | | | | | | |
Collapse
|
14
|
Lawson JR, Wilkins LC, Melen RL. Tris(2,4,6-trifluorophenyl)borane: An Efficient Hydroboration Catalyst. Chemistry 2017; 23:10997-11000. [PMID: 28686789 PMCID: PMC5577513 DOI: 10.1002/chem.201703109] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Indexed: 01/03/2023]
Abstract
The metal-free catalyst tris(2,4,6-trifluorophenyl)borane has demonstrated its extensive applications in the 1,2-hydroboration of numerous unsaturated reagents, namely alkynes, aldehydes and imines, consisting of a wide array of electron-withdrawing and donating functionalities. A range of over 50 borylated products are reported, with many reactions proceeding with low catalyst loading under ambient conditions. These pinacol boronate esters, in the case of aldehydes and imines, can be readily hydrolyzed to leave the respective alcohol and amine, whereas alkynyl substrates result in vinyl boranes. This is of great synthetic use to the organic chemist.
Collapse
Affiliation(s)
- James R Lawson
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, Cymru/Wales, CF10 3AT, UK
| | - Lewis C Wilkins
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, Cymru/Wales, CF10 3AT, UK
| | - Rebecca L Melen
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, Cymru/Wales, CF10 3AT, UK
| |
Collapse
|
15
|
Jian Z, Krupski S, Škoch K, Kehr G, Daniliuc CG, Císařová I, Štěpnička P, Erker G. Phosphine–Borane Frustrated Lewis Pairs Derived from a 1,1′-Disubstituted Ferrocene Scaffold: Synthesis and Hydrogenation Catalysis. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00363] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhongbao Jian
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse
40, 48149 Münster, Germany
| | - Sergei Krupski
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse
40, 48149 Münster, Germany
| | - Karel Škoch
- Department of Inorganic Chemistry,
Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic
| | - Gerald Kehr
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse
40, 48149 Münster, Germany
| | - Constantin G. Daniliuc
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse
40, 48149 Münster, Germany
| | - Ivana Císařová
- Department of Inorganic Chemistry,
Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic
| | - Petr Štěpnička
- Department of Inorganic Chemistry,
Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic
| | - Gerhard Erker
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse
40, 48149 Münster, Germany
| |
Collapse
|
16
|
Habraken ERM, Mens LC, Nieger M, Lutz M, Ehlers AW, Slootweg JC. Reactivity of the geminal phosphinoborane tBu2PCH2BPh2 towards alkynes, nitriles, and nitrilium triflates. Dalton Trans 2017; 46:12284-12292. [DOI: 10.1039/c7dt02570j] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The reactivity of the geminal phosphinoborane tBu2PCH2BPh2 towards terminal alkynes, nitriles and nitrilium salts is investigated.
Collapse
Affiliation(s)
- Evi R. M. Habraken
- Van ‘t Hoff Institute for Molecular Sciences
- University of Amsterdam
- 1090 GD Amsterdam
- The Netherlands
| | - Lars C. Mens
- Van ‘t Hoff Institute for Molecular Sciences
- University of Amsterdam
- 1090 GD Amsterdam
- The Netherlands
| | - Martin Nieger
- Department of Chemistry
- University of Helsinki
- Helsinki
- Finland
| | - Martin Lutz
- Crystal and Structural Chemistry
- Bijvoet Center for Biomolecular Research
- Utrecht University
- 3584 CH Utrecht
- The Netherlands
| | - Andreas W. Ehlers
- Van ‘t Hoff Institute for Molecular Sciences
- University of Amsterdam
- 1090 GD Amsterdam
- The Netherlands
- Department of Chemistry
| | - J. Chris Slootweg
- Van ‘t Hoff Institute for Molecular Sciences
- University of Amsterdam
- 1090 GD Amsterdam
- The Netherlands
| |
Collapse
|
17
|
Tussing S, Ohland M, Wicker G, Flörke U, Paradies J. Borane-catalyzed indole synthesis through intramolecular hydroamination. Dalton Trans 2017; 46:1539-1545. [DOI: 10.1039/c6dt04725d] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Catalytic metal-free intramolecular hydroamination for the synthesis of indoles and tetrahydroisoquinolines was achieved.
Collapse
Affiliation(s)
- Sebastian Tussing
- Institute of Organic Chemistry
- University of Paderborn
- D-33098 Paderborn
- Germany
| | - Miriam Ohland
- Institute of Organic Chemistry
- University of Paderborn
- D-33098 Paderborn
- Germany
| | - Garrit Wicker
- Institute of Organic Chemistry
- University of Paderborn
- D-33098 Paderborn
- Germany
| | - Ulrich Flörke
- Institute of Inorganic Chemistry
- University of Paderborn
- D-33098 Paderborn
- Germany
| | - Jan Paradies
- Institute of Organic Chemistry
- University of Paderborn
- D-33098 Paderborn
- Germany
| |
Collapse
|
18
|
Özgün T, Chen GQ, Daniliuc CG, McQuilken AC, Warren TH, Knitsch R, Eckert H, Kehr G, Erker G. Unsaturated Vicinal Frustrated Lewis Pair Formation by Electrocyclic Ring Closure and Their Reaction with Nitric Oxide. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00627] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Thomas Özgün
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
| | - Guo-Qiang Chen
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
| | - Constantin G. Daniliuc
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
| | - Alison C. McQuilken
- Department
of Chemistry, Georgetown University, Box 571227, Washington, D.C. 20057-1227, United States
| | - Timothy H. Warren
- Department
of Chemistry, Georgetown University, Box 571227, Washington, D.C. 20057-1227, United States
| | - Robert Knitsch
- Institut
für Physikalische Chemie, Westfälische Wilhelms-Universität, Corrensstrasse 30, 48149 Münster, Germany
| | - Hellmut Eckert
- Institut
für Physikalische Chemie, Westfälische Wilhelms-Universität, Corrensstrasse 30, 48149 Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
| |
Collapse
|
19
|
Nie W, Sun G, Tian C, Borzov MV. B(C6F5)3-guided cyclotrimerization-rearrangement of phenylacetylene. Evidence of the (C6F5)3B−–C(H)=C+Ph intermediate in a 1,1-carboboration reaction. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2016. [DOI: 10.1515/znb-2016-0110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
In presence of 2,2,6,6-tetramethylpiperidinium ([TMPH]+) chlorotris(pentafluorophenyl)borate ([TMPH]+[ClB(C6F5)3]−, 3), phenylacetylene undergoes an unusual cyclotrimerization-rearrangement leading to tris(pentafluorophenyl)(3,4,5-triphenylphenyl)borate anion (1) as a minor product which can be isolated and purified in a form of salts [1·(TMPH)
n
·Cl
(
n
–1)] (n=3 or 5). A variable temperature and concentration NMR spectroscopy study of 3 in CDCl3 unambiguously demonstrated its ability to liberate free B(C6F5)3, which initiates cyclotrimerization and guides rearrangements towards formation of the tetraarylborate anion 1. For the previously studied “spectator” reaction between phenylacetylene and B(C6F5)3 in CDCl3, 1H, 19F, and 11B NMR-spectral evidence of the (C6F5)3B−–C(H)=C+Ph zwitterionic intermediate of the 1,1-carboboration reaction has been demonstrated. The crystal structures of [1·(TMPH)
3
·Cl
2], the salt 3, and a 1:1 adduct of 1,3,5-tris(4-fluorophenyl)benzene and 2,4,6-tris(pentafluorophenyl)-1,3,5,2,4,6-trioxatriborinane (2) have been established by X-ray diffraction analysis.
Collapse
Affiliation(s)
- Wanli Nie
- Sichuan Key Laboratory of Natural Products and Small Molecule Synthesis, Chemical Department of Leshan Normal University, Binhe rd. 778, Leshan 614000, Sichuan province, P.R. China
| | - Guofeng Sun
- Sichuan Key Laboratory of Natural Products and Small Molecule Synthesis, Chemical Department of Leshan Normal University, Binhe rd. 778, Leshan 614000, Sichuan province, P.R. China
| | - Chong Tian
- Sichuan Key Laboratory of Natural Products and Small Molecule Synthesis, Chemical Department of Leshan Normal University, Binhe rd. 778, Leshan 614000, Sichuan province, P.R. China
| | - Maxim V. Borzov
- Sichuan Key Laboratory of Natural Products and Small Molecule Synthesis, Chemical Department of Leshan Normal University, Binhe rd. 778, Leshan 614000, Sichuan province, P.R. China , Tel.: +86 182 8333 6984, Fax: +86 833 2276022
| |
Collapse
|
20
|
Kohrt S, Kehr G, Daniliuc CG, Rojas RS, Rieger B, Troll C, Erker G. Borata-Alkene Derived Syntheses of (F5C6)2B-Substituted Bis(indenyl) Group 4 Metal Complexes. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00427] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sonja Kohrt
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität, Corrensstraße 40, 48149 Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität, Corrensstraße 40, 48149 Münster, Germany
| | - Constantin G. Daniliuc
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität, Corrensstraße 40, 48149 Münster, Germany
| | - René S. Rojas
- Departamento
de Química Inorgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile
| | - Bernhard Rieger
- WACKER-Lehrstuhl
für Makromolekulare Chemie, Technische Universität München, Lichtenbergstraße 4, 85748 Garching bei München, Germany
| | - Carsten Troll
- WACKER-Lehrstuhl
für Makromolekulare Chemie, Technische Universität München, Lichtenbergstraße 4, 85748 Garching bei München, Germany
| | - Gerhard Erker
- Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität, Corrensstraße 40, 48149 Münster, Germany
| |
Collapse
|
21
|
Tamke S, Qu ZW, Sitte NA, Flörke U, Grimme S, Paradies J. Cycloisomerisierung von 1,5-Eninen über eine 5-endo-dig- Cyclisierungs-Protodeborylierungs-Sequenz mit einem frustrierten Lewis-Paar als Katalysator. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201511921] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sergej Tamke
- Institut für Organische Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Deutschland
| | - Zheng-Wang Qu
- Mulliken Center for Theoretical Chemistry; Institut für Physikalische und Theoretische Chemie; Universität Bonn; Beringstraße 4 53115 Bonn Deutschland
| | - Nikolai A. Sitte
- Institut für Organische Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Deutschland
| | - Ulrich Flörke
- Institut für Anorganische und Analytische Chemie; Universität Paderborn; Deutschland
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry; Institut für Physikalische und Theoretische Chemie; Universität Bonn; Beringstraße 4 53115 Bonn Deutschland
| | - Jan Paradies
- Institut für Organische Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Deutschland
| |
Collapse
|
22
|
Tamke S, Qu ZW, Sitte NA, Flörke U, Grimme S, Paradies J. Frustrated Lewis Pair-Catalyzed Cycloisomerization of 1,5-Enynes via a 5-endo-dig Cyclization/Protodeborylation Sequence. Angew Chem Int Ed Engl 2016; 55:4336-9. [PMID: 26939012 DOI: 10.1002/anie.201511921] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 01/31/2016] [Indexed: 11/08/2022]
Abstract
The first frustrated Lewis pair-catalyzed cycloisomerization of a series of 1,5-enynes was developed. The reaction proceeds via the π-activation of the alkyne and subsequent 5-endo-dig cyclization with the adjacent alkene. The presence of PPh3 was of utmost importance on the one hand to prevent side reactions (for example, 1,1-carboboration) and on the other hand for the efficient protodeborylation to achieve the catalytic turnover. The mechanism is explained on the basis of quantum-chemical calculations, which are in full agreement with the experimental observations.
Collapse
Affiliation(s)
- Sergej Tamke
- Institute of Organic Chemistry, University of Paderborn, Warburger Strasse 100, 33098, Paderborn, Germany
| | - Zheng-Wang Qu
- Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, University of Bonn, Beringstrasse 4, 53115, Bonn, Germany
| | - Nikolai A Sitte
- Institute of Organic Chemistry, University of Paderborn, Warburger Strasse 100, 33098, Paderborn, Germany
| | - Ulrich Flörke
- Institute of Inorganic and Analytical Chemistry, University of Paderborn, Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, University of Bonn, Beringstrasse 4, 53115, Bonn, Germany.
| | - Jan Paradies
- Institute of Organic Chemistry, University of Paderborn, Warburger Strasse 100, 33098, Paderborn, Germany.
| |
Collapse
|
23
|
McGough JS, Butler SM, Cade IA, Ingleson MJ. Highly selective catalytic trans-hydroboration of alkynes mediated by borenium cations and B(C 6F 5) 3. Chem Sci 2016; 7:3384-3389. [PMID: 29997833 PMCID: PMC6006955 DOI: 10.1039/c5sc04798f] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 02/12/2016] [Indexed: 11/27/2022] Open
Abstract
Transition metal free alkyne trans-hydroboration is achieved using strong boron electrophiles in the presence of a B–H moiety.
The trans-hydroboration of terminal alkynes mediated by borenium cations [NHC(9-BBN)]+ (NHC = N-heterocyclic carbene, 9-BBN = 9-borabicyclo(3.3.1)nonane) exclusively affords Z-vinylboranes. NHCs and chelating dialkyl substituents on the borenium cation and “non”-basic anions were essential to preclude alternative reactions including dehydroboration. Deuterium labelling studies indicate the mechanism involves addition of the boron electrophile to the alkyne and transfer of hydride to the opposite face of the activated alkyne. trans-Hydroboration proceeds with only catalytic amounts of B(C6F5)3 or [Ph3C][B(C6F5)4] to activate the (NHC)9-BBN(H) precursor with the borenium regenerated in the hydride transfer step. The NHC can be removed from the trans-hydroborated products by the addition of Et2O–BF3 providing access to vinylBBN species effective for Suzuki–Miyaura couplings to generate Z-alkenes. Combinations of catalytic B(C6F5)3 and stoichiometric [HB(C6F5)3]– also lead to trans-hydroboration of terminal alkynes to form Z-isomers of [arylCH
Created by potrace 1.16, written by Peter Selinger 2001-2019
]]>
CHB(C6F5)3]–.
Collapse
Affiliation(s)
- John S McGough
- University of Manchester , Oxford Road , Manchester M13 9PL. , UK .
| | - Samuel M Butler
- University of Manchester , Oxford Road , Manchester M13 9PL. , UK .
| | - Ian A Cade
- University of Manchester , Oxford Road , Manchester M13 9PL. , UK .
| | | |
Collapse
|
24
|
Klose A, Kehr G, Daniliuc CG, Erker G. Phosphole formation by 1,1-carboboration – reactions of bis-alkynyl phosphanes with a frustrated P/B Lewis pair. Dalton Trans 2016; 45:2023-30. [DOI: 10.1039/c5dt03055b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The reaction of arylbis(alkynyl)phosphanes with the frustrated P/B Lewis pair mes2PCH2CH2B(C6F5)2gives phosphane/borane functionalized phospholes by a sequence of 1,1-carboboration reactions.
Collapse
Affiliation(s)
- Annika Klose
- Organisch-Chemisches Institut
- 48149 Münster
- Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut
- 48149 Münster
- Germany
| | | | | |
Collapse
|
25
|
Hansmann MM, Melen RL, Rudolph M, Rominger F, Wadepohl H, Stephan DW, Hashmi ASK. Cyclopropanation/Carboboration Reactions of Enynes with B(C6F5)3. J Am Chem Soc 2015; 137:15469-77. [PMID: 26580316 DOI: 10.1021/jacs.5b09311] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Stoichiometric reaction of B(C6F5)3 with 1,6-enynes is shown to proceed via initial cyclopropanation and formal 1,1-carboboration. Depending on the substitution on the alkene moiety, subsequent ring-opening of the cyclopropane affords either cyclopentane or cyclohexane derivatives in which the C6F5 and B(C6F5)2 adopt a 1,4-positioning. Mechanistically, this transformation involves π-activation of the alkyne moiety, which triggers cyclopropanation, followed by carboboration. Both the cyclopropanation and subsequent ring-opening are shown to be stereospecific. Both cyclopropanation and 1,4-carboborated products were employed as Lewis acid components in frustrated Lewis pair activation of H2 and CO2.
Collapse
Affiliation(s)
- Max M Hansmann
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Rebecca L Melen
- School of Chemistry, Cardiff University , Main Building, Cardiff, CF10 3AT, Cymru/Wales, U.K
| | - Matthias Rudolph
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Frank Rominger
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Hubert Wadepohl
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Douglas W Stephan
- Department of Chemistry, University of Toronto , 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada
| | - A Stephen K Hashmi
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.,Chemistry Department, Faculty of Science, King Abdulaziz University (KAU) , Jeddah 21589, Saudi Arabia
| |
Collapse
|
26
|
Rosorius C, Möricke J, Wibbeling B, McQuilken AC, Warren TH, Daniliuc CG, Kehr G, Erker G. Frustrated Lewis Pair Chemistry Derived from Bulky Allenyl and Propargyl Phosphanes. Chemistry 2015; 22:1103-13. [DOI: 10.1002/chem.201502493] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 09/14/2015] [Indexed: 11/07/2022]
Affiliation(s)
- Christoph Rosorius
- Organisch-Chemisches Institut; Universität Münster; Corrensstraße 40 48149 Münster Germany
| | - Jennifer Möricke
- Organisch-Chemisches Institut; Universität Münster; Corrensstraße 40 48149 Münster Germany
| | - Birgit Wibbeling
- Organisch-Chemisches Institut; Universität Münster; Corrensstraße 40 48149 Münster Germany
| | - Alison C. McQuilken
- Department of Chemistry; Georgetown University; 37th and O Streets NW Washington DC 20057-1227 USA
| | - Timothy H. Warren
- Department of Chemistry; Georgetown University; 37th and O Streets NW Washington DC 20057-1227 USA
| | - Constantin G. Daniliuc
- Organisch-Chemisches Institut; Universität Münster; Corrensstraße 40 48149 Münster Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut; Universität Münster; Corrensstraße 40 48149 Münster Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut; Universität Münster; Corrensstraße 40 48149 Münster Germany
| |
Collapse
|
27
|
Kehr G, Erker G. Advanced 1,1-carboboration reactions with pentafluorophenylboranes. Chem Sci 2015; 7:56-65. [PMID: 28757997 PMCID: PMC5508682 DOI: 10.1039/c5sc03282b] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 10/07/2015] [Indexed: 01/06/2023] Open
Abstract
The advanced 1,1-carboboration reaction converts alkynes to alkenylboranes and allows a variety of sequential ring forming reactions of bis(alkynyl) compounds.
The 1,1 carboboration reaction of a variety of metal-substituted alkynes with simple trialkylboranes R3B yields the respective alkenylboranes (Wrackmeyer reaction). The use of the strongly electrophilic R-B(C6F5)2 reagents allows for much milder reaction conditions and gives good yields of the respective bulky alkenylboranes from conventional terminal alkynes by means of 1,2-hydride migration. Even internal alkynes undergo 1,1-carboboration with the R-B(C6F5)2 reagents, in this case yielding alkenylboranes by means of C–C bond cleavage. Phosphorus, sulfur or even boron containing substituents can serve as the migrating alkynyl substituents in the advanced 1,1-carboboration reactions using the R-B(C6F5)2 reagents. Sequential 1,1-carboboration of geminal bis(alkynyl) derivatives of these elements with the R-B(C6F5)2 boranes yields boryl substituted phospholes, thiophenes or even boroles in quite a variety. Vicinal bis(alkynyl)arenes or heteroarene substrates undergo benzannulation reactions in this way. Many of the -B(C6F5)2 substituted 1,1-carboboration products can be used as reagents in cross coupling reactions. A recently disclosed organometallic analogue, namely a 1,1-carbozirconation reaction is described.
Collapse
Affiliation(s)
- Gerald Kehr
- Organisch-Chemisches Institut , Universität Münster , Corrensstraße 40 , D-48149 Münster , Germany .
| | - Gerhard Erker
- Organisch-Chemisches Institut , Universität Münster , Corrensstraße 40 , D-48149 Münster , Germany .
| |
Collapse
|
28
|
Feldmann A, Kehr G, Daniliuc CG, Mück-Lichtenfeld C, Erker G. Functionalization of Intramolecular Frustrated Lewis Pairs by 1,1-Carboboration with Conjugated Enynes. Chemistry 2015; 21:12456-64. [PMID: 26284948 DOI: 10.1002/chem.201502278] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Indexed: 11/11/2022]
Abstract
The vicinal P/B frustrated Lewis pair (FLP) Mes2PCH2CH2B(C6F5)2 undergoes 1,1-carboboration reactions with the Me3Si-substituted enynes to give ring-enlarged functionalized C3-bridged P/B FLPs. These serve as active FLPs in the activation of dihydrogen to give the respective zwitterionic [P]H(+)/[B]H(-) products. One such product shows activity as a metal-free catalyst for the hydrogenation of enamines or a bulky imine. The ring-enlarged FLPs contain dienylborane functionalities that undergo "bora-Nazarov"-type ring-closing rearrangements upon photolysis. A DFT study had shown that the dienylborane cyclization of such systems itself is endothermic, but a subsequent C6F5 migration is very favorable. Furthermore, substituted 2,5-dihydroborole products are derived from cyclization and C6F5 migration from the photolysis reaction. In the case of the six-membered annulation product, a subsequent stereoisomerization reaction takes place and the resultant compound undergoes a P/B FLP 1,2-addition reaction with a terminal alkyne with rearrangement.
Collapse
Affiliation(s)
- Andreas Feldmann
- Organisch-Chemisches Institut der Universität Münster, Corrensstr. 40, 48149 Münster (Germany)
| | - Gerald Kehr
- Organisch-Chemisches Institut der Universität Münster, Corrensstr. 40, 48149 Münster (Germany)
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut der Universität Münster, Corrensstr. 40, 48149 Münster (Germany)
| | | | - Gerhard Erker
- Organisch-Chemisches Institut der Universität Münster, Corrensstr. 40, 48149 Münster (Germany).
| |
Collapse
|
29
|
Ge F, Türkyilmaz F, Daniliuc CG, Siedow M, Eckert H, Kehr G, Erker G. A 1,1-Carboboration Route to Bora-Nazarov Systems. Chem Asian J 2015. [PMID: 26223464 DOI: 10.1002/asia.201500636] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Hydroboration of the conjugated enynes 1 a and 1 b with Piers' borane [HB(C6F5)2] gave the respective dienylboranes trans-2 c and trans-2 d. Their photolysis resulted in the formation of the dihydroborole products 3 c and 3 d. Both were converted to their pyridine adducts 5 c and 5 d, respectively. Compounds 3 c and 5 c,d were characterized by X-ray diffraction. The reaction of the bis(enynyl)boranes 6 a and 6 b with B(C6F5)3 resulted in the formation of the dihydroboroles 7 a and 7 b, respectively. This reaction is thought to proceed by 1,1-carboboration of one of the enynyl substituents at boron to generate the dienylborane intermediates 8 a/8 b, followed by thermally induced bora-Nazarov ring-closure and subsequent stabilizing 1,2-pentafluorophenyl group migration from boron to carbon. Compound 7 a was characterized by X-ray diffraction and solid-state (11)B NMR spectroscopy.
Collapse
Affiliation(s)
- Fang Ge
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, 48149, Münster, Germany
| | - Fatma Türkyilmaz
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, 48149, Münster, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, 48149, Münster, Germany
| | - Melanie Siedow
- Institut für Physikalische Chemie, Universität Münster, Corrensstraße 30, 48149, Münster, Germany
| | - Hellmut Eckert
- Institut für Physikalische Chemie, Universität Münster, Corrensstraße 30, 48149, Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, 48149, Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, 48149, Münster, Germany.
| |
Collapse
|
30
|
Pinkas J, Lamač M. Transformations of functional groups attached to cyclopentadienyl or related ligands in group 4 metal complexes. Coord Chem Rev 2015. [DOI: 10.1016/j.ccr.2015.03.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
31
|
Bähr A, Wilkins LC, Ollegott K, Kariuki BM, Melen RL. Σ- versus π-activation of alkynyl benzoates using B(C₆F₅)₃. Molecules 2015; 20:4530-47. [PMID: 25774488 PMCID: PMC6272168 DOI: 10.3390/molecules20034530] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 02/17/2015] [Accepted: 02/28/2015] [Indexed: 11/16/2022] Open
Abstract
We have prepared a range of alkynyl benzoates in high yields and have investigated their reactivities with the strong Lewis acid B(C6F5)3. In such molecules both σ-activation of the carbonyl and π-activation of the alkyne are possible. In contrast to the reactivity of propargyl esters with B(C6F5)3 which proceed via 1,2-addition of the ester and B(C6F5)3 across the alkyne, the inclusion of an additional CH2 spacer switches off the intramolecular cyclization and selective σ-activation of the carbonyl group is observed through adduct formation. This change in reactivity appears due to the instability of the species which would be formed through B(C6F5)3 activation of the alkyne.
Collapse
Affiliation(s)
- Alexander Bähr
- School of Chemistry, Main Building, Cardiff University, Cardiff CF10 3AT, Cymru/Wales, UK.
| | - Lewis C Wilkins
- School of Chemistry, Main Building, Cardiff University, Cardiff CF10 3AT, Cymru/Wales, UK.
| | - Kevin Ollegott
- School of Chemistry, Main Building, Cardiff University, Cardiff CF10 3AT, Cymru/Wales, UK.
| | - Benson M Kariuki
- School of Chemistry, Main Building, Cardiff University, Cardiff CF10 3AT, Cymru/Wales, UK.
| | - Rebecca L Melen
- School of Chemistry, Main Building, Cardiff University, Cardiff CF10 3AT, Cymru/Wales, UK.
| |
Collapse
|
32
|
Ren X, Li G, Wei S, Du H. Facile Development of Chiral Alkenylboranes from Chiral Diynes for Asymmetric Hydrogenation of Silyl Enol Ethers. Org Lett 2015; 17:990-3. [DOI: 10.1021/acs.orglett.5b00085] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiaoyu Ren
- Beijing National Laboratory
for Molecular Sciences, CAS Key Laboratory of Molecular Recognition
and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Gen Li
- Beijing National Laboratory
for Molecular Sciences, CAS Key Laboratory of Molecular Recognition
and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Simin Wei
- Beijing National Laboratory
for Molecular Sciences, CAS Key Laboratory of Molecular Recognition
and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Haifeng Du
- Beijing National Laboratory
for Molecular Sciences, CAS Key Laboratory of Molecular Recognition
and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| |
Collapse
|
33
|
Eller C, Kehr G, Daniliuc CG, Stephan DW, Erker G. Thiophene synthesis via 1,1-carboboration. Chem Commun (Camb) 2015; 51:7226-9. [PMID: 25813555 DOI: 10.1039/c5cc01806d] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction of bis(tert-butylethynyl)sulfide with the boron Lewis acid reagents X–B(C6F5)2 (X = CH3, Cl, C6F5) in pentane at r.t. gave the respective borylated thiophenes in a sequence of 1,1-carboboration reactions.
Collapse
Affiliation(s)
- Christina Eller
- Organisch-Chemisches Institut der Universität Münster
- 48149 Münster
- Germany
- Department of Chemistry University of Toronto
- Toronto
| | - Gerald Kehr
- Organisch-Chemisches Institut der Universität Münster
- 48149 Münster
- Germany
| | | | | | - Gerhard Erker
- Organisch-Chemisches Institut der Universität Münster
- 48149 Münster
- Germany
| |
Collapse
|
34
|
Chen GQ, Kehr G, Daniliuc CG, Erker G. 1,1-Alkenylboration of diarylphosphino-enynes: convenient synthetic entry to vicinal P/B Lewis pairs at extended conjugated π-frameworks. Org Biomol Chem 2015; 13:764-9. [DOI: 10.1039/c4ob02134g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Alkenylboranes R-CHCH-B(C6F5)2 undergo carbon–carbon coupling by means of 1,1-alkenylboration with diarylphosphino-enynes to give conjugated hexatriene derivatives that bear a vicinal pair of B(C6F5)2 and PAr2 functionalities at the framework.
Collapse
Affiliation(s)
- Guo-Qiang Chen
- Organisch-Chemisches Institut
- Universität Münster
- Münster
- Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut
- Universität Münster
- Münster
- Germany
| | | | - Gerhard Erker
- Organisch-Chemisches Institut
- Universität Münster
- Münster
- Germany
| |
Collapse
|
35
|
Ge F, Kehr G, Daniliuc CG, Erker G. Reactions of Boroles Formed by 1,1-Carboboration. Organometallics 2014. [DOI: 10.1021/om501085j] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Fang Ge
- Organisch-Chemisches
Institut, Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches
Institut, Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany
| | - Constantin G. Daniliuc
- Organisch-Chemisches
Institut, Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches
Institut, Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany
| |
Collapse
|
36
|
Xu X, Kehr G, Daniliuc CG, Erker G. Formation of Unsaturated Vicinal Zr+/P Frustrated Lewis Pairs by the Unique 1,1-Carbozirconation Reactions. J Am Chem Soc 2014; 136:12431-43. [DOI: 10.1021/ja5068146] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Xin Xu
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany
| | - Constantin G. Daniliuc
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany
| |
Collapse
|
37
|
Abstract
The reaction of 8-(trimethylsiloxy)quinoline (QOTMS) with BCl3 and
(aryl)BCl2 forms QOBCl2 and QOBCl(aryl). The subsequent addition
of stoichiometric AlCl3 follows one of two paths, dependent on the steric demands of the
QO ligand and the electrophilicity of the resulting borenium cation. The phenyl- and
5-hexylthienylborenium cations, QOBPh+ and
QOBTh+, are formed, whereas QOBCl+ is
not. Instead, AlCl3 preferentially binds with QOBCl2 at oxygen,
forming QOBCl2⋅AlCl3, rather than abstracting chloride. A
modest increase in the steric demands around oxygen, by installing a methyl group at the 7-position
of the quinolato ligand, switches the reactivity with AlCl3 back to chloride abstraction,
allowing formation of QOBCl+. All the
prepared borenium cations are highly chlorophilic and exhibit significant interaction with
AlCl4− resulting in an equilibrium concentration of Lewis acidic
“AlCl3” species. The presence of
“AlCl3” species limits the alkyne substrates compatible with
these borenium systems, with reaction of
[QOBPh][AlCl4] with 1-pentyne exclusively
yielding the cyclotrimerised product, 1,3,5-tripropylbenzene. In contrast,
QOBPh+ and QOBTh+ systems effect the
syn-1,2-carboboration of 3-hexyne. DFT calculations at the
M06-2X/6-311G(d,p)/PCM(DCM) level confirm that the higher migratory aptitude of Ph versus Me leads
to a lower barrier to 1,2-carboboration relative to 1,1-carboboration.
Collapse
Affiliation(s)
- Ian A Cade
- School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL (UK)
| | | |
Collapse
|
38
|
Liedtke R, Scheidt F, Ren J, Schirmer B, Cardenas AJP, Daniliuc CG, Eckert H, Warren TH, Grimme S, Kehr G, Erker G. Frustrated Lewis Pair Modification by 1,1-Carboboration: Disclosure of a Phosphine Oxide Triggered Nitrogen Monoxide Addition to an Intramolecular P/B Frustrated Lewis Pair. J Am Chem Soc 2014; 136:9014-27. [DOI: 10.1021/ja5028293] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- René Liedtke
- Organisch-Chemisches
Institut, Universität Münster, Corrensstrasse 40, Münster 48149, Germany
| | - Felix Scheidt
- Organisch-Chemisches
Institut, Universität Münster, Corrensstrasse 40, Münster 48149, Germany
| | - Jinjun Ren
- Institut
für Physikalische Chemie, Universität Münster, Corrensstrasse
30, Münster 48149, Germany
| | - Birgitta Schirmer
- Organisch-Chemisches
Institut, Universität Münster, Corrensstrasse 40, Münster 48149, Germany
| | - Allan Jay P. Cardenas
- Department
of Chemistry, Georgetown University, 37th and O Streets NW, Washington, DC 20057-1227, United States
| | - Constantin G. Daniliuc
- Organisch-Chemisches
Institut, Universität Münster, Corrensstrasse 40, Münster 48149, Germany
| | - Hellmut Eckert
- Institut
für Physikalische Chemie, Universität Münster, Corrensstrasse
30, Münster 48149, Germany
| | - Timothy H. Warren
- Department
of Chemistry, Georgetown University, 37th and O Streets NW, Washington, DC 20057-1227, United States
| | - Stefan Grimme
- Mulliken
Center for Theoretical Chemistry, Institut für Physikalische
und Theoretische Chemie, Universität Bonn, Beringstrasse 4, Bonn 53115, Germany
| | - Gerald Kehr
- Organisch-Chemisches
Institut, Universität Münster, Corrensstrasse 40, Münster 48149, Germany
| | - Gerhard Erker
- Organisch-Chemisches
Institut, Universität Münster, Corrensstrasse 40, Münster 48149, Germany
| |
Collapse
|
39
|
Chen C, Harhausen M, Fukazawa A, Yamaguchi S, Fröhlich R, Daniliuc CG, Petersen JL, Kehr G, Erker G. The B(C6F5)3 boron Lewis acid route to arene-annulated pentalenes. Chem Asian J 2014; 9:1671-81. [PMID: 24683018 DOI: 10.1002/asia.201400096] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 02/13/2014] [Indexed: 11/09/2022]
Abstract
4,5-Dimethyl-1,2-bis(1-naphthylethynyl)benzene (12) undergoes a rapid multiple ring-closure reaction upon treatment with the strong boron Lewis acid B(C6F5)3 to yield the multiply annulated, planar conjugated π-system 13 (50 % yield). In the course of this reaction, a C6F5 group was transferred from boron to carbon. Treatment of 12 with CH3B(C6F5)2 proceeded similarly, giving a mixture of 13 (C6F5-transfer) and the product 15, which was formed by CH3-group transfer. 1,2-Bis(phenylethynyl)benzene (8 a) reacts similarly with CH3B(C6F5)2 to yield a mixture of the respective C6F5- and CH3-substituted dibenzopentalenes 10 a and 16. The reaction is thought to proceed through zwitterionic intermediates that exhibit vinyl cation reactivities. Some B(C6F5)3-substituted species (26, 27) consequently formed by in situ deprotonation upon treatment of the respective 1,2-bis(alkynyl)benzene starting materials (24, 8) with the frustrated Lewis pair B(C6F5)3/P(o-tolyl)3. The overall formation of the C6F5-substituted products formally require HB(C6F5)2 cleavage in an intermediate dehydroboration step. This was confirmed in the reaction of a thienylethynyl-containing starting material 21 with B(C6F5)3, which gave the respective annulated pentalene product 23 that had the HB(C6F5)2 moiety 1,4-added to its thiophene ring. Compounds 12-14, 23, and 26 were characterized by X-ray diffraction.
Collapse
Affiliation(s)
- Chao Chen
- Organisch Chemisches Institut der Universität Münster, Corrensstrasse 40, 48149 Münster (Germany)
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Paradies J. Metallfreie Hydrierung von ungesättigten Kohlenwasserstoffen mit molekularem Wasserstoff. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201309253] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
41
|
Paradies J. Metal-Free Hydrogenation of Unsaturated Hydrocarbons Employing Molecular Hydrogen. Angew Chem Int Ed Engl 2014; 53:3552-7. [DOI: 10.1002/anie.201309253] [Citation(s) in RCA: 218] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Indexed: 11/06/2022]
|
42
|
Ekkert O, Tuschewitzki O, Daniliuc CG, Kehr G, Erker G. Reaction of strongly electrophilic alkenylboranes with phosphanylalkynes: rare examples of intermolecular 1,1-alkenylboration reactions. Chem Commun (Camb) 2014; 49:6992-4. [PMID: 23807493 DOI: 10.1039/c3cc43294g] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Simple alkenylbis(pentafluorophenyl)boranes undergo 1,1-alkenylboration with phosphanylacetylenes to give phosphane-borane Lewis pairs with a conjugated diene backbone.
Collapse
Affiliation(s)
- Olga Ekkert
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany
| | | | | | | | | |
Collapse
|
43
|
Sajid M, Lawzer A, Dong W, Rosorius C, Sander W, Schirmer B, Grimme S, Daniliuc CG, Kehr G, Erker G. Carbonylation reactions of intramolecular vicinal frustrated phosphane/borane Lewis pairs. J Am Chem Soc 2013; 135:18567-74. [PMID: 24147963 DOI: 10.1021/ja408815k] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The intramolecular frustrated Lewis pair (FLP) Mes2PCH2CH2B(C6F5)2 4 adds cooperatively to carbon monoxide to form the five-membered heterocyclic carbonyl compound 5. The intramolecular FLP 7 contains an exo-3-B(C6F5)2 Lewis acid and an endo-2-PMes2 Lewis base functionality coordinated at the norbornane framework. This noninteracting FLP adds carbon monoxide in solution at -35 °C cooperatively to yield a five-membered heterocyclic FLP-carbonyl compound 8. In contrast, FLP 7 is carbonylated in a CO-doped argon matrix at 25 K to selectively form a borane carbonyl 9 without involvement of the adjacent phosphanyl moiety. The free FLP 7 was generated in the gas phase from its FLPH2 product 10. A DFT study has shown that the phosphonium hydrido borate zwitterion 10 is formed exergonically in solution but tends to lose H2 when brought into the gas phase.
Collapse
Affiliation(s)
- Muhammad Sajid
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität , Corrensstraße 40, 48149 Münster, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Xu X, Kehr G, Daniliuc CG, Erker G. 1,1-Carbozirconation: Unusual Reaction of an Alkyne with a Methyl Zirconocene Cation and Subsequent Frustrated Lewis Pair Like Reactivity. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201307493] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
45
|
Xu X, Kehr G, Daniliuc CG, Erker G. 1,1-Carbozirconation: Unusual Reaction of an Alkyne with a Methyl Zirconocene Cation and Subsequent Frustrated Lewis Pair Like Reactivity. Angew Chem Int Ed Engl 2013; 52:13629-32. [DOI: 10.1002/anie.201307493] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Indexed: 11/05/2022]
|
46
|
|
47
|
Ekkert O, Kehr G, Daniliuc CG, Fröhlich R, Wibbeling B, Petersen JL, Erker G. Reaction of Unsaturated Vicinal Phosphane/Borane Frustrated Lewis Pairs with Benzaldehyde. Z Anorg Allg Chem 2013. [DOI: 10.1002/zaac.201300421] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
48
|
Yu J, Kehr G, Daniliuc CG, Erker G. Reaction of Diphenylphosphanylacetylene with RB(C6F5)2 Reagents: Evidence for a Remarkable Sequence of Synergistic Frustrated Lewis Pair Addition Reactions. Inorg Chem 2013; 52:11661-8. [DOI: 10.1021/ic402139g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jiangang Yu
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse
40, 48149 Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse
40, 48149 Münster, Germany
| | - Constantin G. Daniliuc
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse
40, 48149 Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse
40, 48149 Münster, Germany
| |
Collapse
|
49
|
Melen RL, Hansmann MM, Lough AJ, Hashmi ASK, Stephan DW. Cyclisation versus 1,1-Carboboration: Reactions of B(C6F5)3with Propargyl Amides. Chemistry 2013; 19:11928-38. [DOI: 10.1002/chem.201301899] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Indexed: 11/12/2022]
|
50
|
Ge F, Kehr G, Daniliuc CG, Erker G. Unusual Pathway Taken in the Reaction of Bis(alkynyl)diisopropylaminoboranes with B(C6F5)3. Chem Asian J 2013; 8:2227-34. [DOI: 10.1002/asia.201300536] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Indexed: 11/08/2022]
|