1
|
Leung VMY, Pook CM, Chan TC, Yeung YY. Trialkylphosphonium Oxoborate as C(sp 3 )-H Oxyanion Hole Catalyst for Diels-Alder Reaction. Chem Asian J 2024; 19:e202300981. [PMID: 38116878 DOI: 10.1002/asia.202300981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/19/2023] [Accepted: 12/19/2023] [Indexed: 12/21/2023]
Abstract
We have developed a catalytic protocol for Diels-Alder reaction using trialkylphosphonium oxoborates as oxyanion hole catalysts. The reaction can be operated under ambient conditions. Dienes could easily polymerize under acidic condition. Nonetheless, these acid-sensitive substrates are compatible with the catalytic protocol and the reaction scope covers a wide range of substrates.
Collapse
Affiliation(s)
- Vincent Ming-Yau Leung
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong Shatin, NT, Hong Kong, China
| | - Chun-Man Pook
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong Shatin, NT, Hong Kong, China
| | - Tsz-Chun Chan
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong Shatin, NT, Hong Kong, China
| | - Ying-Yeung Yeung
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong Shatin, NT, Hong Kong, China
| |
Collapse
|
2
|
Leung VMY, Wong HCF, Pook CM, Tse YLS, Yeung YY. Trialkylphosphonium oxoborates as C(sp 3)-H oxyanion holes and their application in catalytic chemoselective acetalization. Chem Sci 2023; 14:12684-12692. [PMID: 38020391 PMCID: PMC10646966 DOI: 10.1039/d3sc03081d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 10/15/2023] [Indexed: 12/01/2023] Open
Abstract
The use of trialkylphosphonium oxoborates (TOB) as catalysts is reported. The site-isolated borate counter anion in a TOB catalyst increases the availability of C(sp3)-H to interact with electron donor substrates. The catalytic protocol is applicable to a wide range of substrates in the acetalization reaction and provides excellent chemoselectivity in the acetalization over thioacetalization in the presence of alcohols and thiols, which is otherwise hard to achieve using typical acid catalysts. Experimental and computational studies revealed that the TOB catalysts have multiple preorganized C(sp3)-Hs that serve as a mimic of oxyanion holes, which can stabilize the oxyanion intermediates via multiple C(sp3)-H non-classical hydrogen bond interactions.
Collapse
Affiliation(s)
- Vincent Ming-Yau Leung
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong Shatin, NT Hong Kong China
| | - Hong-Chai Fabio Wong
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong Shatin, NT Hong Kong China
| | - Chun-Man Pook
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong Shatin, NT Hong Kong China
| | - Ying-Lung Steve Tse
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong Shatin, NT Hong Kong China
| | - Ying-Yeung Yeung
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong Shatin, NT Hong Kong China
| |
Collapse
|
3
|
Coughlin O, Krämer T, Benjamin SL. Cationic Triarylchlorostibonium Lewis Acids. Organometallics 2023; 42:339-346. [PMID: 36937787 PMCID: PMC10015551 DOI: 10.1021/acs.organomet.2c00426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Indexed: 02/22/2023]
Abstract
Organopnictogen cations show promise as powerful, tunable main-group Lewis acid catalysts. The synthesis, solid-state structures, and reactivity of a series of weakly coordinated triarylchlorostibonium salts [Ar3SbCl][B(C6F5)4] (Ar = Ph, 3-FC6H4, 4-FC6H4, 3,5-F2C6H3, 2,4,6-F3C6H2) are reported. The cation in each adopts a tetrahedral coordination environment of antimony, with near complete separation from the anion. Structural, computational, and reactivity studies reveal that the Lewis acidity of [Ar3SbCl]+ generally increases with increased fluorination of the Ar substituents, with a secondary quenching effect from para fluorination. [Ar3SbCl]+ is reduced to Ar3Sb in the presence of Et3SiH, and the mechanism of this reaction has been modeled computationally. Preliminary studies demonstrate that they are useful catalysts for the dimerization of 1,1-diphenylethylene and the Friedel-Crafts alkylation of benzene.
Collapse
Affiliation(s)
- Omar Coughlin
- Department
of Chemistry, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, U.K.
| | - Tobias Krämer
- Department
of Chemistry, Maynooth University, Maynooth, Co. Kildare W23 F2H6, Ireland
| | - Sophie L. Benjamin
- Department
of Chemistry, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, U.K.
| |
Collapse
|
4
|
Metal−free catalysis of the reductive amination of aldehydes using a phosphonium−doped porous aromatic framework. MOLECULAR CATALYSIS 2022. [DOI: 10.1016/j.mcat.2022.112600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
5
|
Sarkar P, Das S, Pati SK. Recent Advances in Group 14 and 15 Lewis Acids for Frustrated Lewis Pair Chemistry. Chem Asian J 2022; 17:e202200148. [PMID: 35320614 DOI: 10.1002/asia.202200148] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/22/2022] [Indexed: 11/10/2022]
Abstract
Frustrated Lewis pairs (FLP) which rely on the cooperative action of Lewis acids and Lewis bases, played a prominent role in the advancement of main-group catalysis. While the early days of FLP chemistry witnessed the dominance of boranes, there is a growing body of reports on alternative Lewis acids derived from groups 14 and 15. This short review focuses on the discovery of such non-boron candidates reported since 2015.
Collapse
Affiliation(s)
- Pallavi Sarkar
- Jawaharlal Nehru Centre for Advanced Scientific Research, Theoretical Sciences Unit, INDIA
| | - Shubhajit Das
- Jawaharlal Nehru Centre for Advanced Scientific Research, New Chemstry Unit, INDIA
| | - Swapan K Pati
- JNCASR, Theoretical Sciences Unit and New Chemistry Unit, Jakkur Campus, 560064, Bangalore, INDIA
| |
Collapse
|
6
|
Sarkar P, Das S, Pati SK. Investigating Tetrel-Based Neutral Frustrated Lewis Pairs for Hydrogen Activation. Inorg Chem 2021; 60:15180-15189. [PMID: 34590831 DOI: 10.1021/acs.inorgchem.1c01543] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tetrel Lewis acids are a prospective alternative to commonly employed neutral boranes in frustrated Lewis pair (FLP) chemistry. While cationic tetrylium Lewis acids, being isolobal and iso(valence)electronic, are a natural replacement to boranes, neutral tetrel Lewis acids allude as less trivial options due to the absence of a formally empty p orbital on the acceptor atom. Recently, a series of intramolecular geminal FLPs (C2F5)3E-CH2-P(tBu)2 (E = Si, Ge, Sn) featuring neutral tetrel atoms as acceptor sites has been reported for activation of small molecules including H2. In this work, through density functional theory computations, we elucidate the general mechanistic picture of H2 activation by this family of FLPs. Our findings reveal that the acceptor atom derives the required Lewis acidity utilizing the antibonding orbitals of its adjacent bonds with the individual contributions depending on the identity of the acceptor and the donor atoms. By varying the identity of the Lewis acid and Lewis base sites and attached substituents, we unravel their interplay on the energetics of the H2 activation. We find that switching the donor site from P to N significantly affects the synchronous nature of the bond breaking/formations along the reaction pathway, and as a result, N-bearing FLPs have a more favorable H2 activation profile than those with P. Our results are quantitatively discussed in detail within the framework of the activation-strain model of reactivity along with the energy-decomposition analysis method. Finally, the reductive elimination decomposition route pertinent to the plausible extension of the H2 activation to catalytic hydrogenation by these FLPs is also examined.
Collapse
Affiliation(s)
- Pallavi Sarkar
- Theoretical Sciences Unit, School of Advanced Materials (SAMat), Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Shubhajit Das
- Theoretical Sciences Unit, School of Advanced Materials (SAMat), Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Swapan K Pati
- Theoretical Sciences Unit, School of Advanced Materials (SAMat), Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| |
Collapse
|
7
|
Clarke JJ, Devaraj K, Bestvater BP, Kojima R, Eisenberger P, DeJesus JF, Crudden CM. Hydrosilylation and Mukaiyama aldol-type reaction of quinolines and hydrosilylation of imines catalyzed by a mesoionic carbene-stabilized borenium ion. Org Biomol Chem 2021; 19:6786-6791. [PMID: 34318834 DOI: 10.1039/d1ob01056e] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aldimines and ketimines containing electron-donating and electron-withdrawing groups can be hydrosilylated with borenium catalysts at as low as 1 mol% catalyst loading at room temperature, providing the corresponding secondary amines in excellent yields. Reactions with 2-phenylquinoline gave the 1,4-hydrosilylquinoline product selectively which can be further functionalized in a one-pot synthesis to give unique γ-amino alcohol derivatives. Control experiments suggest that the borenium ion catalyzes both the hydrosilylation and subsequent addition to the aldehyde.
Collapse
Affiliation(s)
- Joshua J Clarke
- Department of Chemistry, Queen's University, Chernoff Hall, Kingston, Ontario K7L 3N6, Canada.
| | | | | | | | | | | | | |
Collapse
|
8
|
Selective C–H fluoroalkylation of azines enabled by tailored phosphorus-based reagents. Chem 2021. [DOI: 10.1016/j.chempr.2021.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
9
|
Zhang X, Nottingham KG, Patel C, Alegre-Requena JV, Levy JN, Paton RS, McNally A. Phosphorus-mediated sp 2-sp 3 couplings for C-H fluoroalkylation of azines. Nature 2021; 594:217-222. [PMID: 33910228 DOI: 10.1038/s41586-021-03567-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/20/2021] [Indexed: 12/15/2022]
Abstract
Fluoroalkyl groups profoundly affect the physical properties of pharmaceuticals and influence almost all metrics associated with their pharmacokinetic and pharmacodynamic profile1-4. Drug candidates increasingly contain trifluoromethyl (CF3) and difluoromethyl (CF2H) groups, and the same trend in agrochemical development shows that the effect of fluoroalkylation translates across human, insect and plant life5,6. New fluoroalkylation reactions have undoubtedly stimulated this shift; however, methods that directly convert C-H bonds into C-CF2X groups (where X is F or H) in complex drug-like molecules are rare7-13. Pyridines are the most common aromatic heterocycles in pharmaceuticals14, but only one approach-via fluoroalkyl radicals-is viable for achieving pyridyl C-H fluoroalkylation in the elaborate structures encountered during drug development15-17. Here we develop a set of bench-stable fluoroalkylphosphines that directly convert the C-H bonds in pyridine building blocks, drug-like fragments and pharmaceuticals into fluoroalkyl derivatives. No preinstalled functional groups or directing groups are required. The reaction tolerates a variety of sterically and electronically distinct pyridines, and is exclusively selective for the 4-position in most cases. The reaction proceeds through initial formation of phosphonium salts followed by sp2-sp3 coupling of phosphorus ligands-an underdeveloped manifold for forming C-C bonds.
Collapse
Affiliation(s)
- Xuan Zhang
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
| | - Kyle G Nottingham
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
| | - Chirag Patel
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
| | | | - Jeffrey N Levy
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
| | - Robert S Paton
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA.
| | - Andrew McNally
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA.
| |
Collapse
|
10
|
Klare HFT, Albers L, Süsse L, Keess S, Müller T, Oestreich M. Silylium Ions: From Elusive Reactive Intermediates to Potent Catalysts. Chem Rev 2021; 121:5889-5985. [PMID: 33861564 DOI: 10.1021/acs.chemrev.0c00855] [Citation(s) in RCA: 107] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The history of silyl cations has all the makings of a drama but with a happy ending. Being considered reactive intermediates impossible to isolate in the condensed phase for decades, their actual characterization in solution and later in solid state did only fuel the discussion about their existence and initially created a lot of controversy. This perception has completely changed today, and silyl cations and their donor-stabilized congeners are now widely accepted compounds with promising use in synthetic chemistry. This review provides a comprehensive summary of the fundamental facts and principles of the chemistry of silyl cations, including reliable ways of their preparation as well as their physical and chemical properties. The striking features of silyl cations are their enormous electrophilicity and as such reactivity as super Lewis acids as well as fluorophilicity. Known applications rely on silyl cations as reactants, stoichiometric reagents, and promoters where the reaction success is based on their steady regeneration over the course of the reaction. Silyl cations can even be discrete catalysts, thereby opening the next chapter of their way into the toolbox of synthetic methodology.
Collapse
Affiliation(s)
- Hendrik F T Klare
- Institut für Chemie, Technische Universität Berlin, Strasse des 17 Juni 115, 10623 Berlin, Germany
| | - Lena Albers
- Institut für Chemie, Carl von Ossietzky Universität Oldenburg, Carl von Ossietzky-Strasse 9-11, 26129 Oldenburg, Germany
| | - Lars Süsse
- Institut für Chemie, Technische Universität Berlin, Strasse des 17 Juni 115, 10623 Berlin, Germany
| | - Sebastian Keess
- Institut für Chemie, Technische Universität Berlin, Strasse des 17 Juni 115, 10623 Berlin, Germany
| | - Thomas Müller
- Institut für Chemie, Carl von Ossietzky Universität Oldenburg, Carl von Ossietzky-Strasse 9-11, 26129 Oldenburg, Germany
| | - Martin Oestreich
- Institut für Chemie, Technische Universität Berlin, Strasse des 17 Juni 115, 10623 Berlin, Germany
| |
Collapse
|
11
|
Asok N, Gaffen JR, Pradhan E, Zeng T, Baumgartner T. Structure-reactivity studies on hypervalent square-pyramidal dithieno[3,2-b:2',3'-d]phospholes. Dalton Trans 2021; 50:2243-2252. [PMID: 33503083 DOI: 10.1039/d1dt00062d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of neutral pentacoordinate dithieno[3,2-b:2',3'-d]phosphole compounds were synthesized by [4 + 1] cycloaddition with o-quinones. Counter to the expected trigonal bipyramidal geometry, the luminescent hypervalent dithienophospholes exhibit square pyramidal geometry with inherently Lewis acidic phosphorus center that is stabilized via supramolecular π-stacking interactions in the solid state and in solution. Due to their Lewis-acid character, the compounds react with nucleophiles, suggesting their potential as mediator in organic transformations. The new species thus present an intriguing structural plaform for the design of neutral P(v) Lewis acids with useful reactivities.
Collapse
Affiliation(s)
- Nayanthara Asok
- Department of Chemistry, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada.
| | | | | | | | | |
Collapse
|
12
|
Belli RG, Pantazis DA, McDonald R, Rosenberg L. Reversible Silylium Transfer between P-H and Si-H Donors. Angew Chem Int Ed Engl 2021; 60:2379-2384. [PMID: 33031611 DOI: 10.1002/anie.202011372] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Indexed: 11/11/2022]
Abstract
The Mo=PR2 π* orbital in a Mo phosphenium complex acts as acceptor in a new PIII -based Lewis superacid. This Lewis acid (LA) participates in electrophilic Si-H abstraction from E3 SiH to give a Mo-bound secondary phosphine ligand, Mo-PR2 H. The resulting Et3 Si+ ion remains associated with the Mo complex, stabilized by η1 -P-H donation, yet undergoes rapid exchange with an η1 -Si-H adduct of free silane in solution. The equilibrium between these two adducts presents an opportunity to assess the role of this new LA in catalytic reactions of silanes: is the LA acting as a catalyst or as an initiator? Preliminary results suggest that a cycle including the Mo-bound phosphine-silylium adduct dominates in the catalytic hydrosilylation of acetophenone, relative to a putative cycle involving the silane-silylium adduct or "free" silylium.
Collapse
Affiliation(s)
- Roman G Belli
- Department of Chemistry, University of Victoria, P.O. Box 1700 STN CSC, Victoria, British Columbia, V8W 2Y2, Canada
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Robert McDonald
- X-ray Crystallography Laboratory, Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Lisa Rosenberg
- Department of Chemistry, University of Victoria, P.O. Box 1700 STN CSC, Victoria, British Columbia, V8W 2Y2, Canada
| |
Collapse
|
13
|
Belli RG, Pantazis DA, McDonald R, Rosenberg L. Reversible Silylium Transfer between P‐H and Si‐H Donors. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202011372] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Roman G. Belli
- Department of Chemistry University of Victoria P.O. Box 1700 STN CSC Victoria British Columbia V8W 2Y2 Canada
| | - Dimitrios A. Pantazis
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Robert McDonald
- X-ray Crystallography Laboratory Department of Chemistry University of Alberta Edmonton Alberta T6G 2G2 Canada
| | - Lisa Rosenberg
- Department of Chemistry University of Victoria P.O. Box 1700 STN CSC Victoria British Columbia V8W 2Y2 Canada
| |
Collapse
|
14
|
Hamza A, Sorochkina K, Kótai B, Chernichenko K, Berta D, Bolte M, Nieger M, Repo T, Pápai I. Origin of Stereoselectivity in FLP-Catalyzed Asymmetric Hydrogenation of Imines. ACS Catal 2020. [DOI: 10.1021/acscatal.0c04263] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrea Hamza
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2, H-1117 Budapest, Hungary
| | - Kristina Sorochkina
- Department of Chemistry, University of Helsinki, A. I. Virtasen aukio 1, 00014 Helsinki, Finland
| | - Bianka Kótai
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2, H-1117 Budapest, Hungary
| | - Konstantin Chernichenko
- Department of Chemistry, University of Helsinki, A. I. Virtasen aukio 1, 00014 Helsinki, Finland
| | - Dénes Berta
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2, H-1117 Budapest, Hungary
| | - Michael Bolte
- Institute of Inorganic Chemistry, Goethe-University, Max-von-Laue-Strasse 7, D-60438 Frankfurt am Main, Germany
| | - Martin Nieger
- Department of Chemistry, University of Helsinki, A. I. Virtasen aukio 1, 00014 Helsinki, Finland
| | - Timo Repo
- Department of Chemistry, University of Helsinki, A. I. Virtasen aukio 1, 00014 Helsinki, Finland
| | - Imre Pápai
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2, H-1117 Budapest, Hungary
| |
Collapse
|
15
|
Muzalevskiy VM, Belyaeva KV, Trofimov BA, Nenajdenko VG. Organometal-Free Arylation and Arylation/Trifluoroacetylation of Quinolines by Their Reaction with CF 3-ynones and Base-Induced Rearrangement. J Org Chem 2020; 85:9993-10006. [PMID: 32631065 DOI: 10.1021/acs.joc.0c01277] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reaction of quinolines with CF3-ynones resulted in the formation of 1,3-oxazinoquinolines. Subsequent treatment of the reaction mixture with a base initiated deep structural transformation of primary products. Both steps proceed in very high yield. As a result, unusual rearrangement of 1,3-oxazinoquinolines to form either 2-arylquinolines or 2-aryl-3-trifluoroacetylquinolines was discovered. The decisive role of the base in the reaction direction was shown. Using these reactions, highly efficient pathways to 2-arylquinolines and 2-aryl-3-trifluoroacetylquinolines were elaborated to provide the corresponding compounds in high yields using a simple one-pot procedure. The possible mechanism of rearrangement is discussed.
Collapse
Affiliation(s)
- Vasiliy M Muzalevskiy
- Department of Chemistry, M. V. Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991 Russia
| | - Kseniya V Belyaeva
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, 1 Favorsky Street, Irkutsk 664033, Russia
| | - Boris A Trofimov
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, 1 Favorsky Street, Irkutsk 664033, Russia
| | - Valentine G Nenajdenko
- Department of Chemistry, M. V. Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991 Russia
| |
Collapse
|
16
|
Sapsford JS, Csókás D, Scott DJ, Turnell-Ritson RC, Piascik AD, Pápai I, Ashley AE. Establishing the Role of Triflate Anions in H 2 Activation by a Cationic Triorganotin(IV) Lewis Acid. ACS Catal 2020; 10:7573-7583. [PMID: 32905389 PMCID: PMC7469243 DOI: 10.1021/acscatal.0c02023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/05/2020] [Indexed: 12/13/2022]
Abstract
![]()
Cationic
Lewis acids (LAs) are gaining interest as targets for
frustrated Lewis pair (FLP)-mediated catalysis. Unlike neutral boranes,
which are the most prevalent LAs for FLP hydrogenations, the Lewis
acidity of cations can be tuned through modulation of the counteranion;
however, detailed studies on such anion effects are currently lacking
in the literature. Herein, we present experimental and computational
studies which probe the mechanism of H2 activation using iPr3SnOTf (1-OTf) in conjunction
with a coordinating (quinuclidine; qui) and noncoordinating (2,4,6-collidine;
col) base and compare its reactivity with {iPr3Sn·base}{Al[OC(CF3)3]4} (base = qui/col) systems which lack a coordinating anion to investigate
the active species responsible for H2 activation and hence
resolve any mechanistic roles for OTf– in the iPr3SnOTf-mediated pathway.
Collapse
Affiliation(s)
- Joshua S. Sapsford
- Molecular Sciences Research Hub, Imperial College, White City Campus, 80 Wood Lane, London W12 0BZ, U.K
| | - Dániel Csókás
- Institute of Organic Chemistry, Research Center for Natural Sciences, Magyar tudósok körútja 2, Budapest H-1117, Hungary
| | - Daniel J. Scott
- Institute of Inorganic Chemistry, University of Regensburg, Universitätsstraße 31, Regensburg 93051, Germany
| | - Roland C. Turnell-Ritson
- Molecular Sciences Research Hub, Imperial College, White City Campus, 80 Wood Lane, London W12 0BZ, U.K
| | - Adam D. Piascik
- Molecular Sciences Research Hub, Imperial College, White City Campus, 80 Wood Lane, London W12 0BZ, U.K
| | - Imre Pápai
- Institute of Organic Chemistry, Research Center for Natural Sciences, Magyar tudósok körútja 2, Budapest H-1117, Hungary
| | - Andrew E. Ashley
- Molecular Sciences Research Hub, Imperial College, White City Campus, 80 Wood Lane, London W12 0BZ, U.K
| |
Collapse
|
17
|
Mehta M, Goicoechea JM. Nitrenium Salts in Lewis Acid Catalysis. Angew Chem Int Ed Engl 2020; 59:2715-2719. [DOI: 10.1002/anie.201915547] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Indexed: 12/26/2022]
Affiliation(s)
- Meera Mehta
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Mansfield Rd. Oxford OX1 3TA UK
| | - Jose M. Goicoechea
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Mansfield Rd. Oxford OX1 3TA UK
| |
Collapse
|
18
|
Schorpp M, Krossing I. Soft interactions with hard Lewis acids: generation of mono- and dicationic alkaline-earth metal arene-complexes by direct oxidation. Chem Sci 2020; 11:2068-2076. [PMID: 32180929 PMCID: PMC7057851 DOI: 10.1039/c9sc06254h] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/12/2020] [Indexed: 12/26/2022] Open
Abstract
The synthesis of the first unsupported dicationic arene complexes of calcium and strontium [(η6-HMB)AE(oDFB)4]2+ is reported (HMB = hexamethylbenzene; AE = alkaline earth metal; oDFB = ortho-difluorobenzene). They were prepared by direct oxidation of the elemental metals employing the ligand-forming radical cation salt [HMB][WCA] as an oxidant (WCA = [Al(ORF)4] or [μF-{Al(ORF)3}2]; RF = C(CF3)3). In addition, monocationic η6-HMB complexes of calcium, strontium and barium supported by coordination of the monodentate anion [F-Al(ORF)3]- are reported. In all examples, almost undistorted η6-HMB coordination is observed with rather short M-arenecentroid distances approaching those observed with the isoelectronic but negatively charged pentamethylcyclopentadienyl ligand. The structure and bonding, thermodynamic stability and Lewis acidity (fluoride/hydride ion affinities, FIA/HIA) of the generated complexes were assessed by DFT methods. It followed that the gaseous dications [(η6-HMB)AE(oDFB)4]2+ are extremely hard Lewis acids that retain FIAs close to superacidity in solution.
Collapse
Affiliation(s)
- Marcel Schorpp
- Institut für Anorganische und Analytische Chemie , Freiburger Materialforschungszentrum (FMF) , Universität Freiburg , Albertstr. 21 , 79104 Freiburg , Germany .
| | - Ingo Krossing
- Institut für Anorganische und Analytische Chemie , Freiburger Materialforschungszentrum (FMF) , Universität Freiburg , Albertstr. 21 , 79104 Freiburg , Germany .
| |
Collapse
|
19
|
Affiliation(s)
- Meera Mehta
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Mansfield Rd. Oxford OX1 3TA UK
| | - Jose M. Goicoechea
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Mansfield Rd. Oxford OX1 3TA UK
| |
Collapse
|
20
|
Chan YC, Yeung YY. Halogen-Bond-Catalyzed Addition of Carbon-Based Nucleophiles to N-Acylimminium Ions. Org Lett 2019; 21:5665-5669. [DOI: 10.1021/acs.orglett.9b02006] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yuk-Cheung Chan
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China
| | - Ying-Yeung Yeung
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China
| |
Collapse
|
21
|
Gilhula JC, Radosevich AT. Tetragonal phosphorus(v) cations as tunable and robust catalytic Lewis acids. Chem Sci 2019; 10:7177-7182. [PMID: 31588285 PMCID: PMC6685354 DOI: 10.1039/c9sc02463h] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 06/17/2019] [Indexed: 01/19/2023] Open
Abstract
The synthesis and catalytic reactivity of a class of water-tolerant cationic phosphorus-based Lewis acids is reported.
The synthesis and catalytic reactivity of a class of water-tolerant cationic phosphorus-based Lewis acids is reported. Corrole-based phosphorus(v) cations of the type [ArP(cor)][B(C6F5)4] (Ar = C6H5, 3,5-(CF3)2C6H3; cor = 5,10,15-(C6H5)3corrolato3–, 5,10,15-(C6F5)3corrolato3–) were synthesized and characterized by NMR and X-ray diffraction. The visible electronic absorption spectra of these cationic phosphacorroles depend strongly on the coordination environment at phosphorus, and their Lewis acidities are quantified by spectrophotometric titrations. DFT analyses establish that the character of the P-acceptor orbital comprises P–N antibonding interactions in the basal plane of the phosphacorrole. Consequently, the cationic phosphacorroles display unprecedented stability to water and alcohols while remaining highly active and robust Lewis acid catalysts for carbonyl hydrosilylation, Csp3–H bond functionalization, and carbohydrate deoxygenation reactions.
Collapse
Affiliation(s)
- James C Gilhula
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
| | - Alexander T Radosevich
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA .
| |
Collapse
|
22
|
Daru J, Bakó I, Stirling A, Pápai I. Mechanism of Heterolytic Hydrogen Splitting by Frustrated Lewis Pairs: Comparison of Static and Dynamic Models. ACS Catal 2019. [DOI: 10.1021/acscatal.9b01137] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- János Daru
- Research Center for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest H-1117, Hungary
| | - Imre Bakó
- Research Center for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest H-1117, Hungary
| | - András Stirling
- Research Center for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest H-1117, Hungary
| | - Imre Pápai
- Research Center for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest H-1117, Hungary
| |
Collapse
|
23
|
Bayne JM, Stephan DW. C−F Bond Activation Mediated by Phosphorus Compounds. Chemistry 2019; 25:9350-9357. [DOI: 10.1002/chem.201900542] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Julia M. Bayne
- Department of ChemistryUniversity of Toronto 80 St. George St. Toronto Ontario M5S 3H6 Canada
| | - Douglas W. Stephan
- Department of ChemistryUniversity of Toronto 80 St. George St. Toronto Ontario M5S 3H6 Canada
| |
Collapse
|
24
|
Andrews RJ, Chitnis SS, Stephan DW. Carbonyl and olefin hydrosilylation mediated by an air-stable phosphorus(iii) dication under mild conditions. Chem Commun (Camb) 2019; 55:5599-5602. [PMID: 31020971 DOI: 10.1039/c9cc02460c] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The readily-accessible, air-stable Lewis acid [(terpy)PPh][B(C6F5)4]21 is shown to mediate the hydrosilylation of aldehydes, ketones, and olefins. The utility and mechanism of these hydrosilylations are considered.
Collapse
Affiliation(s)
- Ryan J Andrews
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON M5S 3H6, Canada.
| | | | | |
Collapse
|
25
|
Stepen AJ, Bursch M, Grimme S, Stephan DW, Paradies J. Electrophilic Phosphonium Cation‐Mediated Phosphane Oxide Reduction Using Oxalyl Chloride and Hydrogen. Angew Chem Int Ed Engl 2018; 57:15253-15256. [DOI: 10.1002/anie.201809275] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Arne J. Stepen
- Department of ChemistryUniversity of Paderborn Warburger Strasse 100 33098 Paderborn Germany
- Department of ChemistryUniversity of Toronto 80 St. George St Toronto Ontario M5S3H6 Canada
| | - Markus Bursch
- Mulliken Center for Theoretical ChemistryUniversity of Bonn Beringstr. 4 53115 Bonn Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical ChemistryUniversity of Bonn Beringstr. 4 53115 Bonn Germany
| | - Douglas W. Stephan
- Department of ChemistryUniversity of Toronto 80 St. George St Toronto Ontario M5S3H6 Canada
| | - Jan Paradies
- Department of ChemistryUniversity of Paderborn Warburger Strasse 100 33098 Paderborn Germany
| |
Collapse
|
26
|
Bayne JM, Fasano V, Szkop KM, Ingleson MJ, Stephan DW. Phosphorous(v) Lewis acids: water/base tolerant P 3-trimethylated trications. Chem Commun (Camb) 2018; 54:12467-12470. [PMID: 30335095 DOI: 10.1039/c8cc06564k] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The water/base intolerance of the previously reported electrophilic phosphonium cations has been overcome by replacing the labile electron-withdrawing groups generally attached to phosphorus (e.g. -F, -OAr, -CF3) with methyl groups. Tri-phosphorus(v) tricationic species, accessible in one-pot from commercially available materials, are air and water/base tolerant, yet are sufficiently Lewis acidic for catalysis.
Collapse
Affiliation(s)
- J M Bayne
- Department of Chemistry, University of Toronto, M5S 3H6, Canada.
| | | | | | | | | |
Collapse
|
27
|
Greb L. Lewis Superacids: Classifications, Candidates, and Applications. Chemistry 2018; 24:17881-17896. [DOI: 10.1002/chem.201802698] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Lutz Greb
- Anorganisch-Chemisches InstitutUniversität Heidelberg Im Neuenheimer Feld 270 Germany
| |
Collapse
|
28
|
Stepen AJ, Bursch M, Grimme S, Stephan DW, Paradies J. Reduktion von Phosphanoxiden mit Oxalylchlorid und Wasserstoff, vermittelt durch ein elektrophiles Phosphoniumkation. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201809275] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Arne J. Stepen
- Department ChemieUniversität Paderborn Warburger Straße 100 33098 Paderborn Deutschland
- Department of ChemistryUniversity of Toronto 80 St. George St Toronto Ontario M5S3H6 Kanada
| | - Markus Bursch
- Mulliken Center for Theoretical ChemistryUniversität Bonn Beringstraße 4 53115 Bonn Deutschland
| | - Stefan Grimme
- Mulliken Center for Theoretical ChemistryUniversität Bonn Beringstraße 4 53115 Bonn Deutschland
| | - Douglas W. Stephan
- Department of ChemistryUniversity of Toronto 80 St. George St Toronto Ontario M5S3H6 Kanada
| | - Jan Paradies
- Department ChemieUniversität Paderborn Warburger Straße 100 33098 Paderborn Deutschland
| |
Collapse
|
29
|
LaFortune JHW, Szkop KM, Farinha FE, Johnstone TC, Postle S, Stephan DW. Probing steric influences on electrophilic phosphonium cations: a comparison of [(3,5-(CF3)2C6H3)3PF]+ and [(C6F5)3PF]+. Dalton Trans 2018; 47:11411-11419. [DOI: 10.1039/c8dt02594k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electrophilic phosphonium cation (EPC) salt [(3,5-(CF3)2C6H3)3PF][B(C6F5)4] (2) can display catalytic activity greater than its thermodynamic acidity would suggest. The role of steric factors is explored.
Collapse
Affiliation(s)
| | - Kevin M. Szkop
- Department of Chemistry
- University of Toronto
- Toronto
- Canada M5S 3H6
| | - Farah E. Farinha
- Department of Chemistry
- University of Toronto
- Toronto
- Canada M5S 3H6
| | | | - Shawn Postle
- Department of Chemistry
- University of Toronto
- Toronto
- Canada M5S 3H6
| | | |
Collapse
|