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Chen L, Kang L, Cai D, Geng S, Liu Y, Chen J, Song S, Wang Y. Ultrafine Pt-based catalyst decorated with oxygenophilic Ni-sites accelerating alkaline H 2O dissociation for efficient hydrogen evolution. J Colloid Interface Sci 2023; 650:1715-1724. [PMID: 37499627 DOI: 10.1016/j.jcis.2023.07.119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/07/2023] [Accepted: 07/18/2023] [Indexed: 07/29/2023]
Abstract
Although Pt is a widely adopted commercial catalyst for the hydrogen evolution reaction (HER), its practical application is greatly limited by its prohibitive cost and high energy barrier for H2O dissociation in alkaline media. Herein, an ultrafine Pt-based catalyst decorated with oxygenophilic Ni-sites is rationally designed and successfully synthesized with Pt5(GS)10 (HGS = l-reduced glutathione) nanocluster precursor. The optimized Ni-decorated Pt catalyst (Ni-Pt-C-500) with ultrafine nanoparticles (about 1.6 nm) exhibits a low overpotential (14.0 mV) at 10 mA cm-2 and a mild Tafel slope of 20.8 mV dec-1 in the HER, which is superior to its undecorated counterpart (Pt-C-500), the commercial 20 wt% Pt/C catalyst and most of the previously reported Pt-based electrocatalysts. Experimental observations and theoretical calculations indicate that H2O could be spontaneously adsorbed to Ni-sites of the Ni-Pt-C-500 catalyst. Mechanistic studies reveal that Ni-sites promote HER by accelerating the kinetic of H2O cleavage and optimizing the electronic structure of Pt. This work paves a new avenue for designing other ultrafine hybrid electrocatalysts based on metal nanoclusters to enhance catalytic reaction kinetics.
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Affiliation(s)
- Liming Chen
- The Key Lab of Low-carbon Chemistry & Energy Conservation of Guangdong Province, PCMF Laboratory, School of Chemical Engineering and Technology, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Lianmei Kang
- The Key Lab of Low-carbon Chemistry & Energy Conservation of Guangdong Province, PCMF Laboratory, School of Chemical Engineering and Technology, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Dandan Cai
- The Key Lab of Low-carbon Chemistry & Energy Conservation of Guangdong Province, PCMF Laboratory, School of Chemical Engineering and Technology, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Shipeng Geng
- The Key Lab of Low-carbon Chemistry & Energy Conservation of Guangdong Province, PCMF Laboratory, School of Chemical Engineering and Technology, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Yangyang Liu
- The Key Lab of Low-carbon Chemistry & Energy Conservation of Guangdong Province, PCMF Laboratory, School of Chemical Engineering and Technology, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Jian Chen
- The Key Lab of Low-carbon Chemistry & Energy Conservation of Guangdong Province, PCMF Laboratory, School of Chemical Engineering and Technology, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Instrumental Analysis and Research Center, Sun Yat-sen University, Guangzhou 510275, China
| | - Shuqin Song
- The Key Lab of Low-carbon Chemistry & Energy Conservation of Guangdong Province, PCMF Laboratory, School of Chemical Engineering and Technology, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
| | - Yi Wang
- The Key Lab of Low-carbon Chemistry & Energy Conservation of Guangdong Province, PCMF Laboratory, School of Chemical Engineering and Technology, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
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Wu XX, Ma T, Qiao XX, Zou CP, Li G, He Y, Zhao XJ. Enantioselective Alkynylation of 2-Aryl-3H-indol-3-ones via Cooperative Catalysis of Copper/Chiral Phosphoric Acid. Chem Asian J 2023; 18:e202300526. [PMID: 37530657 DOI: 10.1002/asia.202300526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 08/03/2023]
Abstract
A facile enantioselective alkynylation of cyclic ketimines attached to a neutral functional group utilizing the dual Cu(I)-CPA catalysis is described. The strategy of the alkynylation of 2-aryl-3H-indol-3-one directly to chiral propargylic amines containing indolin-3-one moiety in good yields and enantioselectivities. Moreover, gram-scale synthesis of chiral propargylamines based C2-quaternary indolin-3-ones was performed. The synthetic applications were confirmed by transformations of the products with no decrease in the yield and enantioselectivity.
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Affiliation(s)
- Xi-Xi Wu
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
| | - Tao Ma
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
| | - Xiu-Xiu Qiao
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
| | - Chang-Peng Zou
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
| | - Ganpeng Li
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
| | - Yonghui He
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
| | - Xiao-Jing Zhao
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal Endophytes, State Ethnic Affairs Commission & Ministry of Education, School of Ethnic Medicine, Yunnan Minzu University, Kunming, 650500, China
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Kuroda Y, Park K, Shimazaki Y, Zhong RL, Sakaki S, Nakao Y. An Iridium/Aluminum Cooperative Strategy for the β-C(sp3)-H Borylation of Saturated Cyclic Amines. Angew Chem Int Ed Engl 2023; 62:e202300704. [PMID: 36988016 DOI: 10.1002/anie.202300704] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/28/2023] [Accepted: 03/28/2023] [Indexed: 03/30/2023]
Abstract
Despite the widespread success in the functionalization of C(sp2)-H bonds, the deliberate functionalization of C(sp3)-H bonds in a highly site- and stereoselective manner remains a longstanding challenge. Herein, we report an iridium/aluminum cooperative catalyst system that enables the β-selective C-H borylation of saturated cyclic amines and lactams. Furthermore, we have accomplished an enantioselective variant using binaphthol-derived chiral aluminum catalysts to forge C-B bonds with high levels of stereocontrol. Computational studies suggest that the formation of a Lewis pair with the substrates is crucial to lower the energy of the transition state for the rate-determining reductive elimination step.
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Affiliation(s)
- Yusuke Kuroda
- Kyoto University: Kyoto Daigaku, Material Chemistry, JAPAN
| | - Kyungho Park
- Kyoto University: Kyoto Daigaku, Material Chemistry, JAPAN
| | - Yuto Shimazaki
- Kyoto University: Kyoto Daigaku, Material Chemistry, JAPAN
| | - Rong-Lin Zhong
- Kyoto University: Kyoto Daigaku, Fukui Institute for Fundamental Chemistry, JAPAN
| | - Shigeyoshi Sakaki
- Kyoto University: Kyoto Daigaku, Fukui Institute for Fundamental Chemistry, JAPAN
| | - Yoshiaki Nakao
- Kyoto University, Department of Material Chemistry, Katsura, 615-8510, Kyoto, JAPAN
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Chen Z, Li J, Wang S, Zhao J, Liu J, Shen J, Qi C, Yang P. Structure-property-performance relationship of transition metal doped WO 3 mixed oxides for catalytic degradation of organic pollutants. Chemosphere 2023; 316:137797. [PMID: 36634713 DOI: 10.1016/j.chemosphere.2023.137797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/18/2022] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Abstract
Transition metal doped WO3 mixed oxides (named as W-M-O, M = Nb, Fe, Cr, Cu, Ti or Sn, respectively) with high structure stability were synthesized by modified sol-gel method using citric acid as organic crosslinking agent, and were evaluated for catalytic elimination of low-concentration toluene, monochlorobenzene and 1,2-dichloroethance with high toxicity and relatively stable molecule structure, as the typical examples for the pollutants of various volatile organic compounds (VOCs). Results of the structure-property-performance relationship research showed that mesoporous structure and nanocrystalline/amorphous state were formed, and binary metal components were dispersed into each other, which contributed to promoting the metal/metal electron interaction and adjusting the physicochemical properties of mixed metal oxides. The sequence of apparent catalytic activity for toluene degradation was: W-Nb-O>W-Fe-O>W-Cr-O, W-Cu-O>W-Ti-O>W-Sn-O>WO3, and the sequence for monochlorobenzene degradation was: W-Nb-O>W-Fe-O>W-Cr-O, W-Ti-O>W-Cu-O>W-Sn-O>WO3. There existed cooperative catalytic effect: mesopore and surface acid sites of catalysts facilitated adsorption, activation and breakage of the C-X bond, and then redox sites of catalysts promoted deep oxidation of a series of reaction intermediates to transform into CO2 and H2O. Especially, the optimized W-Nb-O catalyst deserved more attention, since it represented remarkable catalytic activity, selectivity and durability for three typical VOCs degradation along with good resistance to water vapor and corrosion of HCl.
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Affiliation(s)
- Zhenyang Chen
- Zhejiang Key Laboratory of Alternative Technologies for Fine Chemicals Process, School of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Jing Li
- Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, 252059, China
| | - Songlin Wang
- School of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang, Henan, 453003, China
| | - Junhu Zhao
- School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, 430070, China
| | - Jiang Liu
- Zhejiang Key Laboratory of Alternative Technologies for Fine Chemicals Process, School of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Junhao Shen
- Zhejiang Key Laboratory of Alternative Technologies for Fine Chemicals Process, School of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Chenze Qi
- Zhejiang Key Laboratory of Alternative Technologies for Fine Chemicals Process, School of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China
| | - Peng Yang
- Zhejiang Key Laboratory of Alternative Technologies for Fine Chemicals Process, School of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, 312000, China.
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Chen XC, Yao YQ, Zhao KC, Liu L, Lu Y, Liu Y. Cooperative Catalysis of Ru(III)-Porphyrin in CO 2 -Involved Synthesis of Oxazolidinones. Chem Asian J 2021; 16:2504-2510. [PMID: 34258877 DOI: 10.1002/asia.202100533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/08/2021] [Indexed: 01/09/2023]
Abstract
CO2 -transformations into high value-added products have become a fascinating area in green chemistry. Herein, a Ru(III)-porphyrin catalyst (RuCl3 ⋅ 3H2 O-H2 TPP) was found highly efficient in the three-component reaction of CO2 , aliphatic amines and dichloroethane (or its derivative) for synthesis of oxazolidinones in the yields of 71∼91%. It was indicated by means of the control experiments and UV-vis spectra that CO2 was stoichiometrically activated by the involved aliphatic amine substrates to form a stable carbamate salt while 1,2-dichloroethane (or its derivative) was independently activated by the involved Ru(III)-porphyrin catalyst. The combination of CO2 -activation by aliphatic amines with 1,2-dichloroethane activation by Ru(III)-porphyrin catalyst cooperatively contributed to this successful transformation.
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Affiliation(s)
- Xiao-Chao Chen
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, P. R. China
| | - Yin-Qing Yao
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, P. R. China
| | - Kai-Chun Zhao
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, P. R. China
| | - Lei Liu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, P. R. China
| | - Yong Lu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, P. R. China
| | - Ye Liu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, P. R. China
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Knox GJ, Hutchings-Goetz LS, Pearson CM, Snaddon TN. Tertiary Amine Lewis Base Catalysis in Combination with Transition Metal Catalysis. Top Curr Chem (Cham) 2020; 378:16. [PMID: 31942682 DOI: 10.1007/s41061-020-0279-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 01/02/2020] [Indexed: 01/03/2023]
Abstract
The cooperation between two orthogonal catalytic events during the formation of carbon-carbon and carbon-heteroatom bonds has emerged as an effective strategy for enantioselective chemical synthesis. In recent years, a number of pioneering investigations have described useful chemical synthesis methods whereby the reactivity or nucleophile-electrophile combinations can be fine-tuned or extended far beyond the effect and influence of a single catalyst. The recognition of this has had profound implications for the development cooperative catalysis as a field and has provided a foundation for the development of broadly useful chemical synthesis methods. This chapter focuses on the combination of tertiary amine Lewis base and transition metal catalysts, which the authors hope will simulate further developments and advances.
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Affiliation(s)
- Gary J Knox
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - Luke S Hutchings-Goetz
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - Colin M Pearson
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - Thomas N Snaddon
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN, 47405, USA.
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7
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Lu X, Jiang Z, Yuan X, Wu Y, Malpass-Evans R, Zhong Y, Liang Y, McKeown NB, Wang H. A bio-inspired O 2-tolerant catalytic CO 2 reduction electrode. Sci Bull (Beijing) 2019; 64:1890-1895. [PMID: 36659584 DOI: 10.1016/j.scib.2019.04.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 03/12/2019] [Accepted: 03/12/2019] [Indexed: 01/21/2023]
Abstract
The electrochemical reduction of CO2 to give CO in the presence of O2 would allow the direct valorization of flue gases from fossil fuel combustion and of CO2 captured from air. However, it is a challenging task because O2 reduction is thermodynamically favored over that of CO2. 5% O2 in CO2 near catalyst surface is sufficient to completely inhibit the CO2 reduction reaction. Here we report an O2-tolerant catalytic CO2 reduction electrode inspired by part of the natural photosynthesis unit. The electrode comprises of heterogenized cobalt phthalocyanine molecules serving as the cathode catalyst with >95% Faradaic efficiency (FE) for CO2 reduction to CO coated with a polymer of intrinsic microporosity that works as a CO2-selective layer with a CO2/O2 selectivity of ∼20. Integrated into a flow electrolytic cell, the hybrid electrode operating with a CO2 feed gas containing 5% O2 exhibits a FECO of 75.9% with a total current density of 27.3 mA/cm2 at a cell voltage of 3.1 V. A FECO of 49.7% can be retained when the O2 fraction increases to 20%. Stable operation for 18 h is demonstrated. The electrochemical performance and O2 tolerance can be further enhanced by introducing cyano and nitro substituents to the phthalocyanine ligand.
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Affiliation(s)
- Xu Lu
- Department of Chemistry, Yale University, New Haven, CT 06520, USA; Energy Sciences Institute, Yale University, West Haven, CT 06516, USA
| | - Zhan Jiang
- Department of Materials Science and Engineering, Shenzhen Key Laboratory of Printed Organic Electronics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xiaolei Yuan
- Department of Chemistry, Yale University, New Haven, CT 06520, USA; Energy Sciences Institute, Yale University, West Haven, CT 06516, USA; Institute of Functional Nano and Soft Materials, Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, China
| | - Yueshen Wu
- Department of Chemistry, Yale University, New Haven, CT 06520, USA; Energy Sciences Institute, Yale University, West Haven, CT 06516, USA
| | | | - Yiren Zhong
- Department of Chemistry, Yale University, New Haven, CT 06520, USA; Energy Sciences Institute, Yale University, West Haven, CT 06516, USA
| | - Yongye Liang
- Department of Materials Science and Engineering, Shenzhen Key Laboratory of Printed Organic Electronics, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Neil B McKeown
- EastChem, School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, UK.
| | - Hailiang Wang
- Department of Chemistry, Yale University, New Haven, CT 06520, USA; Energy Sciences Institute, Yale University, West Haven, CT 06516, USA.
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Abstract
An efficient deuteration process of α-C-H bonds in various carbonyl-based pharmaceutical compounds has been developed. Catalytic reactions are initiated by the action of Lewis acidic B(C6F5)3 and D2O, converting a drug molecule into the corresponding boron-enolate. Ensuing deuteration of the enolate by in situ-generated D2O+-H then results in the formation of α-deuterated bioactive carbonyl compounds with up to >98% deuterium incorporation.
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Affiliation(s)
- Yejin Chang
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Tanner Myers
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Masayuki Wasa
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States
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9
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Verhoeven DGA, Kwakernaak J, van Wiggen MAC, Lutz M, Moret M. Cobalt(II) and (I) Complexes of Diphosphine-Ketone Ligands: Catalytic Activity in Hydrosilylation Reactions. Eur J Inorg Chem 2019; 2019:660-667. [PMID: 31007578 PMCID: PMC6472597 DOI: 10.1002/ejic.201801221] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Indexed: 12/21/2022]
Abstract
The hydrosilylation of unsaturated compounds homogeneously catalyzed by cobalt complexes has gained considerable attention in the last years, aiming at substituting precious metal-based catalysts. In this study, the catalytic activity of well-characterized CoII and CoI complexes of the pToldpbp ligand is demonstrated in the hydrosilylation of 1-octene with phenylsilane. The CoI complex is the better precatalyst for the mentioned reaction under mild conditions, at 1 mol-% catalyst, 1 h, room temperature, and without solvent, yielding 84 % of octylphenylsilane. Investigation of the substrate scope shows lower performance of the catalyst in styrene hydrosilylation, but excellent results with allylbenzene (84 %) and acetophenone (> 99 %). This catalytic study contributes to the field of cobalt-catalyzed hydrosilylation reactions and shows the first example of catalysis employing the dpbp ligand in combination with a base metal.
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Affiliation(s)
- Dide G. A. Verhoeven
- Organic Chemistry & CatalysisDebye Institute for Nanomaterials ScienceFaculty of ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Joost Kwakernaak
- Organic Chemistry & CatalysisDebye Institute for Nanomaterials ScienceFaculty of ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Maxime A. C. van Wiggen
- Organic Chemistry & CatalysisDebye Institute for Nanomaterials ScienceFaculty of ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Martin Lutz
- Crystal and Structural ChemistryBijvoet Center for Biomolecular ResearchUtrecht UniversityPadualaan 83584 CHUtrechtThe Netherlands
| | - Marc‐Etienne Moret
- Organic Chemistry & CatalysisDebye Institute for Nanomaterials ScienceFaculty of ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
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Fyfe JWB, Kabia OM, Pearson CM, Snaddon TN. Si-Directed regiocontrol in asymmetric Pd-catalyzed allylic alkylations using C1-ammonium enolate nucleophiles. Tetrahedron 2018; 74:5383-5391. [PMID: 30559533 DOI: 10.1016/j.tet.2018.04.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cooperative catalysis enables the direct enantioselective α-allylation of linear prochiral esters using Si-substituted allyl electrophiles. The Si-substituent directs the regioselectivity of enantioselective bond formation and provides products containing synthetically versatile pentafluorophenyl ester and vinylsilane moieties. Critical to the efficacy of this process was the recognition that the ancillary ligand on palladium could be altered to prevent formation of a deleterious ether by-product, whilst retaining enantioselectivity through the Lewis base catalyst. Flexibility such as this is unique to cooperative catalysis events and provides efficient access to an array of enantioenriched products that are orthogonally functionalized and easily modified.
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Affiliation(s)
- James W B Fyfe
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, Indiana 47405, United States
| | - Omaru M Kabia
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, Indiana 47405, United States
| | - Colin M Pearson
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, Indiana 47405, United States
| | - Thomas N Snaddon
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, Indiana 47405, United States
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11
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Abstract
Double-label crossover, modified-substrate, and catalyst comparison experiments in the gold and palladium dual-catalytic rearrangement/cross-coupling of allenoates were performed in order to probe the mechanism of this reaction. The results are consistent with a cooperative catalysis mechanism whereby 1) gold activates the substrate prior to oxidative addition by palladium, 2) gold acts as a carbophilic rather than oxophilic Lewis acid, 3) competing olefin isomerization is avoided, 4) gold participates beyond the first turnover and therefore does not serve simply to generate the active palladium catalyst, and 5) single-electron transfer is not involved. These experiments further demonstrate that the cooperativity of both gold and palladium in the reaction is essential because significantly lower to zero conversion is achieved with either metal alone in comparison studies that examined multiple potential gold, palladium, and silver catalysts and precatalysts. Notably, employment of the optimized cocatalysts, PPh3AuOTf and Pd2dba3, separately (i.e., only Au or only Pd) results in zero conversion to product at all monitored time points compared to quantitative conversion to product when both are present in cocatalytic reactions.
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Affiliation(s)
- Mohammad Al-Amin
- Department of Chemistry, University of California at Irvine, Irvine, CA 92697-2025, USA
| | - Katrina E. Roth
- Department of Chemistry, University of California at Irvine, Irvine, CA 92697-2025, USA
| | - Suzanne A. Blum
- Department of Chemistry, University of California at Irvine, Irvine, CA 92697-2025, USA
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