1
|
Tan CY, Kim M, Park I, Kim Y, Hong S. Site-Selective Pyridine C-H Alkylation with Alcohols and Thiols via Single-Electron Transfer of Frustrated Lewis Pairs. Angew Chem Int Ed Engl 2022; 61:e202213857. [PMID: 36314414 DOI: 10.1002/anie.202213857] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Indexed: 11/07/2022]
Abstract
A unified strategy for the deoxygenative or desulfurative pyridylation of various alcohols and thiols has been developed through a single-electron transfer (SET) process of frustrated Lewis pairs (FLPs) derived from pyridinium salts and PtBu3 . Mechanistic studies revealed that N-amidopyridinium salts serve as effective Lewis acids for the formation of FLPs with PtBu3 , and the generated phosphine radical cation ionically couples with the in situ generated xanthate, eventually affording the alkyl radical through facile β-scission under photocatalyst-free conditions. The reaction efficiency was further accelerated by visible-light irradiation. This method is conceptually appealing by using encounter complexes in FLP chemistry to promote SET, which provides a previously unrecognized opportunity for the selective heteroarylation of a diverse range of alcohols and thiols with various functional groups, even in complex settings under mild reaction conditions.
Collapse
Affiliation(s)
- Chang-Yin Tan
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
| | - Myojeong Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
| | - Inyoung Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
| | - Yuhyun Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
| | - Sungwoo Hong
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
| |
Collapse
|
2
|
Thorwart T, Hartmann D, Greb L. Dihydrogen Activation with a Neutral, Intermolecular Silicon(IV)-Amine Frustrated Lewis Pair. Chemistry 2022; 28:e202202273. [PMID: 35861023 DOI: 10.1002/chem.202202273] [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: 07/20/2022] [Indexed: 01/07/2023]
Abstract
The heterolytic cleavage of dihydrogen constitutes the hallmark reaction of frustrated Lewis pairs (FLP). While being well-established for planar Lewis acids, such as boranes or silylium ions, the observation of the primary H2 splitting products with non-planar Lewis acid FLPs remained elusive. In the present work, we report bis(perfluoro-N-phenyl-ortho-amidophenolato)silane and its application in dihydrogen activation to a fully characterized hydridosilicate. The strict design of the Lewis acid, the limited selection of the Lewis base, and the distinct reaction conditions emphasize the narrow tolerance to achieve this fascinating process with a tetrahedral Lewis acid.
Collapse
Affiliation(s)
- Thaddäus Thorwart
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Deborah Hartmann
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Lutz Greb
- Department of Chemistry and Biochemistry-Inorganic Chemistry, Freie Universität Berlin, Fabeckstr. 34/36, 14195, Berlin, Germany
| |
Collapse
|
3
|
Litle ED, Gabbaï FP. Metal→Carbon Dative Bonding. Angew Chem Int Ed Engl 2022; 61:e202201841. [DOI: 10.1002/anie.202201841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Elishua D. Litle
- Department of Chemistry Texas A&M University College Station TX 77843 USA
| | - François P. Gabbaï
- Department of Chemistry Texas A&M University College Station TX 77843 USA
| |
Collapse
|
4
|
Wu Y, Zhao Z, Chen T, Tan J, Qu Z, Grimme S, Zhao Y, Stephan DW. The Varied Frustrated Lewis Pair Reactivity of the Germylene Phosphaketene (CH{(CMe)(2,6- i Pr 2 C 6 H 3 N)} 2 )GePCO. Chemistry 2022; 28:e202200666. [PMID: 35262970 PMCID: PMC9314608 DOI: 10.1002/chem.202200666] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Indexed: 01/08/2023]
Abstract
The germylene species (CH{(CMe)(2,6-iPr2 C6 H3 N)}2 )GePCO 1 is shown to react with the Lewis acids (E(C6 F5 )3 E=B, Al). Nonetheless, 1 participates in FLP chemistry with electron deficient alkynes or olefins, acting as an intramolecular FLP. In contrast, in the presence of B(C6 F5 )3 and an electron rich alkyne, 1 behaves as Ge-based nucleophile to effect intermolecular FLP addition to the alkyne. This reactivity demonstrates that the reaction pathway is controlled by the nature of the electrophile and nucleophile generated in solution, as revealed by extensive DFT calculations.
Collapse
Affiliation(s)
- Yile Wu
- Institute of Drug Discovery TechnologyNingbo UniversityNingbo315211ZhejiangP. R. China
- State Key Laboratory of Elemento-Organic ChemistryNankai University30071TianjinP. R. China
| | - Zhao Zhao
- Institute of Drug Discovery TechnologyNingbo UniversityNingbo315211ZhejiangP. R. China
| | - Ting Chen
- Institute of Drug Discovery TechnologyNingbo UniversityNingbo315211ZhejiangP. R. China
| | - Jingjie Tan
- Institute of Drug Discovery TechnologyNingbo UniversityNingbo315211ZhejiangP. R. China
| | - Zheng‐Wang Qu
- Mulliken Center for Theoretical ChemistryUniversity of BonnBeringstr. 453115BonnGermany
| | - Stefan Grimme
- Mulliken Center for Theoretical ChemistryUniversity of BonnBeringstr. 453115BonnGermany
| | - Yufen Zhao
- Institute of Drug Discovery TechnologyNingbo UniversityNingbo315211ZhejiangP. R. China
- Department of ChemistryXiamen UniversityXiamen361005FujianP. R. China
| | - Douglas W. Stephan
- Institute of Drug Discovery TechnologyNingbo UniversityNingbo315211ZhejiangP. R. China
- Department of ChemistryUniversity of Toronto80 St. George StTorontoONM5S3H6Canada
| |
Collapse
|
5
|
Litle ED, Gabbaï FP. Metal→Carbon Dative Bonding. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202201841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Elishua D. Litle
- Department of Chemistry Texas A&M University College Station TX 77843 USA
| | - François P. Gabbaï
- Department of Chemistry Texas A&M University College Station TX 77843 USA
| |
Collapse
|
6
|
Activation of Small Molecules and Hydrogenation of CO2 Catalyzed by Frustrated Lewis Pairs. Catalysts 2022. [DOI: 10.3390/catal12020201] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The chemistry of frustrated Lewis pair (FLP) is widely explored in the activation of small molecules, the hydrogenation of CO2, and unsaturated organic species. A survey of several experimental works on the activation of small molecules by FLPs and the related mechanistic insights into their reactivity from electronic structure theory calculation are provided in the present review, along with the catalytic hydrogenation of CO2. The mechanistic insight into H2 activation is thoroughly discussed, which may provide a guideline to design more efficient FLP for H2 activation. FLPs can activate other small molecules like, CO, NO, CO2, SO2, N2O, alkenes, alkynes, etc. by cooperative action of the Lewis centers of FLPs, as revealed by several computational analyses. The activation barrier of H2 and other small molecules by the FLP can be decreased by utilizing the aromaticity criterion in the FLP as demonstrated by the nucleus independent chemical shift (NICS) analysis. The term boron-ligand cooperation (BLC), which is analogous to the metal-ligand cooperation (MLC), is invoked to describe a distinct class of reactivity of some specific FLPs towards H2 activation.
Collapse
|
7
|
Burton KI, Elser I, Waked AE, Wagener T, Andrews RJ, Glorius F, Stephan DW. Bipyridinium and Phenanthrolinium Dications for Metal-Free Hydrodefluorination: Distinctive Carbon-Based Reactivity. Chemistry 2021; 27:11730-11737. [PMID: 34107119 DOI: 10.1002/chem.202101534] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Indexed: 01/06/2023]
Abstract
The development of novel Lewis acids derived from bipyridinium and phenanthrolinium dications is reported. Calculations of Hydride Ion Affinity (HIA) values indicate high carbon-based Lewis acidity at the ortho and para positions. This arises in part from extensive LUMO delocalization across the aromatic backbones. Species [C10 H6 R2 N2 CH2 CH2 ]2+ (R=H [1 a]2+ , Me [1 f]2+ , tBu [1 g]2+ ), and [C12 H4 R4 N2 CH2 CH2 ]2+ (R=H [2 a]2+ , Me [2 b]2+ ) were prepared and evaluated for use in the initiation of hydrodefluorination (HDF) catalysis. Compound [2 a]2+ proved highly effective towards generating catalytically active silylium cations via Lewis acid-mediated hydride abstraction from silane. This enabled the HDF of a range of aryl- and alkyl- substituted sp3 (C-F) bonds under mild conditions. The protocol was also adapted to effect the deuterodefluorination of cis-2,4,6-(CF3 )3 C6 H9 . The dications are shown to act as hydride acceptors with the isolation of neutral species C16 H14 N2 (3 a) and C16 H10 Me4 N2 (3 b) and monocationic species [C14 H13 N2 ]+ ([4 a]+ ) and [C18 H21 N2 ]+ ([4 b]+ ). Experimental and computational data provide further support that the dications are initiators in the generation of silylium cations.
Collapse
Affiliation(s)
- Katherine I Burton
- Department of Chemistry, Davenport Research Laboratories, University of Toronto, Toronto, Ontario, M5S 3H6, Canada
| | - Iris Elser
- Department of Chemistry, Davenport Research Laboratories, University of Toronto, Toronto, Ontario, M5S 3H6, Canada
| | - Alexander E Waked
- Department of Chemistry, Davenport Research Laboratories, University of Toronto, Toronto, Ontario, M5S 3H6, Canada
| | - Tobias Wagener
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Correnstraβe 40, 48149, Münster, Germany
| | - Ryan J Andrews
- Department of Chemistry, Davenport Research Laboratories, University of Toronto, Toronto, Ontario, M5S 3H6, Canada
| | - Frank Glorius
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Correnstraβe 40, 48149, Münster, Germany
| | - Douglas W Stephan
- Department of Chemistry, Davenport Research Laboratories, University of Toronto, Toronto, Ontario, M5S 3H6, Canada
| |
Collapse
|
8
|
Liu WC, Kim Y, Gabbaï FP. Conformational Switching through the One-Electron Reduction of an Acridinium-based, γ-Cationic Phosphine Gold Complex. Chemistry 2021; 27:6701-6705. [PMID: 33528859 DOI: 10.1002/chem.202100389] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Indexed: 11/07/2022]
Abstract
Our efforts in the chemistry of gold complexes featuring ambiphilic phosphine-carbenium L/Z-type ligand have led us to consider the reduction of the carbenium moiety as a means to modulate the gold-carbenium interaction present in these complexes. Here, it was shown that the one-electron reduction of [(o-Ph2 P(C6 H4 )Acr)AuCl]+ (Acr=9-N-methylacridinium) produces a neutral stable radical, the structure of which showed a marked increase in the Au-Acr distance. Related structural changes were observed for the phosphine oxide analogue [(o-Ph2 P(O)(C6 H4 )Acr]+ , the reduction of which interfered with the P=O→carbenium interaction. These structural effects, driven by a reduction-induced change in the electronic and electrostatic characteristics of the compounds, showed that the charge and accepting properties of the carbenium unit can be modulated. These results highlight the redox-noninnocence of carbenium Z-type ligand, a feature that can be exploited to induce specific conformational changes.
Collapse
Affiliation(s)
- Wei-Chun Liu
- Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA
| | - Youngmin Kim
- Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA
| | - François P Gabbaï
- Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA
| |
Collapse
|
9
|
Simon M, Radius M, Wagner HE, Breher F. Imidazolyl Alanes – Synthesis, Structures, and Reactivity Studies. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Martin Simon
- Institute of Inorganic Chemistry Division Molecular Chemistry Karlsruhe Institute of Technology (KIT) Engesserstr.15 76131 Karlsruhe Germany
| | - Michael Radius
- Institute of Inorganic Chemistry Division Molecular Chemistry Karlsruhe Institute of Technology (KIT) Engesserstr.15 76131 Karlsruhe Germany
| | - Hanna E. Wagner
- Institute of Inorganic Chemistry Division Molecular Chemistry Karlsruhe Institute of Technology (KIT) Engesserstr.15 76131 Karlsruhe Germany
| | - Frank Breher
- Institute of Inorganic Chemistry Division Molecular Chemistry Karlsruhe Institute of Technology (KIT) Engesserstr.15 76131 Karlsruhe Germany
| |
Collapse
|
10
|
Kinder TA, Pior R, Blomeyer S, Neumann B, Stammler H, Mitzel NW. A Neutral Germanium/Phosphorus Frustrated Lewis Pair and Its Contrasting Reactivity Compared to Its Silicon Analogue. Chemistry 2019; 25:5899-5903. [PMID: 30843630 DOI: 10.1002/chem.201901068] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Indexed: 11/06/2022]
Affiliation(s)
- Timo A. Kinder
- Lehrstuhl für Anorganische Chemie und Strukturchemie und Centrum für, Molekulare Materialien CM2Universität Bielefeld Universitätsstraße 25 33615 Bielefeld Germany
| | - René Pior
- Lehrstuhl für Anorganische Chemie und Strukturchemie und Centrum für, Molekulare Materialien CM2Universität Bielefeld Universitätsstraße 25 33615 Bielefeld Germany
| | - Sebastian Blomeyer
- Lehrstuhl für Anorganische Chemie und Strukturchemie und Centrum für, Molekulare Materialien CM2Universität Bielefeld Universitätsstraße 25 33615 Bielefeld Germany
| | - Beate Neumann
- Lehrstuhl für Anorganische Chemie und Strukturchemie und Centrum für, Molekulare Materialien CM2Universität Bielefeld Universitätsstraße 25 33615 Bielefeld Germany
| | - Hans‐Georg Stammler
- Lehrstuhl für Anorganische Chemie und Strukturchemie und Centrum für, Molekulare Materialien CM2Universität Bielefeld Universitätsstraße 25 33615 Bielefeld Germany
| | - Norbert W. Mitzel
- Lehrstuhl für Anorganische Chemie und Strukturchemie und Centrum für, Molekulare Materialien CM2Universität Bielefeld Universitätsstraße 25 33615 Bielefeld Germany
| |
Collapse
|
11
|
Elliott DC, Marti A, Mauleón P, Pfaltz A. H
2
Activation by Non‐Transition‐Metal Systems: Hydrogenation of Aldimines and Ketimines with LiN(SiMe
3
)
2. Chemistry 2019; 25:1918-1922. [DOI: 10.1002/chem.201805549] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Daniel C. Elliott
- Department of ChemistryUniversity of Basel St. Johanns-Ring 19 4056 Basel Switzerland
| | - Alex Marti
- Department of ChemistryUniversity of Basel St. Johanns-Ring 19 4056 Basel Switzerland
| | - Pablo Mauleón
- Department of Organic ChemistryUniversidad Autónoma de Madrid c/ Fco. Tomás y Valiente 7, Cantoblanco 28049 Madrid Spain
| | - Andreas Pfaltz
- Department of ChemistryUniversity of Basel St. Johanns-Ring 19 4056 Basel Switzerland
| |
Collapse
|
12
|
Zhao T, Hu X, Wu Y, Zhang Z. Hydrogenation of CO2
to Formate with H2
: Transition Metal Free Catalyst Based on a Lewis Pair. Angew Chem Int Ed Engl 2018; 58:722-726. [DOI: 10.1002/anie.201809634] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 11/04/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Tianxiang Zhao
- Separation Engineering Research Center; School of Chemistry and Chemical Engineering; Nanjing University; Nanjing 210093 P. R. China
| | - Xingbang Hu
- Separation Engineering Research Center; School of Chemistry and Chemical Engineering; Nanjing University; Nanjing 210093 P. R. China
| | - Youting Wu
- Separation Engineering Research Center; School of Chemistry and Chemical Engineering; Nanjing University; Nanjing 210093 P. R. China
| | - Zhibing Zhang
- Separation Engineering Research Center; School of Chemistry and Chemical Engineering; Nanjing University; Nanjing 210093 P. R. China
| |
Collapse
|
13
|
Zhao T, Hu X, Wu Y, Zhang Z. Hydrogenation of CO2
to Formate with H2
: Transition Metal Free Catalyst Based on a Lewis Pair. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201809634] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Tianxiang Zhao
- Separation Engineering Research Center; School of Chemistry and Chemical Engineering; Nanjing University; Nanjing 210093 P. R. China
| | - Xingbang Hu
- Separation Engineering Research Center; School of Chemistry and Chemical Engineering; Nanjing University; Nanjing 210093 P. R. China
| | - Youting Wu
- Separation Engineering Research Center; School of Chemistry and Chemical Engineering; Nanjing University; Nanjing 210093 P. R. China
| | - Zhibing Zhang
- Separation Engineering Research Center; School of Chemistry and Chemical Engineering; Nanjing University; Nanjing 210093 P. R. China
| |
Collapse
|
14
|
Affiliation(s)
- Jan Paradies
- Department of Chemistry; University of Paderborn; Warburger Strasse 100 33098 Paderborn Germany
| |
Collapse
|
15
|
Fasano V, Curless LD, Radcliffe JE, Ingleson MJ. Frustrated Lewis Pair Mediated 1,2-Hydrocarbation of Alkynes. Angew Chem Int Ed Engl 2017; 56:9202-9206. [PMID: 28608991 PMCID: PMC5577509 DOI: 10.1002/anie.201705100] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Indexed: 01/26/2023]
Abstract
Frustrated Lewis pair (FLP) chemistry enables a rare example of alkyne 1,2-hydrocarbation with N-methylacridinium salts as the carbon Lewis acid. This 1,2-hydrocarbation process does not proceed through a concerted mechanism as in alkyne syn-hydroboration, or through an intramolecular 1,3-hydride migration as operates in the only other reported alkyne 1,2-hydrocarbation reaction. Instead, in this study, alkyne 1,2-hydrocarbation proceeds by a novel mechanism involving alkyne dehydrocarbation with a carbon Lewis acid based FLP to form the new C-C bond. Subsequently, intermolecular hydride transfer occurs, with the Lewis acid component of the FLP acting as a hydride shuttle that enables alkyne 1,2-hydrocarbation.
Collapse
Affiliation(s)
- Valerio Fasano
- School of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
| | - Liam D. Curless
- School of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
| | - James E. Radcliffe
- School of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
| | | |
Collapse
|
16
|
Fasano V, Curless LD, Radcliffe JE, Ingleson MJ. Frustrated Lewis Pair Mediated 1,2-Hydrocarbation of Alkynes. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201705100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Valerio Fasano
- School of Chemistry; University of Manchester; Oxford Road Manchester M13 9PL UK
| | - Liam D. Curless
- School of Chemistry; University of Manchester; Oxford Road Manchester M13 9PL UK
| | - James E. Radcliffe
- School of Chemistry; University of Manchester; Oxford Road Manchester M13 9PL UK
| | - Michael J. Ingleson
- School of Chemistry; University of Manchester; Oxford Road Manchester M13 9PL UK
| |
Collapse
|
17
|
Follet E, Mayer P, Stephenson DS, Ofial AR, Berionni G. Reactivity-Tuning in Frustrated Lewis Pairs: Nucleophilicity and Lewis Basicity of Sterically Hindered Phosphines. Chemistry 2017; 23:7422-7427. [DOI: 10.1002/chem.201701080] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Indexed: 01/21/2023]
Affiliation(s)
- Elsa Follet
- Department Chemie; Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 München Germany
| | - Peter Mayer
- Department Chemie; Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 München Germany
| | - David S. Stephenson
- Department Chemie; Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 München Germany
| | - Armin R. Ofial
- Department Chemie; Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 München Germany
| | - Guillaume Berionni
- Department Chemie; Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 München Germany
| |
Collapse
|
18
|
Fasano V, Ingleson MJ. Expanding Water/Base Tolerant Frustrated Lewis Pair Chemistry to Alkylamines Enables Broad Scope Reductive Aminations. Chemistry 2017; 23:2217-2224. [PMID: 27977048 PMCID: PMC5396349 DOI: 10.1002/chem.201605466] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Indexed: 01/05/2023]
Abstract
Lower Lewis acidity boranes demonstrate greater tolerance to combinations of water/strong Brønsted bases than B(C6 F5 )3 , this enables Si-H bond activation by a frustrated Lewis pair (FLP) mechanism to proceed in the presence of H2 O/alkylamines. Specifically, BPh3 has improved water tolerance in the presence of alkylamines as the Brønsted acidic adduct H2 O-BPh3 does not undergo irreversible deprotonation with aliphatic amines in contrast to H2 O-B(C6 F5 )3 . Therefore BPh3 is a catalyst for the reductive amination of aldehydes and ketones with alkylamines using silanes as reductants. A range of amines inaccessible using B(C6 F5 )3 as catalyst, were accessible by reductive amination catalysed by BPh3 via an operationally simple methodology requiring no purification of BPh3 or reagents/solvent. BPh3 has a complementary reductive amination scope to B(C6 F5 )3 with the former not an effective catalyst for the reductive amination of arylamines, while the latter is not an effective catalyst for the reductive amination of alkylamines. This disparity is due to the different pKa values of the water-borane adducts and the greater susceptibility of BPh3 species towards protodeboronation. An understanding of the deactivation processes occurring using B(C6 F5 )3 and BPh3 as reductive amination catalysts led to the identification of a third triarylborane, B(3,5-Cl2 C6 H3 )3 , that has a broader substrate scope being able to catalyse the reductive amination of both aryl and alkyl amines with carbonyls.
Collapse
Affiliation(s)
- Valerio Fasano
- School of ChemistryUniversity of ManchesterManchesterM13 9PLUK
| | | |
Collapse
|
19
|
Fasano V, Radcliffe JE, Curless LD, Ingleson MJ. N-Methyl-Benzothiazolium Salts as Carbon Lewis Acids for Si-H σ-Bond Activation and Catalytic (De)hydrosilylation. Chemistry 2017; 23:187-193. [PMID: 27780294 PMCID: PMC5396135 DOI: 10.1002/chem.201604613] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Indexed: 11/08/2022]
Abstract
N-Me-Benzothiazolium salts are introduced as a new family of Lewis acids able to activate Si-H σ bonds. These carbon-centred Lewis acids were demonstrated to have comparable Lewis acidity towards hydride as found for the triarylboranes widely used in Si-H σ-bond activation. However, they display low Lewis acidity towards hard Lewis bases such as Et3 PO and H2 O in contrast to triarylboranes. The N-Me-benzothiazolium salts are effective catalysts for a range of hydrosilylation and dehydrosilylation reactions. Judicious selection of the C2 aryl substituent in these cations enables tuning of the steric and electronic environment around the electrophilic centre to generate more active catalysts. Finally, related benzoxazolium and benzimidazolium salts were found also to be active for Si-H bond activation and as catalysts for the hydrosilylation of imines.
Collapse
Affiliation(s)
- Valerio Fasano
- School of ChemistryUniversity of ManchesterManchesterM13 9PLUK
| | | | - Liam D. Curless
- School of ChemistryUniversity of ManchesterManchesterM13 9PLUK
| | | |
Collapse
|
20
|
Maier AFG, Tussing S, Schneider T, Flörke U, Qu ZW, Grimme S, Paradies J. Dehydrierende Oxidation von Indolinen und anderen Heterocyclen durch frustrierte Lewis-Paare. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201606426] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Alexander F. G. Maier
- Institut für Organische Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Deutschland
| | - Sebastian Tussing
- Institut für Organische Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Deutschland
| | - Tobias Schneider
- Institut für Organische Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Deutschland
| | - Ulrich Flörke
- Institut für Anorganische 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
| | - 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
|
21
|
Maier AFG, Tussing S, Schneider T, Flörke U, Qu ZW, Grimme S, Paradies J. Frustrated Lewis Pair Catalyzed Dehydrogenative Oxidation of Indolines and Other Heterocycles. Angew Chem Int Ed Engl 2016; 55:12219-23. [PMID: 27594431 DOI: 10.1002/anie.201606426] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 08/02/2016] [Indexed: 11/11/2022]
Abstract
An acceptorless dehydrogenation of heterocycles catalyzed by frustrated Lewis pairs (FLPs) was developed. Oxidation with concomitant liberation of molecular hydrogen proceeded in high to excellent yields for N-protected indolines as well as four other substrate classes. The mechanism of this unprecedented FLP-catalyzed reaction was investigated by mechanistic studies, characterization of reaction intermediates by NMR spectroscopy and X-ray crystal analysis, and by quantum-mechanical calculations. Hydrogen liberation from the ammonium hydridoborate intermediate is the rate-determining step of the oxidation. The addition of a weaker Lewis acid as a hydride shuttle increased the reaction rate by a factor of 2.28 through a second catalytic cycle.
Collapse
Affiliation(s)
- Alexander F G Maier
- Institute of Organic Chemistry, University of Paderborn, Warburger Strasse 100, 33098, Paderborn, Germany
| | - Sebastian Tussing
- Institute of Organic Chemistry, University of Paderborn, Warburger Strasse 100, 33098, Paderborn, Germany
| | - Tobias Schneider
- Institute of Organic Chemistry, University of Paderborn, Warburger Strasse 100, 33098, Paderborn, Germany
| | - Ulrich Flörke
- Institute of Inorganic 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
| | - 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
|
22
|
Litters S, Kaifer E, Himmel HJ. A Radical Tricationic Rhomboid Tetraborane(4) with Four-Center, Five-Electron Bonding. Angew Chem Int Ed Engl 2016; 55:4345-7. [PMID: 26924813 DOI: 10.1002/anie.201600296] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 01/26/2016] [Indexed: 11/07/2022]
Abstract
The red-colored tetraborane(4) [B4 (hpp)4 ](3+.) (3; hpp=1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinate) with a rhomboid B4 skeleton stabilized by four N donors, was synthesized by the reaction of the strong hydride abstraction reagent [(acridine)BCl2 ][AlCl4 ] with the electron-rich diborane(4) [HB(hpp)]2 (1). The salt 3[AlCl4 ]3 was structurally characterized and the presence of unpaired electrons proven by EPR measurements. The unprecedented radical tricationic 3 is distinguished by a high positive charge and boron atoms in a low oxidation state (less than two).
Collapse
Affiliation(s)
- Sebastian Litters
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Hans-Jörg Himmel
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.
| |
Collapse
|
23
|
Litters S, Kaifer E, Himmel HJ. Ein radikaltrikationisches Tetraboran(4) mit rhombischer Struktur und Vier-Zentren-fünf-Elektronen-Bindung. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201600296] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sebastian Litters
- Anorganisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - Elisabeth Kaifer
- Anorganisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - Hans-Jörg Himmel
- Anorganisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| |
Collapse
|
24
|
Vom Stein T, Peréz M, Dobrovetsky R, Winkelhaus D, Caputo CB, Stephan DW. Electrophilic Fluorophosphonium Cations in Frustrated Lewis Pair Hydrogen Activation and Catalytic Hydrogenation of Olefins. Angew Chem Int Ed Engl 2015; 54:10178-82. [PMID: 26178268 DOI: 10.1002/anie.201504109] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/13/2015] [Indexed: 12/19/2022]
Abstract
The combination of phosphorus(V)-based Lewis acids with diaryl amines and diaryl silylamines promotes reversible activation of dihydrogen and can be further exploited in metal-free catalytic olefin hydrogenation. Combined experimental and density functional theory (DFT) studies suggest a frustrated Lewis pair type activation mechanism.
Collapse
Affiliation(s)
- Thorsten Vom Stein
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto Ontario M5S3H6 (Canada)
| | - Manuel Peréz
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto Ontario M5S3H6 (Canada)
| | - Roman Dobrovetsky
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto Ontario M5S3H6 (Canada)
| | - Daniel Winkelhaus
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto Ontario M5S3H6 (Canada)
| | - Christopher B Caputo
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto Ontario M5S3H6 (Canada)
| | - Douglas W Stephan
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto Ontario M5S3H6 (Canada).
| |
Collapse
|
25
|
vom Stein T, Peréz M, Dobrovetsky R, Winkelhaus D, Caputo CB, Stephan DW. Electrophilic Fluorophosphonium Cations in Frustrated Lewis Pair Hydrogen Activation and Catalytic Hydrogenation of Olefins. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201504109] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
26
|
Auth J, Padevet J, Mauleón P, Pfaltz A. Pyridylidene-Mediated Dihydrogen Activation Coupled with Catalytic Imine Reduction. Angew Chem Int Ed Engl 2015; 54:9542-5. [PMID: 26119973 DOI: 10.1002/anie.201503233] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 06/01/2015] [Indexed: 11/06/2022]
Abstract
In recent years, dihydrogen activation at non-metallic centers has received increasing attention. A system in which dihydrogen is trapped by a pyridylidene intermediate that is generated from a pyridinium salt and a base is now reported. The dihydropyridine formed in this process can act as reducing agent towards organic electrophiles. By coupling the hydrogen-activation step with subsequent hydride transfer from the dihydropyridine to an imine, a catalytic process was established. Treatment of the N-phenylimine of phenyl trifluoromethyl ketone with 5-20 mol% of N-mesityl-3,5-bis(2,6-dimethylphenyl)pyridinium triflate and 0.3-1.0 equivalents of LiN(SiMe3)2 under 50 bar of hydrogen gas resulted in high conversion into the corresponding amine.
Collapse
Affiliation(s)
- Johanna Auth
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel (Switzerland)
| | - Jaroslav Padevet
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel (Switzerland)
| | - Pablo Mauleón
- Department of Organic Chemistry, Universidad Autónoma de Madrid c/Fco. Tomás y Valiente 7, Cantoblanco 28049, Madrid (Spain).
| | - Andreas Pfaltz
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel (Switzerland).
| |
Collapse
|
27
|
Auth J, Padevet J, Mauleón P, Pfaltz A. Pyridylidene-Mediated Dihydrogen Activation Coupled with Catalytic Imine Reduction. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201503233] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
28
|
Mahdi T, Stephan DW. Facile Protocol for Catalytic Frustrated Lewis Pair Hydrogenation and Reductive Deoxygenation of Ketones and Aldehydes. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201503087] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
29
|
Mahdi T, Stephan DW. Facile Protocol for Catalytic Frustrated Lewis Pair Hydrogenation and Reductive Deoxygenation of Ketones and Aldehydes. Angew Chem Int Ed Engl 2015; 54:8511-4. [PMID: 26038152 DOI: 10.1002/anie.201503087] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Indexed: 11/10/2022]
Abstract
A series of ketones and aldehydes are reduced in toluene under H2 in the presence of 5 mol % B(C6F5)3 and either cyclodextrin or molecular sieves affording a facile metal-free protocol for reduction to alcohols. Similar treatment of aryl ketones resulted in metal-free deoxygenation yielding aromatic hydrocarbons.
Collapse
Affiliation(s)
- Tayseer Mahdi
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto, Ontario, M5S 3H6 (Canada)
| | - Douglas W Stephan
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto, Ontario, M5S 3H6 (Canada).
| |
Collapse
|