1
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Patra SG. Asymmetric catalysis by chiral FLPs: A computational mini-review. Chirality 2024; 36:e23671. [PMID: 38660756 DOI: 10.1002/chir.23671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 03/21/2024] [Accepted: 04/07/2024] [Indexed: 04/26/2024]
Abstract
Steric hindrance in Lewis acid (LA) and Lewis base (LB) obstruct the Lewis acid-base adduct formation, and the pair was termed as frustrated Lewis pair (FLP). In the past 16 years, the field of enantioselective catalysis by chiral FLPs has been slowly growing. It was shown that chiral LAs are significant as they are involved in the hydrogen transfer (HT) step to the imine, resulting in enantioselectivity. After H2 activation, the borohydride can exist in a number of plausible conformations and their stability is governed by the presence of noncovalent interaction through C-H····π and π····π interactions. However, LBs are not ideal for asymmetric induction as they compete with the imine substrate as a counter LB. Further, the proton transfer from chiral LB to the imine does not induce any chirality as chirality develops in the HT step. However, intramolecular FLPs with chiral scaffold are very efficient as they possess an optimum distance between LA and LB, which facilitates the H2 activation but precludes the adduct formation of the small molecules substrate with the LA component. This mini-review summarizes computational investigation involving chiral LA and LB, and discusses intramolecular FLPs in the enantioselective catalysis.
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Affiliation(s)
- Shanti Gopal Patra
- Department of Chemistry, National Institute of Technology Silchar, Silchar, India
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2
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Unveiling novel reactivity of P/Al frustrated Lewis pair: ring size-dependent activation of cyclic ethers/thioethers and CO2 insertion therein. J CHEM SCI 2022. [DOI: 10.1007/s12039-022-02119-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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3
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Mondal H, Patra SG, Chattaraj PK. Small molecule activation and dehydrogenation of an amine–borane system using frustrated Lewis pairs. Struct Chem 2022. [DOI: 10.1007/s11224-022-01934-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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4
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Possible C-F bond activation by B(C6F5)3/lutidine and Al(C6F5)3/lutidine frustrated Lewis pair: an in silico study. J CHEM SCI 2022. [DOI: 10.1007/s12039-021-02010-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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5
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Abraham JA, Mori S, Ishida M, Furuta H. Synthesis and Characterization of N-Fused Porphyrin Rhodium Complex with an Isomerized Cyclooctadiene Ligand. CHEM LETT 2021. [DOI: 10.1246/cl.210381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Jibin Alex Abraham
- Department of Applied Chemistry, Graduate School of Engineering, and Center for Molecular Systems, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Shigeki Mori
- Advanced Research Support Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Masatoshi Ishida
- Department of Applied Chemistry, Graduate School of Engineering, and Center for Molecular Systems, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Hiroyuki Furuta
- Department of Applied Chemistry, Graduate School of Engineering, and Center for Molecular Systems, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
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6
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Mondal H, Ghara M, Chattaraj PK. A computational investigation of the activation of allene (H2C = C = CHR; R = H, CH3, CN) by a frustrated phosphorous/boron Lewis pair. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138623] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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7
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Can a decrease in anti-aromaticity increase the dihydrogen activation ability of a frustrated phosphorous/borane Lewis pair?: a DFT study. Theor Chem Acc 2020. [DOI: 10.1007/s00214-020-02698-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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8
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Wech F, Hasenbeck M, Gellrich U. Semihydrogenation of Alkynes Catalyzed by a Pyridone Borane Complex: Frustrated Lewis Pair Reactivity and Boron-Ligand Cooperation in Concert. Chemistry 2020; 26:13445-13450. [PMID: 32242988 PMCID: PMC7693047 DOI: 10.1002/chem.202001276] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 04/01/2020] [Indexed: 11/11/2022]
Abstract
The metal‐free cis selective hydrogenation of alkynes catalyzed by a boroxypyridine is reported. A variety of internal alkynes are hydrogenated at 80 °C under 5 bar H2 with good yields and stereoselectivity. Furthermore, the catalyst described herein enables the first metal‐free semihydrogenation of terminal alkynes. Mechanistic investigations, substantiated by DFT computations, reveal that the mode of action by which the boroxypyridine activates H2 is reminiscent of the reactivity of an intramolecular frustrated Lewis pair. However, it is the change in the coordination mode of the boroxypyridine upon H2 activation that allows the dissociation of the formed pyridone borane complex and subsequent hydroboration of an alkyne. This change in the coordination mode upon bond activation is described by the term boron‐ligand cooperation.
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Affiliation(s)
- Felix Wech
- 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
| | - Urs Gellrich
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
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9
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Ghara M, Giri S, Chattaraj PK. Cycloaddition Reactions between H2C = CHR (R = H, CN, CH3) and a Cyclic P/B Frustrated Lewis Pair: A DFT Study. J Phys Chem A 2020; 124:4455-4462. [DOI: 10.1021/acs.jpca.0c02799] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Manas Ghara
- Department of Chemistry and Center for Theoretical Studies, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Santanab Giri
- Department of Applied Sciences and Humanities, Haldia Institute of Technology, Haldia 721657, India
| | - Pratim Kumar Chattaraj
- Department of Chemistry and Center for Theoretical Studies, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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10
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11
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Khan I, Reed‐Berendt BG, Melen RL, Morrill LC. FLP-Catalyzed Transfer Hydrogenation of Silyl Enol Ethers. Angew Chem Int Ed Engl 2018; 57:12356-12359. [PMID: 30106498 PMCID: PMC6207922 DOI: 10.1002/anie.201808800] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Indexed: 01/08/2023]
Abstract
Herein we report the first catalytic transfer hydrogenation of silyl enol ethers. This metal free approach employs tris(pentafluorophenyl)borane and 2,2,6,6-tetramethylpiperidine (TMP) as a commercially available FLP catalyst system and naturally occurring γ-terpinene as a dihydrogen surrogate. A variety of silyl enol ethers undergo efficient hydrogenation, with the reduced products isolated in excellent yields (29 examples, 82 % average yield).
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Affiliation(s)
- Imtiaz Khan
- School of ChemistryCardiff UniversityMain BuildingPark PlaceCardiffCF10 3ATUK
| | | | - Rebecca L. Melen
- School of ChemistryCardiff UniversityMain BuildingPark PlaceCardiffCF10 3ATUK
| | - Louis C. Morrill
- School of ChemistryCardiff UniversityMain BuildingPark PlaceCardiffCF10 3ATUK
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12
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13
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Wang Q, Chen J, Feng X, Du H. B(C6F5)3-catalyzed transfer hydrogenations of imines with Hantzsch esters. Org Biomol Chem 2018; 16:1448-1451. [DOI: 10.1039/c8ob00023a] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Transfer hydrogenations of imines with Hantzsch esters were realized using 0.1 mol% of B(C6F5)3, and up to 38% ee was obtained for asymmetric reactions.
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Affiliation(s)
- Qiaotian Wang
- Beijing National Laboratory of Molecular Sciences
- CAS Key Laboratory of Molecular Recognition and Function
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
| | - Jingjing Chen
- Beijing National Laboratory of Molecular Sciences
- CAS Key Laboratory of Molecular Recognition and Function
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
| | - Xiangqing Feng
- Beijing National Laboratory of Molecular Sciences
- CAS Key Laboratory of Molecular Recognition and Function
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
| | - Haifeng Du
- Beijing National Laboratory of Molecular Sciences
- CAS Key Laboratory of Molecular Recognition and Function
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
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14
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Skara G, De Vleeschouwer F, Geerlings P, De Proft F, Pinter B. Heterolytic Splitting of Molecular Hydrogen by Frustrated and Classical Lewis Pairs: A Unified Reactivity Concept. Sci Rep 2017; 7:16024. [PMID: 29167477 PMCID: PMC5700139 DOI: 10.1038/s41598-017-16244-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 11/09/2017] [Indexed: 12/20/2022] Open
Abstract
Using a set of state-of-the-art quantum chemical techniques we scrutinized the characteristically different reactivity of frustrated and classical Lewis pairs towards molecular hydrogen. The mechanisms and reaction profiles computed for the H2 splitting reaction of various Lewis pairs are in good agreement with the experimentally observed feasibility of H2 activation. More importantly, the analysis of activation parameters unambiguously revealed the existence of two reaction pathways through a low-energy and a high-energy transition state. An exhaustive scrutiny of these transition states, including their stability, geometry and electronic structure, reflects that the electronic rearrangement in low-energy transition states is fundamentally different from that of high-energy transition states. Our findings reveal that the widespread consensus mechanism of H2 splitting characterizes activation processes corresponding to high-energy transition states and, accordingly, is not operative for H2-activating systems. One of the criteria of H2-activation, actually, is the availability of a low-energy transition state that represents a different H2 splitting mechanism, in which the electrostatic field generated in the cavity of Lewis pair plays a critical role: to induce a strong polarization of H2 that facilities an efficient end-on acid-H2 interaction and to stabilize the charge separated "H+-H-" moiety in the transition state.
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Affiliation(s)
- Gabriella Skara
- Quantum Chemistry Group, Member of the QCMM VUB-UGent Alliance Research Group, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium
| | - Freija De Vleeschouwer
- Quantum Chemistry Group, Member of the QCMM VUB-UGent Alliance Research Group, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium.
| | - Paul Geerlings
- Quantum Chemistry Group, Member of the QCMM VUB-UGent Alliance Research Group, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium
| | - Frank De Proft
- Quantum Chemistry Group, Member of the QCMM VUB-UGent Alliance Research Group, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium
| | - Balazs Pinter
- Quantum Chemistry Group, Member of the QCMM VUB-UGent Alliance Research Group, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium.
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15
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Wang Q, Zhao W, He J, Zhang Y, Chen EYX. Living Ring-Opening Polymerization of Lactones by N-Heterocyclic Olefin/Al(C6F5)3 Lewis Pairs: Structures of Intermediates, Kinetics, and Mechanism. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b02398] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Qianyi Wang
- State
Key Laboratory of Supramolecular Structure and Materials, College
of Chemistry, Jilin University, Changchun 130012, China
| | - Wuchao Zhao
- State
Key Laboratory of Supramolecular Structure and Materials, College
of Chemistry, Jilin University, Changchun 130012, China
| | - Jianghua He
- State
Key Laboratory of Supramolecular Structure and Materials, College
of Chemistry, Jilin University, Changchun 130012, China
| | - Yuetao Zhang
- State
Key Laboratory of Supramolecular Structure and Materials, College
of Chemistry, Jilin University, Changchun 130012, China
| | - Eugene Y.-X. Chen
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
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16
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Wei S, Feng X, Du H. A metal-free hydrogenation of 3-substituted 2H-1,4-benzoxazines. Org Biomol Chem 2016; 14:8026-9. [PMID: 27501824 DOI: 10.1039/c6ob01556e] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A metal-free hydrogenation of 3-substituted 2H-1,4-benzoxazines has been successfully realized with 2.5 mol% of B(C6F5)3 as a catalyst to furnish a variety of 3,4-dihydro-2H-1,4-benzoxazines in 93-99% yields. Up to 42% ee was also achieved for the asymmetric hydrogenation with the use of a chiral diene and HB(C6F5)2.
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Affiliation(s)
- Simin Wei
- Beijing National Laboratory of Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
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17
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Almas QL, Keefe BL, Profitt T, Pearson JK. Choosing an appropriate model chemistry in a big data context: Application to dative bonding. COMPUT THEOR CHEM 2016. [DOI: 10.1016/j.comptc.2016.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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18
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Zhang C, Lv X, Lu G, Wang ZX. Metal-free homolytic hydrogen activation: a quest through density functional theory computations. NEW J CHEM 2016. [DOI: 10.1039/c6nj00557h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
DFT computations reveal that heavier analogs of 1,3-butadiene could activate H2homolyticallyvia1,4-addition.
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Affiliation(s)
- Chenggen Zhang
- Department of Chemistry and Materials Science
- Langfang Teachers University
- Langfang 065000
- People's Republic of China
| | - Xiangying Lv
- School of Environment
- Henan Normal University
- Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control
- Ministry of Education
- Henan Key Laboratory for Environmental Pollution Control
| | - Gang Lu
- State Key Laboratory of Structural Chemistry
- Fujian Institute of Research on the Structure of Matter
- Chinese Academy of Sciences
- Fuzhou
- China
| | - Zhi-Xiang Wang
- School of Chemistry and Chemical Engineering
- University of the Chinese Academy of Sciences
- Beijing 100049
- China
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19
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Cardenas AJP, Hasegawa Y, Kehr G, Warren TH, Erker G. Cooperative 1,1-addition reactions of vicinal phosphane/borane frustrated Lewis pairs. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2015.01.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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20
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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.
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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).
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21
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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]
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22
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Chen J, Chen EXY. Reactivity of Amine/E(C6F5)3 (E = B, Al) Lewis Pairs toward Linear and Cyclic Acrylic Monomers: Hydrogenation vs. Polymerization. Molecules 2015; 20:9575-90. [PMID: 26016548 PMCID: PMC6272166 DOI: 10.3390/molecules20069575] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 05/20/2015] [Accepted: 05/21/2015] [Indexed: 11/23/2022] Open
Abstract
This work reveals the contrasting reactivity of amine/E(C6F5)3 (E = B, Al) Lewis pairs toward linear and cyclic acrylic monomers, methyl methacrylate (MMA) and biorenewable γ-methyl-α-methylene-γ-butyrolactone (γMMBL). While mixing of 2,2,6,6-tetramethylpiperidine (TMP) and B(C6F5)3 leads to a frustrated Lewis pair (FLP), Et3N reacts with B(C6F5)3 to form disproportionation products, ammonium hydridoborate ionic pair and iminium zwitterion. On the other hand, the stoichiometric reaction of either TMP or Et3N with Al(C6F5)3 leads to clean formation of a classic Lewis adduct (CLA). Neither TMP nor Et3N, when paired with E(C6F5)3, polymerizes MMA, but the Et3N/2B(C6F5)3 pair promotes transfer hydrogenation of MMA to form methyl isobutyrate. In contrast, the amine/E(C6F5)3 pairs promote rapid polymerization of γMMBL carrying the more reactive exocyclic methylene moiety, achieving full conversion in less than 3 min even at a low catalyst loading of 0.0625 mol %. TMP is more effective than Et3N for the polymerization when paired with either the borane or the alane, while the alane exhibits higher polymerization activity than the borane when paired with Et3N. Overall, the TMP/Al(C6F5)3 system exhibits the highest polymerization activity, achieving a maximum turn-over frequency of 96,000 h-1 at 0.125 mol % of catalyst loading, producing high molecular weight PγMMBL with Mn = 1.29 × 105 g∙mol-1.
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Affiliation(s)
- Jiawei Chen
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA
| | - Eugene X-Y Chen
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA.
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Abstract
CONSPECTUS: Frustrated Lewis pair (FLP) chemistry has emerged in the past decade as a strategy that enables main-group compounds to activate small molecules. This concept is based on the notion that combinations of Lewis acids and bases that are sterically prevented from forming classical Lewis acid-base adducts have Lewis acidity and basicity available for interaction with a third molecule. This concept has been applied to stoichiometric reactivity and then extended to catalysis. This Account describes three examples of such developments: hydrogenation, hydroamination, and CO2 reduction. The most dramatic finding from FLP chemistry was the discovery that FLPs can activate H2, thus countering the long-existing dogma that metals are required for such activation. This finding of stoichiometric reactivity was subsequently evolved to employ simple main-group species as catalysts in hydrogenations. While the initial studies focused on imines, subsequent studies uncovered FLP catalysts for a variety of organic substrates, including enamines, silyl enol ethers, olefins, and alkynes. Moreover, FLP reductions of aromatic anilines and N-heterocycles have been developed, while very recent extensions have uncovered the utility of FLP catalysts for ketone reductions. FLPs have also been shown to undergo stoichiometric reactivity with terminal alkynes. Typically, either deprotonation or FLP addition reaction products are observed, depending largely on the basicity of the Lewis base. While a variety of acid/base combinations have been exploited to afford a variety of zwitterionic products, this reactivity can also be extended to catalysis. When secondary aryl amines are employed, hydroamination of alkynes can be performed catalytically, providing a facile, metal-free route to enamines. In a similar fashion, initial studies of FLPs with CO2 demonstrated their ability to capture this greenhouse gas. Again, modification of the constituents of the FLP led to the discovery of reaction systems that demonstrated stoichiometric reduction of CO2 to either methanol or CO. Further modification led to the development of catalytic systems for the reduction of CO2 by hydrosilylation and hydroboration or deoxygenation. As each of these areas of FLP chemistry has advanced from the observation of unusual stoichiometric reactions to catalytic processes, it is clear that the concept of FLPs provides a new strategy for the design and application of main-group chemistry and the development of new metal-free catalytic processes.
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Affiliation(s)
- Douglas W. Stephan
- Department of Chemistry, University of Toronto, 80 St. George
Street, Toronto, Ontario, Canada M5S 3H6
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Lindqvist M, Borre K, Axenov K, Kótai B, Nieger M, Leskelä M, Pápai I, Repo T. Chiral molecular tweezers: synthesis and reactivity in asymmetric hydrogenation. J Am Chem Soc 2015; 137:4038-41. [PMID: 25636083 DOI: 10.1021/ja512658m] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report the synthesis and reactivity of a chiral aminoborane displaying both rapid and reversible H2 activation. The catalyst shows exceptional reactivity in asymmetric hydrogenation of enamines and unhindered imines with stereoselectivities of up to 99% ee. DFT analysis of the reaction mechanism pointed to the importance of both repulsive steric and stabilizing intermolecular non-covalent forces in the stereodetermining hydride transfer step of the catalytic cycle.
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Affiliation(s)
- Markus Lindqvist
- †Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland
| | - Katja Borre
- †Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland
| | - Kirill Axenov
- †Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland
| | - Bianka Kótai
- ‡Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, P.O. Box 286, H-1519 Budapest, Hungary
| | - Martin Nieger
- †Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland
| | - Markku Leskelä
- †Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland
| | - Imre Pápai
- ‡Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, P.O. Box 286, H-1519 Budapest, Hungary
| | - Timo Repo
- †Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland
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25
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Farrell JM, Posaratnanathan RT, Stephan DW. A family of N-heterocyclic carbene-stabilized borenium ions for metal-free imine hydrogenation catalysis. Chem Sci 2015; 6:2010-2015. [PMID: 29449920 PMCID: PMC5810240 DOI: 10.1039/c4sc03675a] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 01/26/2015] [Indexed: 12/13/2022] Open
Abstract
Room-temperature metal-free hydrogenation catalysis.
This manuscript probes the steric and electronic attributes that lead to “frustrated Lewis pair” (FLP)-type catalysis of imine hydrogenation by borenium ions. Hydride abstraction from (ItBu)HB(C6F5)22 prompts intramolecular C–H bond activation to give (CHN)2(tBu) (CMe2CH2)CB(C6F5)23, defining an upper limit of Lewis acidity for FLP hydrogenation catalysis. A series of seven N-heterocyclic carbene–borane (NHC–borane) adducts ((R′CNR)2C)(HBC8H14) (R′ = H, R = dipp 4a, Mes 5a, Me 8a; R = Me R′ = Me 9a, Cl, 10a) and ((HC)2(NMe)(NR)C)(HBC8H14) (R = tBu, 6a, Ph 7a) are prepared and converted to corresponding borenium salts. These species are evaluated as catalysts for metal-free imine hydrogenation at room temperature. Systematic tuning of the carbene donor for the hydrogenation of archetypal substrate N-benzylidene-tert-butylamine achieves the highest reported turn-over frequencies for FLP-catalyzed hydrogenation at amongst the lowest reported catalyst loadings. The most active NHC–borenium catalyst of this series, derived from 10a, is readily isolable, crystallographically characterized and shown to be effective in the hydrogenation catalysis of functional group-containing imines and N-heterocycles.
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Affiliation(s)
- Jeffrey M Farrell
- Department of Chemistry , University of Toronto , 80 St. George St. , Toronto , ON M5H3H6 , Canada .
| | - Roy T Posaratnanathan
- Department of Chemistry , University of Toronto , 80 St. George St. , Toronto , ON M5H3H6 , Canada .
| | - Douglas W Stephan
- Department of Chemistry , University of Toronto , 80 St. George St. , Toronto , ON M5H3H6 , Canada . .,Department of Chemistry , Faculty of Science , King Abdulaziz University , Jeddah , Saudi Arabia
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26
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Chen J, Chen EYX. Lewis Pair Polymerization of Acrylic Monomers byN-Heterocyclic Carbenes and B(C6F5)3. Isr J Chem 2015. [DOI: 10.1002/ijch.201400136] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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27
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Li G, Liu Y, Du H. B(C6F5)3-catalyzed metal-free hydrogenation of naphthylamines. Org Biomol Chem 2015; 13:2875-8. [DOI: 10.1039/c5ob00009b] [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
A catalytic metal-free hydrogenation of naphthylamines using B(C6F5)3 was achieved under mild conditions for the first time to furnish tetrahydronaphthylamines in high yields.
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Affiliation(s)
- Gen Li
- Beijing National Laboratory of Molecular Sciences
- CAS Key Laboratory of Molecular Recognition and Function
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
| | - Yongbing Liu
- Beijing National Laboratory of Molecular Sciences
- CAS Key Laboratory of Molecular Recognition and Function
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
| | - Haifeng Du
- Beijing National Laboratory of Molecular Sciences
- CAS Key Laboratory of Molecular Recognition and Function
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
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28
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Abstract
This Perspective article reviews the recent developments in reduction reactions catalysed by main-group element compounds.
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Affiliation(s)
- K. Revunova
- Chemistry Department
- Brock University
- Ontario
- Canada
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29
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Metal-free asymmetric hydrogenation and hydrosilylation catalyzed by frustrated Lewis pairs. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.10.138] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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30
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He J, Zhang Y, Falivene L, Caporaso L, Cavallo L, Chen EYX. Chain Propagation and Termination Mechanisms for Polymerization of Conjugated Polar Alkenes by [Al]-Based Frustrated Lewis Pairs. Macromolecules 2014. [DOI: 10.1021/ma5019389] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Jianghua He
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Yuetao Zhang
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
- State
Key Laboratory of Supramolecular Structure and Materials, College
of Chemistry, Jilin University, Changchun 130012, China
| | - Laura Falivene
- Physical
Sciences and Engineering Division, Kaust Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
- Dipartimento
di Chimica e Biologia, Università di Salerno, Via Papa
Paolo Giovanni II, I-84084 Fisciano, Italy
| | - Lucia Caporaso
- Dipartimento
di Chimica e Biologia, Università di Salerno, Via Papa
Paolo Giovanni II, I-84084 Fisciano, Italy
| | - Luigi Cavallo
- Physical
Sciences and Engineering Division, Kaust Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
- Dipartimento
di Chimica e Biologia, Università di Salerno, Via Papa
Paolo Giovanni II, I-84084 Fisciano, Italy
| | - Eugene Y.-X. Chen
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
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31
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Wei S, Du H. A Highly Enantioselective Hydrogenation of Silyl Enol Ethers Catalyzed by Chiral Frustrated Lewis Pairs. J Am Chem Soc 2014; 136:12261-4. [DOI: 10.1021/ja507536n] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- 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
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32
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Hounjet LJ, Stephan DW. Hydrogenation by Frustrated Lewis Pairs: Main Group Alternatives to Transition Metal Catalysts? Org Process Res Dev 2014. [DOI: 10.1021/op400315m] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lindsay J. Hounjet
- Department of Chemistry, University of Toronto, 80 St. George
Street, Toronto, Ontario, Canada M5S 3H6
| | - Douglas W. Stephan
- Department of Chemistry, University of Toronto, 80 St. George
Street, Toronto, Ontario, Canada M5S 3H6
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33
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Wang X, Kehr G, Daniliuc CG, Erker G. Internal Adduct Formation of Active Intramolecular C4-bridged Frustrated Phosphane/Borane Lewis Pairs. J Am Chem Soc 2014; 136:3293-303. [DOI: 10.1021/ja413060u] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Xiaowu Wang
- Organisch-Chemisches Institut der Universität Münster, Correnstrasse 40, 48149 Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut der Universität Münster, Correnstrasse 40, 48149 Münster, Germany
| | - Constantin G. Daniliuc
- Organisch-Chemisches Institut der Universität Münster, Correnstrasse 40, 48149 Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut der Universität Münster, Correnstrasse 40, 48149 Münster, Germany
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34
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Erdmann M, Wiegand T, Blumenberg J, Eckert H, Ren J, Daniliuc CG, Kehr G, Erker G. Formation, structural characterization, and reactions of a unique cyclotrimeric vicinal Lewis pair containing (C6F5)2P-Lewis base and (C6F5)BH-Lewis acid components. Dalton Trans 2014; 43:15159-69. [DOI: 10.1039/c4dt02081b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A unique vicinal Lewis pair cyclotrimer has been synthesized and characterized with respect to its structure and reactivity.
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Affiliation(s)
- Markus Erdmann
- Organisch-Chemisches Institut
- WWU Münster
- D 48149 Münster, Germany
| | - Thomas Wiegand
- Institut für Physikalische Chemie and Graduate School of Chemistry
- WWU Münster
- D 48149 Münster, Germany
| | - Jonas Blumenberg
- Organisch-Chemisches Institut
- WWU Münster
- D 48149 Münster, Germany
| | - Hellmut Eckert
- Institut für Physikalische Chemie and Graduate School of Chemistry
- WWU Münster
- D 48149 Münster, Germany
| | - Jinjun Ren
- Institut für Physikalische Chemie and Graduate School of Chemistry
- WWU Münster
- D 48149 Münster, Germany
| | | | - Gerald Kehr
- Organisch-Chemisches Institut
- WWU Münster
- D 48149 Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut
- WWU Münster
- D 48149 Münster, Germany
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35
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Hatnean JA, Thomson JW, Chase PA, Stephan DW. Imine hydrogenation by alkylaluminum catalysts. Chem Commun (Camb) 2014; 50:301-3. [DOI: 10.1039/c3cc47889k] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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36
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The Mannich Route to Amino-Functionalized [3]Ferrocenophanes. ADVANCES IN ORGANOMETALLIC CHEMISTRY 2014. [DOI: 10.1016/b978-0-12-800976-5.00004-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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37
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Rocchigiani L, Ciancaleoni G, Zuccaccia C, Macchioni A. Probing the Association of Frustrated Phosphine–Borane Lewis Pairs in Solution by NMR Spectroscopy. J Am Chem Soc 2013; 136:112-5. [DOI: 10.1021/ja4119169] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Luca Rocchigiani
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Gianluca Ciancaleoni
- Istituto
del CNR di Science e Tecnologie Molecolari, c/o Dipartimento di Chimica,
Biologia e Biotecnologie, Università degli Studi di Perugia, I-06123 Perugia, Italy
| | - Cristiano Zuccaccia
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Alceo Macchioni
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Via Elce di Sotto 8, I-06123 Perugia, Italy
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38
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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.
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Affiliation(s)
- Muhammad Sajid
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität , Corrensstraße 40, 48149 Münster, Germany
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39
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40
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Affiliation(s)
- Matti Reißmann
- Institut für
Chemie, Carl von Ossietzky Universität Oldenburg, Carl von Ossietzky
Straße 9-11, D-26129 Oldenburg, Federal Republic of Germany
| | - André Schäfer
- Institut für
Chemie, Carl von Ossietzky Universität Oldenburg, Carl von Ossietzky
Straße 9-11, D-26129 Oldenburg, Federal Republic of Germany
| | - Sebastian Jung
- Institut für
Chemie, Carl von Ossietzky Universität Oldenburg, Carl von Ossietzky
Straße 9-11, D-26129 Oldenburg, Federal Republic of Germany
| | - Thomas Müller
- Institut für
Chemie, Carl von Ossietzky Universität Oldenburg, Carl von Ossietzky
Straße 9-11, D-26129 Oldenburg, Federal Republic of Germany
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41
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Liu Y, Du H. Metal-Free Borane-Catalyzed Highly Stereoselective Hydrogenation of Pyridines. J Am Chem Soc 2013; 135:12968-71. [DOI: 10.1021/ja406761j] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Yongbing Liu
- Beijing National Laboratory of 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 of Molecular Sciences,
CAS Key Laboratory of Molecular Recognition and Function, Institute
of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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42
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Lindqvist M, Axenov K, Nieger M, Räisänen M, Leskelä M, Repo T. Frustrated Lewis pair chemistry of chiral (+)-camphor-based aminoboranes. Chemistry 2013; 19:10412-8. [PMID: 23788132 DOI: 10.1002/chem.201300462] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Indexed: 11/08/2022]
Abstract
Dimethylamino-(+)-camphorenamine reacted with an equimolar amount of Piers' borane, HB(C6F5)2, to give the corresponding iminium-hydroborate zwitterionic salt. Being in equilibrium with the parent enamine-HB(C6F5)2 N-B pair, this salt was able to split hydrogen heterolytically, hydrogenating the iminium group in the molecule. Detailed studies revealed that the hydrogen splitting in this reaction proceeded through an intermolecular pathway leading to a bornylamine-HB(C6F5)2 adduct. When the starting enamine is present in excess over HB(C6F5)2, the produced bornylamine-HB(C6F5)2 adduct breaks up, eliminating free bornylamine and forming the initial camphorenamine-HB(C6F5)2 pair. This results in hydrogenation of the camphorenamine framework in a catalytic fashion.
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Affiliation(s)
- Markus Lindqvist
- Department of Chemistry, Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, 00014, Finland
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43
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Liu Y, Du H. Chiral Dienes as “Ligands” for Borane-Catalyzed Metal-Free Asymmetric Hydrogenation of Imines. J Am Chem Soc 2013; 135:6810-3. [DOI: 10.1021/ja4025808] [Citation(s) in RCA: 184] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yongbing Liu
- 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
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44
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Clark ER, Del Grosso A, Ingleson MJ. The hydride-ion affinity of borenium cations and their propensity to activate H2 in frustrated Lewis pairs. Chemistry 2013; 19:2462-6. [PMID: 23296951 DOI: 10.1002/chem.201203318] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Indexed: 11/11/2022]
Abstract
A range of frustrated Lewis pairs (FLPs) containing borenium cations have been synthesised. The catechol (Cat)-ligated borenium cation [CatB(PtBu(3))](+) has a lower hydride-ion affinity (HIA) than B(C(6)F(5))(3). This resulted in H(2) activation being energetically unfavourable in a FLP with the strong base PtBu(3). However, ligand disproportionation of CatBH(PtBu(3)) at 100 °C enabled trapping of H(2) activation products. DFT calculations at the M06-2X/6-311G(d,p)/PCM (CH(2)Cl(2)) level revealed that replacing catechol with chlorides significantly increases the chloride-ion affinity (CIA) and HIA. Dichloro-borenium cations, [Cl(2)B(amine)](+), were calculated to have considerably greater HIA than B(C(6)F(5))(3). Control reactions confirmed that the HIA calculations can be used to successfully predict hydride-transfer reactivity between borenium cations and neutral boranes. The borenium cations [Y(Cl)B(2,6-lutidine)](+) (Y = Cl or Ph) form FLPs with P(mesityl)(3) that undergo slow deprotonation of an ortho-methyl of lutidine at 20 °C to form the four-membered boracycles [(CH(2){NC(5)H(3)Me})B(Cl)Y] and [HPMes(3)](+). When equimolar [Y(Cl)B(2,6-lutidine)](+)/P(mesityl)(3) was heated under H(2) (4 atm), heterolytic cleavage of dihydrogen was competitive with boracycle formation.
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Affiliation(s)
- Ewan R Clark
- Department of Chemistry, University of Manchester, Manchester, M13 9PL, UK
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45
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46
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Annibale VT, Song D. Multidentate actor ligands as versatile platforms for small molecule activation and catalysis. RSC Adv 2013. [DOI: 10.1039/c3ra40618k] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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47
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Erdmann M, Rösener C, Holtrichter-Rößmann T, Daniliuc CG, Fröhlich R, Uhl W, Würthwein EU, Kehr G, Erker G. Functional group chemistry at intramolecular frustrated Lewis pairs: substituent exchange at the Lewis acid site with 9-BBN. Dalton Trans 2013; 42:709-18. [DOI: 10.1039/c2dt31737k] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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48
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Chen D, Klankermayer J. Frustrated Lewis Pairs: from dihydrogen activation to asymmetric catalysis. Top Curr Chem (Cham) 2013; 334:1-26. [PMID: 23408275 DOI: 10.1007/128_2012_402] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The non-self-quenched property of Frustrated Lewis Pairs (FLPs) contradicts the classical Lewis acid-base theory, but this peculiarity offers unprecedented possibilities for the activation of small molecules. Among all of their fascinating applications, FLP mediated hydrogen activation and the associated catalytic hydrogenations are currently considered as the most intriguing illustration of their reactivity. The FLPs enabled the catalytic reduction of a wide range of substrates with molecular hydrogen and tuning of the structural properties of the FLP partners allowed broadening of the substrate scope. Based on detailed mechanistic knowledge, FLP based asymmetric hydrogenation of various substrates could be achieved with high enantioselectivities. More importantly, FLP based enantioselective catalysis is not limited to the field of asymmetric hydrogenation, and other exciting catalytic applications have already appeared.
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Affiliation(s)
- Dianjun Chen
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany
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49
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Schwendemann S, Oishi S, Saito S, Fröhlich R, Kehr G, Erker G. Reaction of an “Invisible” Frustrated N/B Lewis Pair with Dihydrogen. Chem Asian J 2012; 8:212-7. [DOI: 10.1002/asia.201200776] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Indexed: 11/09/2022]
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50
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Farrell JM, Hatnean JA, Stephan DW. Activation of hydrogen and hydrogenation catalysis by a borenium cation. J Am Chem Soc 2012; 134:15728-31. [PMID: 22931196 DOI: 10.1021/ja307995f] [Citation(s) in RCA: 213] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The readily prepared borenium salt [(IiPr(2))(BC(8)H(14))][B(C(6)F(5))(4)] (2) [IiPr(2) = C(3)H(2)(NiPr)(2)] is shown to activate H(2) heterolytically in the presence of tBu(3)P. Compound 2 also acts as a catalyst for the metal-free hydrogenation of imines and enamines at room temperature.
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Affiliation(s)
- Jeffrey M Farrell
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, Canada M5S 3H6
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