1
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Chen J, Wei WT, Li Z, Lu Z. Metal-catalyzed Markovnikov-type selective hydrofunctionalization of terminal alkynes. Chem Soc Rev 2024; 53:7566-7589. [PMID: 38904176 DOI: 10.1039/d4cs00167b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Metal-catalyzed highly Markovnikov-type selective hydrofunctionalization of terminal alkynes provides a straightforward and atom-economical route to access 1,1-disubstituted alkenes, which have a wide range of applications in organic synthesis. However, the highly Markovnikov-type selective transformations are challenging due to the electronic and steric effects during the addition process. With the development of metal-catalyzed organic synthesis, different metal catalysts have been developed to solve this challenge, especially for platinum group metal catalysts. In this perspective, we review homogeneous metal-catalyzed Markovnikov-type selective hydrofunctionalization of terminal alkynes according to the classified element types as well as reaction mechanisms. Future avenues for investigation are also presented to help expand this exciting field.
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Affiliation(s)
- Jieping Chen
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310058, China.
| | - Wen-Ting Wei
- School of Materials Science and Chemical Engineering, Ningbo University, Zhejiang, 315211, China
| | - Zhuocheng Li
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310058, China.
| | - Zhan Lu
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310058, China.
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2
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Meher NK, Suryavansi M, Geetharani K. Regioselective Hydroboration of Unsymmetrical Internal Alkynes Catalyzed by a Cobalt Pincer-NHC Complex. Org Lett 2024; 26:5862-5867. [PMID: 38935048 DOI: 10.1021/acs.orglett.4c02216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2024]
Abstract
Highly regioselective hydroboration of unsymmetrical internal alkynes remains a significant challenge for synthesizing valuable alkenylboronate esters. Herein, we describe an easily synthesizable pincer NHC-based Co complex as a catalyst for the cis-α selective hydroboration of unactivated internal alkynes and the cis-β selective hydroboration of activated internal alkynes with pinacolborane. The reaction showcases high chemo-, regio-, and stereoselectivity, and the catalyst displays high efficiency and very low loading under base-free reaction conditions. The reaction scope was demonstrated by alkynes having a variety of functional groups. The mechanistic studies suggest a feasible Co-boryl intermediate to explain the unusual regioselectivity.
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Affiliation(s)
- Naresh Kumar Meher
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Maruti Suryavansi
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - K Geetharani
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
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3
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Li Z, Zhao J, Xue W, Tang J, Li S, Ge Y, Xu J, Zheng X, Li R, Chen H, Fu H. Efficient and selective external activator-free cobalt catalyst for hydroboration of terminal alkynes enabled by BiPyPhos. Org Biomol Chem 2024; 22:4455-4460. [PMID: 38764306 DOI: 10.1039/d4ob00435c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2024]
Abstract
Herein, a robust catalyst system, composed of a bipyridine-based diphosphine ligand (BiPyPhos) and a cobalt precursor Co(acac)2, is successfully developed and applied in the hydroboration of terminal alkynes, exclusively affording various versatile β-E-vinylboronates in high yields at room temperature.
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Affiliation(s)
- Zheng Li
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
| | - Jiangui Zhao
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
| | - Weichao Xue
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
| | - Juan Tang
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
| | - Shun Li
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
| | - Yicen Ge
- College of Materials, Chemistry and Chemical Engineering, Chengdu University of Technology, Chengdu, Sichuan 610059, China
| | - Jiaqi Xu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
| | - Xueli Zheng
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
| | - Ruixiang Li
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
| | - Hua Chen
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
| | - Haiyan Fu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
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4
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Tian L, Song X, Liu Y, Zhang C, Shi L, Chen Q, Deng Y, Cui W, Shan S, Hu T. Defect-engineering improves the activity of Metal-Organic frameworks for catalyzing hydroboration of Alkynes: A combination of experimental investigation and Density functional theory calculations. J Colloid Interface Sci 2024; 662:263-275. [PMID: 38354554 DOI: 10.1016/j.jcis.2024.02.067] [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: 12/08/2023] [Revised: 02/05/2024] [Accepted: 02/06/2024] [Indexed: 02/16/2024]
Abstract
Defect-engineered metal-organic frameworks (DEMOFs) are emerging advanced materials. The construction of DEMOFs is of great significance; however, DEMOF-based catalysis remains unexplored. (E)-vinylboronates, an important building block for asymmetric synthesis, can be synthesized via the hydroboration of alkynes. However, the lack of high-performance catalysts considerably hinders their synthesis. Herein, a series of DEHKUST-1 (HKUST = Hong Kong University of Science and Technology) (Da-f) catalysts with missing occupation of linkers at Cu nodes were designed by partially replacing benzene-1,3,5-tricarboxylate (H3BTC) with defective connectors of pyridine-3,5-dicarboxylate (PYDC) to efficiently promote the hydroboration of alkynes. Results showed that the Dd containing 0.8 doping ratio of PYDC exhibited remarkable catalytic activity than the defect-free HKUST-1. This originated from the improved accessibility for reactants towards the Lewis acid active Cu sites of DEHKUST-1 due to the presence of plenty of rooms next to the Cu sites and enhanced coordination ability in such 'defective' HKUST-1. Dd had high selectivity (>99 %) and yield (>96 %) for (E)-vinylboronates and extensive functional group compatibility for terminal alkynes. Density functional theory (DFT) calculations were performed to elucidate the mechanism of hydroboration. Compared with that of defect-free HKUST-1, the low energy barrier of DEHKUST-1 can be attributed to the lower coordination number of Cu sites and enhanced accessibility of Cu active sites towards reagents.
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Affiliation(s)
- Long Tian
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Xiaonan Song
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Yi Liu
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Churu Zhang
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Lan Shi
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Qinglin Chen
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Yanyan Deng
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Weigang Cui
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, PR China
| | - Shaoyun Shan
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, PR China.
| | - Tianding Hu
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, PR China.
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5
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Duran Arroyo V, Arevalo R. Tandem manganese catalysis for the chemo-, regio-, and stereoselective hydroboration of terminal alkynes: in situ precatalyst activation as a key to enhanced chemoselectivity. RSC Adv 2024; 14:5514-5523. [PMID: 38352676 PMCID: PMC10863604 DOI: 10.1039/d3ra08747f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/05/2024] [Indexed: 02/16/2024] Open
Abstract
The manganese(ii) complex [Mn(iPrPNP)Cl2] (iPrPNP = 2,6-bis(diisopropylphosphinomethyl)pyridine) was found to catalyze the stereo- and regioselective hydroboration of terminal alkynes employing HBPin (pinacolborane). In the absence of in situ activators, mixtures of alkynylboronate and E-alkenylboronate esters were formed, whereas when NaHBEt3 was employed as the in situ activator, E-alkenylboronate esters were exclusively accessed. Mechanistic studies revealed a tandem C-H borylation/semihydrogenation pathway accounting for the formation of the products. Stoichiometric reactions hint toward reaction of a Mn-H active species with the terminal alkyne as the catalyst entry pathway to the cycle, whereas reaction with HBPin led to catalyst deactivation.
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Affiliation(s)
- Victor Duran Arroyo
- Department of Chemistry and Biochemistry, University of California 5200 North Lake Road 95343 Merced California USA
| | - Rebeca Arevalo
- Department of Chemistry and Biochemistry, University of California 5200 North Lake Road 95343 Merced California USA
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Lee B, Pabst TP, Hierlmeier G, Chirik PJ. Exploring the Effect of Pincer Rigidity on Oxidative Addition Reactions with Cobalt(I) Complexes. Organometallics 2023; 42:708-718. [PMID: 37223209 PMCID: PMC10201995 DOI: 10.1021/acs.organomet.3c00079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
Cobalt complexes containing the 2,6-diaminopyridine-substituted PNP pincer (iPrPNMeNP = 2,6-(iPr2PNMe)2(C5H3N)) were synthesized. A combination of solid-state structures and investigation of the cobalt(I)/(II) redox potential established a relatively rigid and electron-donating chelating ligand as compared to iPrPNP (iPrPNP = 2,6-(iPr2PCH2)2(C5H3N)). Based on a buried volume analysis, the two pincer ligands are sterically indistinguishable. Nearly planar, diamagnetic, four-coordinate complexes were observed independent of the field strength (chloride, alkyl, aryl) of the fourth ligand completing the coordination sphere of the metal. Computational studies supported a higher barrier for C-H oxidative addition, largely a result of the increased rigidity of the pincer. The increased oxidative addition barrier resulted in stabilization of (iPrPNMeNP)Co(I) complexes, enabling the characterization of the cobalt boryl and the cobalt hydride dimer by X-ray crystallography. Moreover, (iPrPNMeNP)CoMe served as an efficient precatalyst for alkene hydroboration likely because of the reduced propensity to undergo oxidative addition, demonstrating that reactivity and catalytic performance can be tuned by rigidity of pincer ligands.
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Affiliation(s)
- Boran Lee
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Tyler P Pabst
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Gabriele Hierlmeier
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Paul J Chirik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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7
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Fürstner A. How to Break the Law:
trans
‐Hydroboration and
gem
‐Hydroboration of Alkynes. Isr J Chem 2023. [DOI: 10.1002/ijch.202300004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Affiliation(s)
- Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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8
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Gregori BJ, Schmotz MWS, Jacobi von Wangelin A. Stereoselective Semi-Hydrogenations of Alkynes by First-Row (3d) Transition Metal Catalysts. ChemCatChem 2022; 14:e202200886. [PMID: 36632425 PMCID: PMC9825939 DOI: 10.1002/cctc.202200886] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/25/2022] [Indexed: 01/14/2023]
Abstract
The chemo- and stereoselective semi-hydrogenation of alkynes to alkenes is a fundamental transformation in synthetic chemistry, for which the use of precious 4d or 5d metal catalysts is well-established. In mankind's unwavering quest for sustainability, research focus has considerably veered towards the 3d metals. Given their high abundancy and availability as well as lower toxicity and noxiousness, they are undoubtedly attractive from both an economic and an environmental perspective. Herein, we wish to present noteworthy and groundbreaking examples for the use of 3d metal catalysts for diastereoselective alkyne semi-hydrogenation as we embark on a journey through the first-row transition metals.
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Affiliation(s)
- Bernhard J. Gregori
- Dept. of ChemistryUniversity of HamburgMartin Luther King Pl 620146HamburgGermany
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9
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Qiu H, Lv K, Qu H, Zhang X, Yuan T, Yao W, Xue F, Ma M. Chemoselective electrocatalytic hydroboration of alkynes with pinacolborane. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Zhang Y, Li X, Mo Q, Shi W, Zhao J, Zhu S. Highly Regioselective Cobalt‐Catalyzed Hydroboration of Internal Alkynes. Angew Chem Int Ed Engl 2022; 61:e202208473. [DOI: 10.1002/anie.202208473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Indexed: 12/18/2022]
Affiliation(s)
- Yan‐Dong Zhang
- Frontiers Science Center for New Organic Matter, the State Key Laboratory and Institute of Elemento-Organic Chemistry College of Chemistry Nankai University Tianjin 300071 China
| | - Xiao‐Yu Li
- Frontiers Science Center for New Organic Matter, the State Key Laboratory and Institute of Elemento-Organic Chemistry College of Chemistry Nankai University Tianjin 300071 China
| | - Qian‐Kun Mo
- Frontiers Science Center for New Organic Matter, the State Key Laboratory and Institute of Elemento-Organic Chemistry College of Chemistry Nankai University Tianjin 300071 China
| | - Wen‐Bin Shi
- Frontiers Science Center for New Organic Matter, the State Key Laboratory and Institute of Elemento-Organic Chemistry College of Chemistry Nankai University Tianjin 300071 China
| | - Jia‐Bao Zhao
- Frontiers Science Center for New Organic Matter, the State Key Laboratory and Institute of Elemento-Organic Chemistry College of Chemistry Nankai University Tianjin 300071 China
| | - Shou‐Fei Zhu
- Frontiers Science Center for New Organic Matter, the State Key Laboratory and Institute of Elemento-Organic Chemistry College of Chemistry Nankai University Tianjin 300071 China
- Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192 China
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11
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Hidalgo N, Moreno JJ, García‐Rubio I, Campos J. Enhanced Dihydrogen Activation by Mononuclear Iridium(II) Compounds: A Mechanistic Study. Angew Chem Int Ed Engl 2022; 61:e202206831. [PMID: 35737594 PMCID: PMC9545596 DOI: 10.1002/anie.202206831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Nereida Hidalgo
- Instituto de Investigaciones Químicas (IIQ) Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA) Consejo Superior de Investigaciones Científicas (CSIC) Universidad de Sevilla Avenida Américo Vespucio 49 41092 Sevilla Spain
| | - Juan José Moreno
- Instituto de Investigaciones Químicas (IIQ) Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA) Consejo Superior de Investigaciones Científicas (CSIC) Universidad de Sevilla Avenida Américo Vespucio 49 41092 Sevilla Spain
| | - Inés García‐Rubio
- Centro Universitario de la Defensa Ctra de Huesca s/n 50090 Zaragoza Spain
- Department of Condensed Matter Physics Faculty of Sciences University of Zaragoza Calle Pedro Cerbuna 50009 Zaragoza Spain
| | - Jesús Campos
- Instituto de Investigaciones Químicas (IIQ) Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA) Consejo Superior de Investigaciones Científicas (CSIC) Universidad de Sevilla Avenida Américo Vespucio 49 41092 Sevilla Spain
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12
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Chen J, Ying J, Lu Z. Cobalt-catalyzed branched selective hydroallylation of terminal alkynes. Nat Commun 2022; 13:4518. [PMID: 35922446 PMCID: PMC9349270 DOI: 10.1038/s41467-022-32291-3] [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: 04/13/2022] [Accepted: 07/21/2022] [Indexed: 11/28/2022] Open
Abstract
Here, we reported a cobalt-hydride-catalyzed Markovnikov-type hydroallylation of terminal alkynes with allylic electrophile to access valuable and branched skipped dienes (1,4-dienes) with good regioselectivity. This operationally simple protocol exhibits excellent functional group tolerance and exceptional substrate scope. The reactions could be carried out in gram-scale with TON (turn over number) up to 1160, and the products could be easily derivatized. The preliminary mechanism of electrophilic allylation of α-selective cobalt alkenyl intermediate was proposed based on deuterium labeling experiment and kinetic studies. Selectively generating “skipped” dienes, where two carbon–carbon double bonds are separated by a saturated carbon center, is an interesting problem in organic chemistry, with few reliable, catalytic methods currently available. Here, the authors report branched selective hydroallylation of terminal alkynes with allylic bromides to form skipped dienes, via cobalt catalysis.
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Affiliation(s)
- Jieping Chen
- Center of chemistry for Frontier Technologies, Department of Chemistry, Zhejiang University, Hangzhou, 310058, China
| | - Jiale Ying
- Center of chemistry for Frontier Technologies, Department of Chemistry, Zhejiang University, Hangzhou, 310058, China
| | - Zhan Lu
- Center of chemistry for Frontier Technologies, Department of Chemistry, Zhejiang University, Hangzhou, 310058, China. .,College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China.
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13
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Zhang YD, Li XY, Mo QK, Shi WB, Zhao JB, Zhu SF. Highly Regioselective Cobalt‐Catalyzed Hydroboration of Internal Alkynes. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202208473] [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)
| | - Xiao-Yu Li
- Nankai University College of Chemistry CHINA
| | - Qian-Kun Mo
- Nankai University College of Chemistry CHINA
| | - Wen-Bin Shi
- Nankai University College of Chemistry CHINA
| | | | - Shou-Fei Zhu
- Nankai University Sate Key Laboratory and Institute of Elemento-Organic Chemistry 94 Wijin Road 300071 Tianjin CHINA
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14
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Narro AL, Arman HD, Tonzetich ZJ. Mechanistic Studies of Alkyne Hydroboration by a Well-Defined Iron Pincer Complex: Direct Comparison of Metal-Hydride and Metal-Boryl Reactivity. Inorg Chem 2022; 61:10477-10485. [PMID: 35766905 DOI: 10.1021/acs.inorgchem.2c01325] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Iron-hydride and iron-boryl complexes supported by a pyrrole-based pincer ligand, tBuPNP (PNP = anion of 2,5-bis(di-tert-butylphosphinomethyl)pyrrole), were employed for a detailed mechanistic study on the hydroboration of internal alkynes. Several novel complexes were isolated and fully characterized, including iron-vinyl and iron-boryl species, which represent likely intermediates in the catalytic hydroboration pathway. In addition, the products of alkyne insertion into the Fe-B bond have been isolated and structurally characterized. Mechanistic studies of the hydroboration reaction favor a pathway involving an active iron-hydride species, [FeH(tBuPNP)], which readily inserts alkyne and undergoes subsequent reaction with hydroborane to generate product. The iron-boryl species, [Fe(BR2)(tBuPNP)] (R2 = pin or cat), was found to be chemically competent, although its use in catalysis entailed an induction period whereby the iron-hydride species was generated. Stoichiometric reactions and kinetic experiments were performed to paint a fuller picture of the mechanism of alkyne hydroboration, including pathways for catalyst deactivation and the influence of substrate bulk on catalytic efficacy.
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Affiliation(s)
- Ana L Narro
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Hadi D Arman
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Zachary J Tonzetich
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
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15
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Altarejos J, Valero A, Manzano R, Carreras J. Synthesis of Tri‐ and Tetrasubstituted Alkenyl Boronates from Alkynes. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Julia Altarejos
- Universidad de Alcalá Facultad de Ciencias: Universidad de Alcala Facultad de Ciencias Química Orgánica y Química Inorgánica SPAIN
| | - Antonio Valero
- Universidad de Alcalá Facultad de Ciencias: Universidad de Alcala Facultad de Ciencias Química Orgánica y Química Inorgánica SPAIN
| | - Rubén Manzano
- Universidad de Alcalá Facultad de Ciencias: Universidad de Alcala Facultad de Ciencias Química Orgánica y Química Inorgánica SPAIN
| | - Javier Carreras
- Universidad de Alcalá Facultad de Ciencias: Universidad de Alcala Facultad de Ciencias Química Orgánica y Química Inorgánica Carretera Madrid-Barcelona km 33,6, Campus Universitario.Facultad de Farmacia 28805 Alcalá de Henares SPAIN
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16
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Hidalgo N, Moreno JJ, Garcia-Rubio I, Campos J. Enhanced Dihydrogen Activation by Mononuclear Iridium(II) Compounds: A Mechanistic Study. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202206831] [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)
- Nereida Hidalgo
- CSIC: Consejo Superior de Investigaciones Cientificas IIQ SPAIN
| | - Juan J Moreno
- CSIC: Consejo Superior de Investigaciones Cientificas IIQ SPAIN
| | - Ines Garcia-Rubio
- Universidad de Zaragoza Department of Condensed Matter Physics SPAIN
| | - Jesus Campos
- Consejo Superior de Investigaciones Cientificas Institute of Chemical Research Av. Americo Vespucio 49, Isla de la 41092 Sevilla SPAIN
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17
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Recent advances in the boration and cyanation functionalization of alkenes and alkynes. JOURNAL OF SAUDI CHEMICAL SOCIETY 2022. [DOI: 10.1016/j.jscs.2022.101483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Ott JC, Bürgy D, Guan H, Gade LH. 3d Metal Complexes in T-shaped Geometry as a Gateway to Metalloradical Reactivity. Acc Chem Res 2022; 55:857-868. [PMID: 35164502 DOI: 10.1021/acs.accounts.1c00737] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
ConspectusLow-valent, low-coordinate 3d metal complexes represent a class of extraordinarily reactive compounds that can act as reagents and catalysts for challenging bond-activation reactions. The pursuit of these electron-deficient metal complexes in low oxidation states demands ancillary ligands capable of providing not only energetic stabilization but also sufficiently high steric bulk at the metal center. From this perspective, pincer ligands are particularly advantageous, as their prearranged, meridional coordination mode scaffolds the active center while the substituents of the peripheral donor atoms provide effective steric shielding for the coordination sphere. In a T-shaped geometry, the transition metal complexes possess a precisely defined vacant coordination site, which, combined with the often observed high-spin electron configuration, exhibits unusually high selectivity of these compounds with respect to one-electron redox chemistry. In light of the intractable reaction pathways typically observed with related electronically unsaturated 3d transition metal complexes, the pincer coordination mode enables the isolation of low-valent compounds with more controlled and unique reactivity. We have thus investigated a series of T-shaped metal(I) complexes using three different types of pincer ligands, which may be regarded as "metalloradicals" due to their selectively exposed unpaired electrons.These compounds display remarkably high thermal stability and represent rarely observed "naked" monovalent metal species featuring both monomeric and dimeric structures. Extensive reactivity studies using various organic substrates highlight a strong tendency of these paramagnetic compounds to undergo one-electron oxidation, leading to the isolation of a plethora of metal(II) species with reduced organic ligands as unusual structural elements. The exploration of C2 symmetric T-shaped Ni(I) complexes as asymmetric catalysts also shows success in enantioselective hydrodehalogenation of geminal dihalogenides. In addition, this specific class of low-valent, low-coordinate complexes can be further diversified by introducing redox-active pincer ligands or building homobimetallic systems with two T-shaped units.This Account focuses on the discussion of selected examples of iron, cobalt, and nickel pincer complexes bearing a [P,N,P] or [N,N,N] donor set; however, their electronic structure and radical-type reactivity can be broadly extended to other pincer systems. The availability of various types of pincer ligands should allow fine-tuning of the reactivity of the T-shaped complexes. Given the unprecedented reactivity observed with these compounds, we expect the studies of T-shaped 3d metal complexes to be a fertile field for advancing base metal catalysis.
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Affiliation(s)
- Jonas C. Ott
- Anorganisch-Chemisches Institut, Universität Heidelberg, 69120 Heidelberg, Germany
| | - David Bürgy
- Anorganisch-Chemisches Institut, Universität Heidelberg, 69120 Heidelberg, Germany
| | - Hairong Guan
- Department of Chemistry, University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221-0172, United States
| | - Lutz H. Gade
- Anorganisch-Chemisches Institut, Universität Heidelberg, 69120 Heidelberg, Germany
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19
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Stefanowska K, Sokolnicki T, Walkowiak J, Czapik A, Franczyk A. Directed cis-hydrosilylation of borylalkynes to borylsilylalkenes. Chem Commun (Camb) 2022; 58:12046-12049. [DOI: 10.1039/d2cc04318a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Directed by the choice of catalyst cis-hydrosilylation of borylalkynes leads to novel borylsilylalkenes which are crucial synthons for the introduction of the carbon–carbon double bonds in organic synthesis.
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Affiliation(s)
- Kinga Stefanowska
- Center for Advanced Technology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 10, Poznań 61-614, Poland
| | - Tomasz Sokolnicki
- Center for Advanced Technology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 10, Poznań 61-614, Poland
- Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, Poznań 61-614, Poland
| | - Jędrzej Walkowiak
- Center for Advanced Technology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 10, Poznań 61-614, Poland
| | - Agnieszka Czapik
- Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, Poznań 61-614, Poland
| | - Adrian Franczyk
- Center for Advanced Technology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 10, Poznań 61-614, Poland
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20
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Geier SJ, Vogels CM, Melanson JA, Westcott SA. The transition metal-catalysed hydroboration reaction. Chem Soc Rev 2022; 51:8877-8922. [DOI: 10.1039/d2cs00344a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review covers the development of the transition metal-catalysed hydroboration reaction, from its beginnings in the 1980s to more recent developments including earth-abundant catalysts and an ever-expanding array of substrates.
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Affiliation(s)
- Stephen J. Geier
- Department of Chemistry and Biochemistry, Mount Allison University, Sackville, NB E4L 1G8, Canada
| | - Christopher M. Vogels
- Department of Chemistry and Biochemistry, Mount Allison University, Sackville, NB E4L 1G8, Canada
| | - Jennifer A. Melanson
- Department of Chemistry and Biochemistry, Mount Allison University, Sackville, NB E4L 1G8, Canada
| | - Stephen A. Westcott
- Department of Chemistry and Biochemistry, Mount Allison University, Sackville, NB E4L 1G8, Canada
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21
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Wang Y, Gong K, Zhang H, Liu Y, Wei D. Mechanism of a cobalt-catalyzed hydroarylation reaction and origin of stereoselectivity. Catal Sci Technol 2022. [DOI: 10.1039/d2cy00780k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In the present study, the mechanism of a cobalt-catalyzed hydroarylation reaction between N-pyridylindole and 1,6-enynes and the origin of its stereoselectivity have been systematically investigated using the DFT calculation method.
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Affiliation(s)
- Yang Wang
- Department of Material and Chemical Engineering, Zhengzhou University of Light Industry, 136 Science Avenue, Zhengzhou, Henan Province, 450002, PR China
| | - Kaili Gong
- Department of Material and Chemical Engineering, Zhengzhou University of Light Industry, 136 Science Avenue, Zhengzhou, Henan Province, 450002, PR China
| | - Han Zhang
- Department of Material and Chemical Engineering, Zhengzhou University of Light Industry, 136 Science Avenue, Zhengzhou, Henan Province, 450002, PR China
| | - Yue Liu
- Department of Material and Chemical Engineering, Zhengzhou University of Light Industry, 136 Science Avenue, Zhengzhou, Henan Province, 450002, PR China
| | - Donghui Wei
- College of Chemistry (Center of Green Catalysis), Zhengzhou University, 100 Science Avenue, Zhengzhou, Henan Province, 450001, PR China
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22
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González MJ, Bauer F, Breit B. Cobalt-Catalyzed Hydroboration of Terminal and Internal Alkynes. Org Lett 2021; 23:8199-8203. [PMID: 34618449 DOI: 10.1021/acs.orglett.1c02854] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel methodology to access synthetically versatile vinylboronic esters through a ligand-controlled cobalt-catalyzed hydroboration of terminal and internal alkynes is reported. The approach relies on the in situ reduction of Co(II) by H-BPin in the presence of bisphosphine ligands generating catalytically active Co(I) hydride complexes. This procedure avoids the use of stoichiometric amounts of base, and no boron-containing byproducts are generated which is translated into high functional group tolerance and atom economy.
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Affiliation(s)
- María J González
- Institut für Organische Chemie, Albert-Ludwigs-Universität 21, 79104 Freiburg, Germany
| | - Felix Bauer
- Institut für Organische Chemie, Albert-Ludwigs-Universität 21, 79104 Freiburg, Germany
| | - Bernhard Breit
- Institut für Organische Chemie, Albert-Ludwigs-Universität 21, 79104 Freiburg, Germany
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23
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Ott JC, Suturina EA, Kuprov I, Nehrkorn J, Schnegg A, Enders M, Gade LH. Observability of Paramagnetic NMR Signals at over 10 000 ppm Chemical Shifts. Angew Chem Int Ed Engl 2021; 60:22856-22864. [PMID: 34351041 PMCID: PMC8518043 DOI: 10.1002/anie.202107944] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Indexed: 12/27/2022]
Abstract
We report an experimental observation of 31 P NMR resonances shifted by over 10 000 ppm (meaning percent range, and a new record for solutions), and similar 1 H chemical shifts, in an intermediate-spin square planar ferrous complex [tBu (PNP)Fe-H], where PNP is a carbazole-based pincer ligand. Using a combination of electronic structure theory, nuclear magnetic resonance, magnetometry, and terahertz electron paramagnetic resonance, the influence of magnetic anisotropy and zero-field splitting on the paramagnetic shift and relaxation enhancement is investigated. Detailed spin dynamics simulations indicate that, even with relatively slow electron spin relaxation (T1 ≈10-11 s), it remains possible to observe NMR signals of directly metal-bonded atoms because pronounced rhombicity in the electron zero-field splitting reduces nuclear paramagnetic relaxation enhancement.
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Affiliation(s)
- Jonas C. Ott
- Anorganisch-Chemisches InstitutUniversität HeidelbergIm Neuenheimer Feld 27669120HeidelbergGermany
| | | | - Ilya Kuprov
- School of ChemistryUniversity of SouthamptonSouthamptonSO17 1BJUK
| | - Joscha Nehrkorn
- EPR Research GroupMPI for Chemical Energy ConversionStiftstrasse 34–3645470Mülheim RuhrGermany
| | - Alexander Schnegg
- EPR Research GroupMPI for Chemical Energy ConversionStiftstrasse 34–3645470Mülheim RuhrGermany
| | - Markus Enders
- Anorganisch-Chemisches InstitutUniversität HeidelbergIm Neuenheimer Feld 27669120HeidelbergGermany
| | - Lutz H. Gade
- Anorganisch-Chemisches InstitutUniversität HeidelbergIm Neuenheimer Feld 27669120HeidelbergGermany
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24
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Ott JC, Suturina EA, Kuprov I, Nehrkorn J, Schnegg A, Enders M, Gade LH. Observability of Paramagnetic NMR Signals at over 10 000 ppm Chemical Shifts. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jonas C. Ott
- Anorganisch-Chemisches Institut Universität Heidelberg Im Neuenheimer Feld 276 69120 Heidelberg Germany
| | | | - Ilya Kuprov
- School of Chemistry University of Southampton Southampton SO17 1BJ UK
| | - Joscha Nehrkorn
- EPR Research Group MPI for Chemical Energy Conversion Stiftstrasse 34–36 45470 Mülheim Ruhr Germany
| | - Alexander Schnegg
- EPR Research Group MPI for Chemical Energy Conversion Stiftstrasse 34–36 45470 Mülheim Ruhr Germany
| | - Markus Enders
- Anorganisch-Chemisches Institut Universität Heidelberg Im Neuenheimer Feld 276 69120 Heidelberg Germany
| | - Lutz H. Gade
- Anorganisch-Chemisches Institut Universität Heidelberg Im Neuenheimer Feld 276 69120 Heidelberg Germany
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25
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Ton NNH, Mai BK, Nguyen TV. Tropylium-Promoted Hydroboration Reactions: Mechanistic Insights Via Experimental and Computational Studies. J Org Chem 2021; 86:9117-9133. [PMID: 34134487 DOI: 10.1021/acs.joc.1c01208] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hydroboration reaction of alkynes is one of the most synthetically powerful tools to access organoboron compounds, versatile precursors for cross-coupling chemistry. This type of reaction has traditionally been mediated by transition-metal or main group catalysts. Herein, we report a novel method using tropylium salts, typically known as organic oxidants and Lewis acids, to promote the hydroboration reaction of alkynes. A broad range of vinylboranes can be easily accessed via this metal-free protocol. Similar hydroboration reactions of alkenes and epoxides can also be efficiently catalyzed by the same tropylium catalysts. Experimental studies and DFT calculations suggested that the reaction follows an uncommon mechanistic pathway, which is triggered by the hydride abstraction of pinacolborane with tropylium ion. This is followed by a series of in situ counterion-activated substituent exchanges to generate boron intermediates that promote the hydroboration reaction.
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Affiliation(s)
- Nhan N H Ton
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Binh Khanh Mai
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Thanh Vinh Nguyen
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
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26
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Mutoh Y, Yamamoto K, Mohara Y, Saito S. (Z)-Selective Hydrosilylation and Hydroboration of Terminal Alkynes Enabled by Ruthenium Complexes with an N-Heterocyclic Carbene Ligand. CHEM REC 2021; 21:3429-3441. [PMID: 34028185 DOI: 10.1002/tcr.202100083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 11/08/2022]
Abstract
Metal-catalyzed trans-1,2-hydrosilylations and hydroborations of terminal alkynes that generate synthetically valuable (Z)-alkenylsilanes and (Z)-alkenylboranes remain challenging due to the (E)-selective nature of the reactions and the formation of the thermodynamically unfavorable (Z)-isomer. The development of new, efficient catalytic systems for the (Z)-selective hydrosilylation and hydroboration of terminal alkynes is thus highly desirable from a fundamental perspective as it would deepen our understanding of the metal-catalyzed (Z)-selective hydrosilylation and hydroboration of terminal alkynes. This personal account describes our research for developing a ruthenium complex that can efficiently catalyze the hydrosilylation and hydroboration of terminal alkynes, and for exploring the factors controlling (Z)-selectivity of the reactions. Our effort into the activation of B-protected boronic acids, R-B(dan) (dan=naphthalene-1,8-diaminato), that was believed not to participate in Suzuki-Miyaura cross-coupling, is also discussed.
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Affiliation(s)
- Yuichiro Mutoh
- Department of Chemistry, Faculty of Science, Tokyo University of Science 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan.,RIKEN Center for Sustainable Resource Science 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Kensuke Yamamoto
- Department of Chemistry, Faculty of Science, Tokyo University of Science 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Yusei Mohara
- Department of Chemistry, Faculty of Science, Tokyo University of Science 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Shinichi Saito
- Department of Chemistry, Faculty of Science, Tokyo University of Science 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan
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27
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Poitras AM, Oliemuller LK, Hatzis GP, Thomas CM. Highly Selective Hydroboration of Terminal Alkenes Catalyzed by a Cobalt Pincer Complex Featuring a Central Reactive N-Heterocyclic Phosphido Fragment. Organometallics 2021. [DOI: 10.1021/acs.organomet.0c00741] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Andrew M. Poitras
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Leah K. Oliemuller
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Gillian P. Hatzis
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Christine M. Thomas
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
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28
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Ott JC, Wadepohl H, Gade LH. Metalloradical Reactivity, Charge Transfer, and Atom Abstractions in a T-Shaped Iron(I) Complex. Inorg Chem 2021; 60:3927-3938. [DOI: 10.1021/acs.inorgchem.0c03724] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Jonas C. Ott
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Hubert Wadepohl
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Lutz H. Gade
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
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29
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Matveeva R, Blasius CK, Wadepohl H, Gade LH. Reactivity of a T-shaped cobalt(I) pincer-complex. Dalton Trans 2021; 50:6802-6810. [PMID: 34032245 DOI: 10.1039/d1dt00277e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactivity of a paramagnetic T-shaped cobalt(i) complex, [(iPrboxmi)Co], stabilised by a monoanionic bis(oxazolinylmethylidene)-isoindolate (boxmi) NNN pincer ligand is described. The exposure to carbon monoxide as an additional neutral ligand resulted in the square-planar species [(iPrboxmi)Co(CO)], accompanied by a change in the electronic spin state from S = 1 to S = 0. In contrast, upon treatment with trimethylphosphine the formation of the distorted tetrahedral complex [(iPrboxmi)Co(PMe3)] was observed (S = 1). Reacting [(iPrboxmi)Co] with iodine (I2), organic peroxides (tBu2O2, (SiMe3)2O2) and diphenyldisulphide (Ph2S2) yielded the tetracoordinated complexes [(iPrboxmi)CoI], [(iPrboxmi)Co(OtBu)], [(iPrboxmi)Co(OSiMe3)] and [(iPrboxmi)Co(SPh)], respectively, demonstrating the capability of the boxmi-supported cobalt(i) complex to homolytically cleave bonds and thus its distinct one-electron reactivity. Furthermore, a square-planar cobalt(ii) alkynyl complex [(iPrboxmi)Co(CCArF)] was identified as the main product in the reaction between [(iPrboxmi)Co] and a terminal alkyne, 4-fluoro-1-ethynylbenzene. Putting such species in the context of the previously investigated hydroboration catalysis, its stoichiometric reaction with pinacolborane revealed its potential conversion into a cobalt(ii) hydride complex, thus confirming its original attribution as off-cycle species.
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Affiliation(s)
- Regina Matveeva
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| | - Clemens K Blasius
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| | - Hubert Wadepohl
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| | - Lutz H Gade
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
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30
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Blasius CK, Vasilenko V, Matveeva R, Wadepohl H, Gade LH. Reaction Pathways and Redox States in α-Selective Cobalt-Catalyzed Hydroborations of Alkynes. Angew Chem Int Ed Engl 2020; 59:23010-23014. [PMID: 32889757 PMCID: PMC7756293 DOI: 10.1002/anie.202009625] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 09/04/2020] [Indexed: 11/19/2022]
Abstract
Cobalt(II) alkyl complexes supported by a monoanionic NNN pincer ligand are pre‐catalysts for the regioselective hydroboration of terminal alkynes, yielding the Markovnikov products with α:β‐(E) ratios of up to 97:3. A cobalt(II) hydride and a cobalt(II) vinyl complex appear to determine the main reaction pathway. In a background reaction the highly reactive hydrido species specifically converts to a coordinatively unsaturated cobalt(I) complex which was found to re‐enter the main catalytic cycle.
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Affiliation(s)
- Clemens K Blasius
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Vladislav Vasilenko
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Regina Matveeva
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Hubert Wadepohl
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Lutz H Gade
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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