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Luo J, Montag M, Milstein D. Metal-Ligand Cooperation with Thiols as Transient Cooperative Ligands: Acceleration and Inhibition Effects in (De)Hydrogenation Reactions. Acc Chem Res 2024; 57:1709-1721. [PMID: 38833580 PMCID: PMC11191399 DOI: 10.1021/acs.accounts.4c00198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/13/2024] [Accepted: 05/15/2024] [Indexed: 06/06/2024]
Abstract
ConspectusOver the past two decades, we have developed a series of pincer-type transition metal complexes capable of activating strong covalent bonds through a mode of reactivity known as metal-ligand cooperation (MLC). In such systems, an incoming substrate molecule simultaneously interacts with both the metal center and ligand backbone, with one part of the molecule reacting at the metal center and another part at the ligand. The majority of these complexes feature pincer ligands with a pyridine core, and undergo MLC through reversible dearomatization/aromatization of this pyridine moiety. This MLC platform has enabled us to perform a variety of catalytic dehydrogenation, hydrogenation, and related reactions, with high efficiency and selectivity under relatively mild conditions.In a typical catalytic complex that operates through MLC, the cooperative ligand remains coordinated to the metal center throughout the entire catalytic process, and this complex is the only catalytic species involved in the reaction. As part of our ongoing efforts to develop new catalytic systems featuring MLC, we have recently introduced the concept of transient cooperative ligand (TCL), i.e., a ligand that is capable of MLC when coordinated to a metal center, but the coordination of which is reversible rather than permanent. We have thus far employed thiol(ate)s as TCLs, in conjunction with an acridanide-based ruthenium(II)-pincer catalyst, and this has resulted in remarkable acceleration and inhibition effects in various hydrogenation and dehydrogenation reactions. A cooperative thiol(ate) ligand can be installed in situ by the simple addition of an appropriate thiol in an amount equivalent to the catalyst, and this has been repeatedly shown to enable efficient bond activation by MLC without the need for other additives, such as base. The use of an ancillary thiol ligand that is not fixed to the pincer backbone allows the catalytic system to benefit from a high degree of tunability, easily implemented by varying the added thiol. Importantly, thiols are coordinatively labile enough under typical catalytic conditions to leave a meaningful portion of the catalyst in its original unsaturated form, thereby allowing it to carry out its own characteristic catalytic activity. This generates two coexisting catalyst populations─one that contains a thiol(ate) ligand and another that does not─and this may lead to different catalytic outcomes, namely, enhancement of the original catalytic activity, inhibition of this activity, or the occurrence of diverging reactivities within the same catalytic reaction mixture. These thiol effects have enabled us to achieve a series of unique transformations, such as thiol-accelerated base-free aqueous methanol reforming, controlled stereodivergent semihydrogenation of alkynes using thiol as a reversible catalyst inhibitor, and hydrogenative perdeuteration of C═C bonds without using D2, enabled by a combination of thiol-induced acceleration and inhibition. We have also successfully realized the unprecedented formation of thioesters through dehydrogenative coupling of alcohols and thiols, as well as the hydrogenation of organosulfur compounds, wherein the cooperative thiol serves as a reactant or product. In this Account, we present an overview of the TCL concept and its various applications using thiols.
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Affiliation(s)
- Jie Luo
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot 7610001, Israel
| | - Michael Montag
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot 7610001, Israel
| | - David Milstein
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot 7610001, Israel
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2
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Ke Z, Wang Y, Zhao Y, Tang M, Zeng W, Wang Y, Chang X, Han B, Liu Z. Ionic-Liquid Hydrogen-Bonding Promoted Alcohols Amination over Cobalt Catalyst via Dihydrogen Autotransfer Mechanism. CHEMSUSCHEM 2023; 16:e202300513. [PMID: 37191041 DOI: 10.1002/cssc.202300513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/15/2023] [Accepted: 05/16/2023] [Indexed: 05/17/2023]
Abstract
Higher amines are important high-valuable chemicals with wide applications, and amination of alcohols is a green route to them, which however generally suffers from harsh reaction conditions and use of equivalent base. Herein, we report an ionic-liquid (IL) hydrogen-bonding promoted dihydrogen autotransfer strategy for amination of alcohols to higher amines over cobalt catalyst under base-free conditions. Co(BF4 )2 ⋅ 6 H2 O complexed with triphos and IL (e. g., tetrabutylphosphonium tetrafluoroborate, [P4444 ][BF4 ]) shows high performances for the reaction and is tolerant of a wide scope of amines and alcohols, affording higher amines in good to excellent yields. Mechanism investigation indicates that the [BF4 ]- anion activates the alcohol via hydrogen bonding, promoting transfer of both hydroxyl H and α-H atoms of alcohol to the cobalt catalyst to form an aldehyde intermediate and cobalt dihydride complex, which are involved in the subsequent reductive amination. This strategy provides a green and effective route for alcohol amination, which may have promising applications in alcohol-involved alkylation reactions.
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Affiliation(s)
- Zhengang Ke
- Institute of Chemistry, Chinese Academy of Sciences, No. 2, Zhongguancun Beiyijie, Beijing, 100190, China
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi, China
| | - Yuepeng Wang
- Institute of Chemistry, Chinese Academy of Sciences, No. 2, Zhongguancun Beiyijie, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yanfei Zhao
- Institute of Chemistry, Chinese Academy of Sciences, No. 2, Zhongguancun Beiyijie, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Minhao Tang
- Institute of Chemistry, Chinese Academy of Sciences, No. 2, Zhongguancun Beiyijie, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wei Zeng
- Institute of Chemistry, Chinese Academy of Sciences, No. 2, Zhongguancun Beiyijie, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ying Wang
- Institute of Chemistry, Chinese Academy of Sciences, No. 2, Zhongguancun Beiyijie, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaoqian Chang
- Institute of Chemistry, Chinese Academy of Sciences, No. 2, Zhongguancun Beiyijie, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Buxing Han
- Institute of Chemistry, Chinese Academy of Sciences, No. 2, Zhongguancun Beiyijie, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhimin Liu
- Institute of Chemistry, Chinese Academy of Sciences, No. 2, Zhongguancun Beiyijie, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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3
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Sustainable amidation through acceptorless dehydrogenative coupling by pincer-type catalysts: recent advances. PURE APPL CHEM 2023. [DOI: 10.1515/pac-2022-1101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Abstract
The amide functional group is ubiquitous in living organisms, and is of particular importance in bioactive compounds and pharmaceuticals. Because of the prevalence and significance of the amide bond, considerable efforts have been invested throughout the years in developing new synthetic methodologies for its formation. Nevertheless, amide synthesis still largely relies on variants of the traditional condensation of carboxylic acids and amines, mediated by stoichiometric coupling reagents. This poses a sustainability challenge, since such reactions suffer from unfavorable atom and step economies, involve harmful chemicals and produce chemical waste. Hence, establishing sustainable approaches to amide synthesis is of great importance. Over the last two decades, we have developed homogeneous catalytic reactions for sustainable synthetic transformations, primarily based on transition metal complexes of pincer ligands. A considerable portion of these efforts has been devoted to acceptorless dehydrogenative coupling, including that of alcohols and amines through ruthenium-catalyzed reactions. These latter processes generate amides without resorting to coupling reagents and typically produce no waste, with their only byproduct being H2 gas, which is itself a valuable resource. In the present review, we chronicle our progress in this area of research since 2014. This includes the use of water and ammonia as amidation reagents, expanding the scope of amidation substrates and target amides, achieving milder reaction conditions, development of amidation-based liquid organic hydrogen carrier systems, and introduction of manganese-based catalysts.
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Zheng L, Mei W, Zou X, Zhong Y, Wu Y, Deng L, Wang Y, Yang B, Guo W. DBU-Promoted Deaminative Thiolation of 1 H-Benzo[ d]imidazol-2-amines and Benzo[ d]oxazol-2-amines. J Org Chem 2023; 88:272-284. [PMID: 36521048 DOI: 10.1021/acs.joc.2c02297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A facile and efficient catalyst-/metal-/oxidant-free DBU-promoted deaminative thiolation reaction of 1H-benzo[d]imidazol-2-amines and benzo[d]oxazol-2-amines has been developed at room temperature conditions in a one-pot protocol. This practical three-component strategy represents a novel and environmentally friendly reaction pathway toward the straightforward synthesis of various 2-thio-1H-benzo[d]imidazoles and 2-thiobenzo[d]oxazoles using carbon disulfide as a sulfur source through C-N bond cleavage and C-S bond formation process. Different types of 1H-benzo[d]imidazol-2-amines, benzo[d]oxazol-2-amines, and organic bromides are suitable substrates. The gram-scale and late-stage modification experiments provide the potential applications based on this methodology in the field of organic and medicinal chemistry.
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Affiliation(s)
- Lvyin Zheng
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Weijie Mei
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Xiaoying Zou
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Yumei Zhong
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Yingying Wu
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Lei Deng
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Yihan Wang
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Beining Yang
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Wei Guo
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
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Rhodium-Catalyzed Aerobic Conversion of 2-Diazo-1,3-dicarbonyls to Vicinal Tricarbonyl Compounds and Their In-Situ Stability Toward Oxidative Degradation. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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6
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Kar S, Milstein D. Oxidation of Organic Compounds Using Water as the Oxidant with H 2 Liberation Catalyzed by Molecular Metal Complexes. Acc Chem Res 2022; 55:2304-2315. [PMID: 35881940 PMCID: PMC9386904 DOI: 10.1021/acs.accounts.2c00328] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Oxidation reactions of organic compounds play a central role in both industrial chemical and material synthesis as well as in fine chemical and pharmaceutical synthesis. While traditional laboratory-scale oxidative syntheses have relied on the use of strong oxidizers, modern large-scale oxidation processes preferentially utilize air or pure O2 as an oxidant, with other oxidants such as hydrogen peroxide, nitric acid, and aqueous chlorine solution also being used in some processes. The use of molecular oxygen or air as an oxidant has been very attractive in recent decades because of the abundance of air and the lack of wasteful byproduct generation. Nevertheless, the use of high-pressure air or, in particular, pure oxygen can lead to serious safety concerns with improper handling and also necessitates the use of sophisticated high-pressure reactors for the processes.Several research groups, including ours, have investigated in recent times the possibility of carrying out catalytic oxidation reactions using water as the formal oxidant, with no added conventional oxidants. Along with the abundant availability of water, these processes also generate dihydrogen gas as the reaction coproduct, which is a highly valuable fuel. Several well-defined molecular metal complexes have been reported in recent years to catalyze these unusual oxidative reactions with water. A ruthenium bipyridine-based PNN pincer complex was reported by us to catalyze the oxidation of primary alcohols to carboxylate salts with alkaline water along with H2 liberation, followed by reports by other groups using other complexes as catalysts. At the same time, ruthenium-, iridium-, and rhodium-based complexes have been reported to catalyze aldehyde oxidation to carboxylic acids using water. Our group has combined the catalytic aqueous alcohol and aldehyde oxidation activity of a ruthenium complex to achieve the oxidation of biomass-derived renewable aldehydes such as furfural and 5-hydroxymethylfurfural (HMF) to furoic acid and furandicarboxylic acid (FDCA), respectively, using alkaline water as the oxidant, liberating H2. Ruthenium complexes with an acridine-based PNP ligand have also been employed by our group for the catalytic oxidation of amines to the corresponding lactams, or to carboxylic acids via a deaminative route, using water. Similarly, we also reported molecular complexes for the catalytic Markovnikov oxidation of alkenes to ketones using water, similar to Wacker-type oxidation, which, however, does not require any terminal oxidant and produces H2 as the coproduct. At the same time, the oxidation of enol ethers to the corresponding esters with water has also been reported. This account will highlight these recent advances where water was used as an oxidant to carry out selective oxidation reactions of organic compounds, catalyzed by well-defined molecular complexes, with H2 liberation. The oxidation of alcohols, aldehydes, amines, alkenes, and enol ethers will be discussed to provide an outlook toward other functional groups' oxidation. We hope that this will aid researchers in devising other oxidative dehydrogenative catalytic systems using water, complementing traditional oxidative processes involving strong oxidants and molecular oxygen.
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Luo J, Liang Y, Montag M, Diskin-Posner Y, Avram L, Milstein D. Controlled Selectivity through Reversible Inhibition of the Catalyst: Stereodivergent Semihydrogenation of Alkynes. J Am Chem Soc 2022; 144:13266-13275. [PMID: 35839274 PMCID: PMC9374179 DOI: 10.1021/jacs.2c04233] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Catalytic semihydrogenation of internal alkynes using
H2 is an attractive atom-economical route to various alkenes,
and its
stereocontrol has received widespread attention, both in homogeneous
and heterogeneous catalyses. Herein, a novel strategy is introduced,
whereby a poisoning catalytic thiol is employed as a reversible inhibitor
of a ruthenium catalyst, resulting in a controllable H2-based semihydrogenation of internal alkynes. Both (E)- and (Z)-alkenes were obtained efficiently and
highly selectively, under very mild conditions, using a single homogeneous
acridine-based ruthenium pincer catalyst. Mechanistic studies indicate
that the (Z)-alkene is the reaction intermediate
leading to the (E)-alkene and that the addition of
a catalytic amount of bidentate thiol impedes the Z/E isomerization step by forming stable ruthenium
thiol(ate) complexes, while still allowing the main hydrogenation
reaction to proceed. Thus, the absence or presence of catalytic thiol
controls the stereoselectivity of this alkyne semihydrogenation, affording
either the (E)-isomer as the final product or halting
the reaction at the (Z)-intermediate. The developed
system, which is also applied to the controllable isomerization of
a terminal alkene, demonstrates how metal catalysis with switchable
selectivity can be achieved by reversible inhibition of the catalyst
with a simple auxiliary additive.
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Affiliation(s)
- Jie Luo
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yaoyu Liang
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Michael Montag
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yael Diskin-Posner
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Liat Avram
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - David Milstein
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
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8
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Zheng Y, Long Y, Gong H, Xu J, Zhang C, Fu H, Zheng X, Chen H, Li R. Ruthenium-Catalyzed Divergent Acceptorless Dehydrogenative Coupling of 1,3-Diols with Arylhydrazines: Synthesis of Pyrazoles and 2-Pyrazolines. Org Lett 2022; 24:3878-3883. [PMID: 35609118 DOI: 10.1021/acs.orglett.2c01497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Herein, the divergent transformations of 1,3-diols with arylhydrazines via acceptorless dehydrogenative coupling reactions to selectively synthesize pyrazoles and 2-pyrazolines were reported, which were based on Ru3(CO)12/NHC-phosphine-phosphine catalytic systems. The reactions featured low catalyst loading, high selectivity, wide substrate scope, and good yields, with only water and hydrogen gas (H2) as the byproducts.
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Affiliation(s)
- Yanling Zheng
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
| | - Yang Long
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
| | - Huihua Gong
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
| | - Jiaqi Xu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
| | - Chunchun Zhang
- Analytical & Testing Center, Sichuan University, Chengdu 610064, People's Republic of China
| | - Haiyan Fu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
| | - Xueli Zheng
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
| | - Hua Chen
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
| | - Ruixiang Li
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
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9
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Nelmes GR, Brothers PJ, Hicks J. Convenient one‐pot synthesis and coordination chemistry of a bulky asymmetrical 9,10‐dihydroacridine‐based ligand. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202200127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Gareth R. Nelmes
- Australian National University Research School of Chemistry Sullivans Creek Road 2601 Acton AUSTRALIA
| | - Penelope J. Brothers
- Australian National University Research School of Chemistry Sullivans Creek Road 2601 Acton AUSTRALIA
| | - Jamie Hicks
- Australian National University Research School of Chemistry Sullivans Creek Road 2601 Acton AUSTRALIA
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Zeng K, Ye J, Meng X, Dechert S, Simon M, Gong S, Mata RA, Zhang K. Anomeric Stereoauxiliary Cleavage of the C−N Bond of
d
‐Glucosamine for the Preparation of Imidazo[1,5‐a]pyridines. Chemistry 2022; 28:e202200648. [PMID: 35319128 PMCID: PMC9325398 DOI: 10.1002/chem.202200648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Indexed: 11/13/2022]
Abstract
The targeted cleavage of the C−N bonds of alkyl primary amines in sustainable compounds of biomass according to a metal‐free pathway and the conjunction of nitrogen in the synthesis of imidazo[1,5‐a]pyridines are still highly challenging. Despite tremendous progress in the synthesis of imidazo[1,5‐a]pyridines over the past decade, many of them can still not be efficiently prepared. Herein, we report an anomeric stereoauxiliary approach for the synthesis of a wide range of imidazo[1,5‐a]pyridines after cleaving the C−N bond of d‐glucosamine (α‐2° amine) from biobased resources. This new approach expands the scope of readily accessible imidazo[1,5‐a]pyridines relative to existing state‐of‐the‐art methods. A key strategic advantage of this approach is that the α‐anomer of d‐glucosamine enables C−N bond cleavage via a seven‐membered ring transition state. By using this novel method, a series of imidazo[1,5‐a]pyridine derivatives (>80 examples) was synthesized from pyridine ketones (including para‐dipyridine ketone) and aldehydes (including para‐dialdehyde). Imidazo[1,5‐a]pyridine derivatives containing diverse important deuterated C(sp2)−H and C(sp3)−H bonds were also efficiently achieved.
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Affiliation(s)
- Kui Zeng
- Sustainable Materials and Chemistry Georg-August-University of Göttingen Büsgenweg 4 37077 Göttingen Germany
| | - Jin Ye
- Institute of Physical Chemistry Georg-August-University of Göttingen Tammannstraße 6 37077 Göttingen Germany
| | - Xintong Meng
- Sustainable Materials and Chemistry Georg-August-University of Göttingen Büsgenweg 4 37077 Göttingen Germany
| | - Sebastian Dechert
- Institute of Inorganic Chemistry Georg-August-University of Göttingen Tammannstraße 4 37077 Göttingen Germany
| | - Martin Simon
- Institute of Organic and Biomolecular Chemistry Georg-August-University of Göttingen Tammannstraße 2 37077 Göttingen Germany
| | - Shuaiyu Gong
- Sustainable Materials and Chemistry Georg-August-University of Göttingen Büsgenweg 4 37077 Göttingen Germany
| | - Ricardo A. Mata
- Institute of Physical Chemistry Georg-August-University of Göttingen Tammannstraße 6 37077 Göttingen Germany
| | - Kai Zhang
- Sustainable Materials and Chemistry Georg-August-University of Göttingen Büsgenweg 4 37077 Göttingen Germany
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Kar S, Milstein D. Sustainable catalysis with fluxional acridine-based PNP pincer complexes. Chem Commun (Camb) 2022; 58:3731-3746. [PMID: 35234797 PMCID: PMC8932388 DOI: 10.1039/d2cc00247g] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/23/2022] [Indexed: 12/14/2022]
Abstract
Because of the widespread use of fossil fuels and the resulting global warming, development of sustainable catalytic transformations is now more important than ever to obtain our desired fuels and building materials with the least carbon footprint and waste production. Many sustainable (de)hydrogenation reactions, including CO2 reduction, H2 carrier systems, and others, have been reported using molecular pincer complexes. A specific subset of pincer complexes containing a central acridine donor with flanking CH2PR2 ligands, known as acridine-based PNP pincer complexes, exhibit special reactivities that are not imitable by other PNP pincer complexes such as pyridine-based or (R2PCH2CH2)2NH type ligands. The goal of this article is to highlight the unique reactivities of acridine-based complexes and then investigate how these reactivities allow these complexes to catalyse many sustainable reactions that traditional pincer complexes cannot catalyse. To that end, we will initially go over the synthesis and structural features of acridine complexes, such as the labile coordination of the central N donor and the observed fac-mer fluxionality. Following that, distinct reactivity patterns of acridine-based complexes including their reactivity with acids and water will be discussed. Finally, we will discuss the reaction systems that have been developed with acridine complexes thus far, including the notable selective transformations of primary alcohols to primary amines using ammonia, N-heteroaromatic synthesis from alcohols and ammonia, oxidation reactions with water with H2 liberation, development of H2 carrier systems, and others, and conclude the article with future possible directions. We hope that the systemic study presented here will aid researchers in developing further sustainable reactions based on the unique acridine-based pincer complexes.
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Affiliation(s)
- Sayan Kar
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel.
| | - David Milstein
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel.
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12
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Kar S, Luo J, Rauch M, Diskin-Posner Y, Ben-David Y, Milstein D. Dehydrogenative ester synthesis from enol ethers and water with a ruthenium complex catalyzing two reactions in synergy. GREEN CHEMISTRY : AN INTERNATIONAL JOURNAL AND GREEN CHEMISTRY RESOURCE : GC 2022; 24:1481-1487. [PMID: 35308195 PMCID: PMC8860191 DOI: 10.1039/d1gc04574a] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
We report the dehydrogenative synthesis of esters from enol ethers using water as the formal oxidant, catalyzed by a newly developed ruthenium acridine-based PNP(Ph)-type complex. Mechanistic experiments and density functional theory (DFT) studies suggest that an inner-sphere stepwise coupled reaction pathway is operational instead of a more intuitive outer-sphere tandem hydration-dehydrogenation pathway.
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Affiliation(s)
- Sayan Kar
- Department of Molecular Chemistry and Materials Science, The Weizmann Institute of Science Rehovot 76100 Israel
| | - Jie Luo
- Department of Molecular Chemistry and Materials Science, The Weizmann Institute of Science Rehovot 76100 Israel
| | - Michael Rauch
- Department of Molecular Chemistry and Materials Science, The Weizmann Institute of Science Rehovot 76100 Israel
| | - Yael Diskin-Posner
- Department of Chemical Research Support, The Weizmann Institute of Science Rehovot 76100 Israel
| | - Yehoshoa Ben-David
- Department of Molecular Chemistry and Materials Science, The Weizmann Institute of Science Rehovot 76100 Israel
| | - David Milstein
- Department of Molecular Chemistry and Materials Science, The Weizmann Institute of Science Rehovot 76100 Israel
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Abstract
In photochemical production of hydrogen from water, the hole-mediated oxidation reaction is the rate-determining step. A poor solar-to-hydrogen efficiency is usually related to a mismatch between the internal quantum efficiency of photon-induced hole generation and the apparent quantum yield of hydrogen. This waste of photogenerated holes is unwanted yet unavoidable. Although great progress has been made, we are still far away from the required level of dexterity to deal with the associated challenges of wasted holes and its consequential chemical effects that have placed one of the greatest bottlenecks in attaining high solar-to-hydrogen efficiency. A critical assessment of the hole and its related phenomena in solar hydrogen production would, therefore, pave the way moving forward. In this regard, we focus on the contextual and conceptual understanding of the dynamics and kinetics of photogenerated holes and its critical role in driving redox reactions, with the objective of guiding future research. The main reasons behind and consequences of unused holes are examined and different approaches to improve overall efficiency are outlined. We also highlight yet unsolved research questions related to holes in solar fuel production.
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14
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Acceptorless Dehydrogenation of Primary Alcohols to Carboxylic Acids by Self-Supported NHC-Ru Single-Site Catalysts. J Catal 2022. [DOI: 10.1016/j.jcat.2022.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Si T, Kim HY, Oh K. One-Pot Direct Oxidation of Primary Amines to Carboxylic Acids through Tandem ortho-Naphthoquinone-Catalyzed and TBHP-Promoted Oxidation Sequence. Chemistry 2021; 27:18150-18155. [PMID: 34755925 DOI: 10.1002/chem.202103450] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Indexed: 12/11/2022]
Abstract
Biomimetic oxidation of primary amines to carboxylic acids has been developed where the copper-containing amine oxidase (CuAO)-like o-NQ-catalyzed aerobic oxidation was combined with the aldehyde dehydrogenase (ALDH)-like TBHP-mediated imine oxidation protocol. Notably, the current tandem oxidation strategy provides a new mechanistic insight into the imine intermediate and the seemingly simple TBHP-mediated oxidation pathways of imines. The developed metal-free amine oxidation protocol allows the use of molecular oxygen and TBHP, safe forms of oxidant that may appeal to the industrial application.
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Affiliation(s)
- Tengda Si
- Center for Metareceptome Research, Graduate School of Pharmaceutical Sciences, Chung-Ang University, 84 Heukseok-ro, Dongjak, Seoul, 06974, Republic of Korea
| | - Hun Young Kim
- Department of Global Innovative Drugs, Chung-Ang University, 84 Heukseok-ro, Dongjak, Seoul, 06974, Republic of Korea
| | - Kyungsoo Oh
- Center for Metareceptome Research, Graduate School of Pharmaceutical Sciences, Chung-Ang University, 84 Heukseok-ro, Dongjak, Seoul, 06974, Republic of Korea
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16
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A simple and efficient oxidation of primary and secondary benzylamines to acids using table salt in aqueous medium. Tetrahedron 2021. [DOI: 10.1016/j.tet.2021.132502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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17
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Luo J, Kar S, Rauch M, Montag M, Ben-David Y, Milstein D. Efficient Base-Free Aqueous Reforming of Methanol Homogeneously Catalyzed by Ruthenium Exhibiting a Remarkable Acceleration by Added Catalytic Thiol. J Am Chem Soc 2021; 143:17284-17291. [PMID: 34617436 PMCID: PMC8532156 DOI: 10.1021/jacs.1c09007] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Indexed: 12/11/2022]
Abstract
Production of H2 by methanol reforming is of particular interest due the low cost, ready availability, and high hydrogen content of methanol. However, most current methods either require very high temperatures and pressures or strongly rely on the utilization of large amounts of base. Here we report an efficient, base-free aqueous-phase reforming of methanol homogeneously catalyzed by an acridine-based ruthenium pincer complex, the activity of which was unexpectedly improved by a catalytic amount of a thiol additive. The reactivity of this system is enhanced by nearly 2 orders of magnitude upon addition of the thiol, and it can maintain activity for over 3 weeks, achieving a total H2 turnover number of over 130 000. On the basis of both experimental and computational studies, a mechanism is proposed which involves outer-sphere dehydrogenations promoted by a unique ruthenium complex with thiolate as an assisting ligand. The current system overcomes the need for added base in homogeneous methanol reforming and also highlights the unprecedented acceleration of catalytic activity of metal complexes achieved by the addition of a catalytic amount of thiol.
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Affiliation(s)
- Jie Luo
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot, 76100, Israel
| | - Sayan Kar
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot, 76100, Israel
| | - Michael Rauch
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot, 76100, Israel
| | - Michael Montag
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot, 76100, Israel
| | - Yehoshoa Ben-David
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot, 76100, Israel
| | - David Milstein
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot, 76100, Israel
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18
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Rauch M, Luo J, Avram L, Ben-David Y, Milstein D. Mechanistic Investigations of Ruthenium Catalyzed Dehydrogenative Thioester Synthesis and Thioester Hydrogenation. ACS Catal 2021; 11:2795-2807. [PMID: 33763290 PMCID: PMC7976608 DOI: 10.1021/acscatal.1c00418] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/03/2021] [Indexed: 12/12/2022]
Abstract
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We have recently reported the previously
unknown synthesis of thioesters
by coupling thiols and alcohols (or aldehydes) with liberation of
H2, as well as the reverse hydrogenation of thioesters,
catalyzed by a well-defined ruthenium acridine-9H based pincer complex.
These reactions are highly selective and are not deactivated by the
strongly coordinating thiols. Herein, the mechanism of this reversible
transformation is investigated in detail by a combined experimental
and computational (DFT) approach. We elucidate the likely pathway
of the reactions, and demonstrate experimentally how hydrogen gas
pressure governs selectivity toward hydrogenation or dehydrogenation.
With respect to the dehydrogenative process, we discuss a competing
mechanism for ester formation, which despite being thermodynamically
preferable, it is kinetically inhibited due to the relatively high
acidity of thiol compared to alcohol and, accordingly, the substantial
difference in the relative stabilities of a ruthenium thiolate intermediate
as opposed to a ruthenium alkoxide intermediate. Accordingly, various
additional reaction pathways were considered and are discussed herein,
including the dehydrogenative coupling of alcohol to ester and the
Tischenko reaction coupling aldehyde to ester. This study should inform
future green, (de)hydrogenative catalysis with thiols and other transformations
catalyzed by related ruthenium pincer complexes.
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Affiliation(s)
- Michael Rauch
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Jie Luo
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Liat Avram
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yehoshoa Ben-David
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - David Milstein
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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19
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Hu S, Feng H, Xi H, Meng Y, Li M, Huang L, Huang J. Copper-catalyzed deaminative alkynylation of secondary amines with alkynes: selectivity switch in the synthesis of diverse propargylamines. Org Chem Front 2021. [DOI: 10.1039/d1qo01240a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The copper-catalyzed selective deamination and alkynylation of the unsymmetrical secondary amines with terminal alkynes was reported with a broad substrate scope and excellent functional compatibility.
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Affiliation(s)
- Shengyun Hu
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China
- State Key Laboratory of New Drug and Pharmaceutical Process, Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry, Shanghai 201203, China
| | - Huangdi Feng
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China
- Shanghai Key Laboratory of Chemical Biology, East China University of Science and Technology, Shanghai 200237, China
| | - Hui Xi
- Key Laboratory of Tobacco Flavor Basic Research of CNTC, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450001, China
| | - Yuchen Meng
- State Key Laboratory of New Drug and Pharmaceutical Process, Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry, Shanghai 201203, China
| | - Ming Li
- State Key Laboratory of New Drug and Pharmaceutical Process, Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry, Shanghai 201203, China
| | - Liliang Huang
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China
| | - Junhai Huang
- State Key Laboratory of New Drug and Pharmaceutical Process, Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry, Shanghai 201203, China
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