51
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Bläsing K, Bresien J, Labbow R, Michalik D, Schulz A, Thomas M, Villinger A. Borane Adducts of Hydrazoic Acid and Organic Azides: Intermediates for the Formation of Aminoboranes. Angew Chem Int Ed Engl 2019; 58:6540-6544. [PMID: 30888089 DOI: 10.1002/anie.201902226] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Indexed: 12/16/2022]
Abstract
The reaction of HN3 with the strong Lewis acid B(C6 F5 )3 led to the formation of a very labile HN3 ⋅B(C6 F5 )3 adduct, which decomposed to an aminoborane, H(C6 F5 )NB(C6 F5 )2 , above -20 °C with release of molecular nitrogen and simultaneous migration of a C6 F5 group from boron to the nitrogen atom. The intermediary formation of azide-borane adducts with B(C6 F5 )3 was also demonstrated for a series of organic azides, RN3 (R=Me3 Si, Ph, 3,5-(CF3 )2 C6 H3 ), which also underwent Staudinger-like decomposition along with C6 F5 group migration. In accord with experiment, computations revealed rather small barriers towards nitrogen release for these highly labile azide adducts for all organic substituents except R=Me3 Si (m.p. 120 °C, Tdec =189 °C). Hydrolysis of the aminoboranes provided C6 F5 -substituted amines, HN(R)(C6 F5 ), in good yields.
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Affiliation(s)
- Kevin Bläsing
- Anorganische Chemie, Institut für Chemie, Universität Rostock, A.-Einstein-Str. 3a, 18059, Rostock, Germany
| | - Jonas Bresien
- Anorganische Chemie, Institut für Chemie, Universität Rostock, A.-Einstein-Str. 3a, 18059, Rostock, Germany
| | - René Labbow
- Anorganische Chemie, Institut für Chemie, Universität Rostock, A.-Einstein-Str. 3a, 18059, Rostock, Germany
| | - Dirk Michalik
- Anorganische Chemie, Institut für Chemie, Universität Rostock, A.-Einstein-Str. 3a, 18059, Rostock, Germany.,Materialdesign, Leibniz-Institut für Katalyse an der Universität Rostock, A.-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Axel Schulz
- Anorganische Chemie, Institut für Chemie, Universität Rostock, A.-Einstein-Str. 3a, 18059, Rostock, Germany.,Materialdesign, Leibniz-Institut für Katalyse an der Universität Rostock, A.-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Max Thomas
- Anorganische Chemie, Institut für Chemie, Universität Rostock, A.-Einstein-Str. 3a, 18059, Rostock, Germany
| | - Alexander Villinger
- Anorganische Chemie, Institut für Chemie, Universität Rostock, A.-Einstein-Str. 3a, 18059, Rostock, Germany
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52
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Mu Y, Nguyen TT, van der Mei FW, Schrock RR, Hoveyda AH. Traceless Protection for More Broadly Applicable Olefin Metathesis. Angew Chem Int Ed Engl 2019; 58:5365-5370. [PMID: 30747464 PMCID: PMC6453129 DOI: 10.1002/anie.201901132] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Indexed: 12/27/2022]
Abstract
An operationally simple in situ protection/deprotection strategy that significantly expands the scope of kinetically controlled catalytic Z- and E-selective olefin metathesis is introduced. Prior to the addition of a sensitive Mo- or Ru-based complex, treatment of a hydroxy- or a carboxylic-acid-containing olefin with commercially available HB(pin) or readily accessible HB(trip)2 (pin=pinacolato, trip=2,4,6-tri(isopropyl)phenyl) for 15 min is sufficient for efficient generation of a desired product. Routine workup leads to quantitative deprotection. A range of stereochemically defined Z- and E-alkenyl chlorides, bromides, fluorides, and boronates or Z-trifluoromethyl-substituted alkenes with a hydroxy or carboxylic acid group were thus prepared in 51-97 % yield with 93 to >98 % stereoselectivity. We also show that, regardless of whether a polar functional unit is present or not, a small amount of HB(pin) may be used to remove residual water, significantly enhancing efficiency.
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Affiliation(s)
- Yucheng Mu
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA, 02467, USA
| | - Thach T Nguyen
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA, 02467, USA
| | - Farid W van der Mei
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA, 02467, USA
| | - Richard R Schrock
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Amir H Hoveyda
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA, 02467, USA
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53
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Revisiting the reduction of indoles by hydroboranes: A combined experimental and computational study. Tetrahedron 2019. [DOI: 10.1016/j.tet.2019.02.048] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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54
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Mu Y, Nguyen TT, van der Mei FW, Schrock RR, Hoveyda AH. Traceless Protection for More Broadly Applicable Olefin Metathesis. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201901132] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Yucheng Mu
- Department of ChemistryMerkert Chemistry CenterBoston College Chestnut Hill MA 02467 USA
| | - Thach T. Nguyen
- Department of ChemistryMerkert Chemistry CenterBoston College Chestnut Hill MA 02467 USA
| | - Farid W. van der Mei
- Department of ChemistryMerkert Chemistry CenterBoston College Chestnut Hill MA 02467 USA
| | - Richard R. Schrock
- Department of ChemistryMassachusetts Institute of Technology Cambridge MA 02139 USA
| | - Amir H. Hoveyda
- Department of ChemistryMerkert Chemistry CenterBoston College Chestnut Hill MA 02467 USA
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55
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Dasgupta R, Das S, Hiwase S, Pati SK, Khan S. N-Heterocyclic Germylene and Stannylene Catalyzed Cyanosilylation and Hydroboration of Aldehydes. Organometallics 2019. [DOI: 10.1021/acs.organomet.8b00673] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rajarshi Dasgupta
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, Pune 411 008, India
| | - Shubhajit Das
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur-Bangalore 560064, India
| | - Shweta Hiwase
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, Pune 411 008, India
| | - Swapan K. Pati
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur-Bangalore 560064, India
| | - Shabana Khan
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, Pune 411 008, India
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56
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Kuciński K, Hreczycho G. A Highly Effective Route to Si-O-Si Moieties through O-Silylation of Silanols and Polyhedral Oligomeric Silsesquioxane Silanols with Disilazanes. CHEMSUSCHEM 2019; 12:1043-1048. [PMID: 30536641 DOI: 10.1002/cssc.201802757] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Indexed: 06/09/2023]
Abstract
A simple and highly practical catalyst-free O-silylation of silanols with commercially available disilazanes has been developed under mild conditions. In the case of polyhedral oligomeric silsesquioxane (POSS) silanols and some other silanols, it was necessary to use catalytic amounts of inexpensive Bi(OTf)3 as additional catalyst. This efficient chlorine-free protocol involves the synthesis of a wide range of important organosilicon derivatives such as unsymmetrical disiloxanes and functionalized silsesquioxanes.
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Affiliation(s)
- Krzysztof Kuciński
- Faculty of Chemistry, Adam Mickiewicz University in Poznań, Umultowska 89b, 61-614, Poznań, Poland
| | - Grzegorz Hreczycho
- Faculty of Chemistry, Adam Mickiewicz University in Poznań, Umultowska 89b, 61-614, Poznań, Poland
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57
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Junor GP, Romero EA, Chen X, Jazzar R, Bertrand G. Readily Available Primary Aminoboranes as Powerful Reagents for Aldimine Synthesis. Angew Chem Int Ed Engl 2019; 58:2875-2878. [DOI: 10.1002/anie.201814081] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Indexed: 01/18/2023]
Affiliation(s)
- Glen P. Junor
- UCSD-CNRS Joint Research Laboratory (UMI 3555)Department of Chemistry and BiochemistryUniversity of California San Diego, La Jolla CA 92093-0358 USA
| | - Erik A. Romero
- UCSD-CNRS Joint Research Laboratory (UMI 3555)Department of Chemistry and BiochemistryUniversity of California San Diego, La Jolla CA 92093-0358 USA
| | - Xi Chen
- UCSD-CNRS Joint Research Laboratory (UMI 3555)Department of Chemistry and BiochemistryUniversity of California San Diego, La Jolla CA 92093-0358 USA
| | - Rodolphe Jazzar
- UCSD-CNRS Joint Research Laboratory (UMI 3555)Department of Chemistry and BiochemistryUniversity of California San Diego, La Jolla CA 92093-0358 USA
| | - Guy Bertrand
- UCSD-CNRS Joint Research Laboratory (UMI 3555)Department of Chemistry and BiochemistryUniversity of California San Diego, La Jolla CA 92093-0358 USA
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58
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Huchenski BSN, Speed AWH. Protic additives or impurities promote imine reduction with pinacolborane. Org Biomol Chem 2019; 17:1999-2004. [PMID: 30426130 DOI: 10.1039/c8ob02330a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We report here that addition of stoichiometric amounts of alcohols or water to mixtures of imines and pinacolborane promote reduction reactions. The reactions of several imines were examined, revealing that alkyl imines were reduced, while aniline derived imines were not effectively reduced. The use of binol as an additive resulted in modest enantioinduction, however other chiral additives that were screened gave negligible enantioinduction. While the reactions described herein are not competitive in conversion with established imine reduction technologies, this work reveals that the presence of protic impurities must be considered as a promoter of side reactions in catalyzed imine hydroborations. Amines also promote imine reduction in certain cases, raising the possibility of a slow autocatalytic reaction. The ability of water or other protic impurities to promote the reduction of imines with pinacolborane represents an important identification of a potential source of background reaction in catalyzed reductions of imines.
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Affiliation(s)
- Blake S N Huchenski
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, Nova Scotia, CanadaB3H 4R2.
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59
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Junor GP, Romero EA, Chen X, Jazzar R, Bertrand G. Readily Available Primary Aminoboranes as Powerful Reagents for Aldimine Synthesis. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201814081] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Glen P. Junor
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego, La Jolla CA 92093-0358 USA
| | - Erik A. Romero
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego, La Jolla CA 92093-0358 USA
| | - Xi Chen
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego, La Jolla CA 92093-0358 USA
| | - Rodolphe Jazzar
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego, La Jolla CA 92093-0358 USA
| | - Guy Bertrand
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego, La Jolla CA 92093-0358 USA
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60
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Harinath A, Bhattacharjee J, Panda TK. Facile reduction of carboxylic acids to primary alcohols under catalyst-free and solvent-free conditions. Chem Commun (Camb) 2019; 55:1386-1389. [PMID: 30607398 DOI: 10.1039/c8cc08841a] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We report the development of a facile protocol for the deoxygenative hydroboration of aliphatic and aryl carboxylic acids to afford corresponding primary alcohols under solvent-free and catalyst-free conditions. The reaction proceeds under ambient temperature exhibits good tolerance towards various functional groups and generates quantitative yields. The plausible mechanism involves the formation of Lewis acid-base adducts as well as the liberation of hydrogen gas.
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Affiliation(s)
- Adimulam Harinath
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502285, Telangana, India.
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61
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Wang W, Luo M, Yao W, Ma M, Pullarkat SA, Xu L, Leung PH. Catalyst-free and solvent-free hydroboration of ketones. NEW J CHEM 2019. [DOI: 10.1039/c9nj02722j] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The hydroboration of a wide range of ketones with HBpin under catalyst-free and solvent-free conditions was reported in high yields.
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Affiliation(s)
- Weifan Wang
- Department of Chemistry and Materials Science
- College of Science
- Nanjing Forestry University
- Nanjing 210037
- China
| | - Man Luo
- Department of Chemistry and Materials Science
- College of Science
- Nanjing Forestry University
- Nanjing 210037
- China
| | - Weiwei Yao
- College of Pharmacy
- Nanjing University of Chinese Medicine
- Nanjing 210023
- China
| | - Mengtao Ma
- Department of Chemistry and Materials Science
- College of Science
- Nanjing Forestry University
- Nanjing 210037
- China
| | - Sumod A. Pullarkat
- Division of Chemistry & Biological Chemistry
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
- Singapore
| | - Li Xu
- Department of Chemistry and Materials Science
- College of Science
- Nanjing Forestry University
- Nanjing 210037
- China
| | - Pak-Hing Leung
- Division of Chemistry & Biological Chemistry
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
- Singapore
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62
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Espinal-Viguri M, Neale SE, Coles NT, Macgregor SA, Webster RL. Room Temperature Iron-Catalyzed Transfer Hydrogenation and Regioselective Deuteration of Carbon-Carbon Double Bonds. J Am Chem Soc 2018; 141:572-582. [PMID: 30518206 DOI: 10.1021/jacs.8b11553] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An iron catalyst has been developed for the transfer hydrogenation of carbon-carbon multiple bonds. Using a well-defined β-diketiminate iron(II) precatalyst, a sacrificial amine and a borane, even simple, unactivated alkenes such as 1-hexene undergo hydrogenation within 1 h at room temperature. Tuning the reagent stoichiometry allows for semi- and complete hydrogenation of terminal alkynes. It is also possible to hydrogenate aminoalkenes and aminoalkynes without poisoning the catalyst through competitive amine ligation. Furthermore, by exploiting the separate protic and hydridic nature of the reagents, it is possible to regioselectively prepare monoisotopically labeled products. DFT calculations define a mechanism for the transfer hydrogenation of propene with nBuNH2 and HBpin that involves the initial formation of an iron(II)-hydride active species, 1,2-insertion of propene, and rate-limiting protonolysis of the resultant alkyl by the amine N-H bond. This mechanism is fully consistent with the selective deuteration studies, although the calculations also highlight alkene hydroboration and amine-borane dehydrocoupling as competitive processes. This was resolved by reassessing the nature of the active transfer hydrogenation agent: experimentally, a gel is observed in catalysis, and calculations suggest this can be formulated as an oligomeric species comprising H-bonded amine-borane adducts. Gel formation serves to reduce the effective concentrations of free HBpin and nBuNH2 and so disfavors both hydroboration and dehydrocoupling while allowing alkene migratory insertion (and hence transfer hydrogenation) to dominate.
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Affiliation(s)
- Maialen Espinal-Viguri
- Department of Chemistry , University of Bath , Claverton Down, Bath BA2 7AY , United Kingdom
| | - Samuel E Neale
- Institute of Chemical Sciences , Heriot-Watt University , Edinburgh EH14 4AS , United Kingdom
| | - Nathan T Coles
- Department of Chemistry , University of Bath , Claverton Down, Bath BA2 7AY , United Kingdom
| | - Stuart A Macgregor
- Institute of Chemical Sciences , Heriot-Watt University , Edinburgh EH14 4AS , United Kingdom
| | - Ruth L Webster
- Department of Chemistry , University of Bath , Claverton Down, Bath BA2 7AY , United Kingdom
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63
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Franz D, Inoue S. Cationic Complexes of Boron and Aluminum: An Early 21st Century Viewpoint. Chemistry 2018; 25:2898-2926. [PMID: 30113744 DOI: 10.1002/chem.201803370] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Indexed: 01/03/2023]
Abstract
Boron and aluminum are lighter Group 13 elements, found in daily life commodities, and considered environmentally benign. Nevertheless, they markedly differ in their elemental properties (e.g., metal character, atomic radius). The use of Lewis acidic complexes of boron and aluminum for methods of bond activation and catalysis (e.g., hydrogenation of unsaturated substrates, polymerization of olefins and epoxides) is quickly expanding. The introduction of cationic charge may boost the metalloid-centered Lewis acidity and allow for its fine-tuning particularly with regard to preference for "hard" or "soft" Lewis bases (i.e., substrates). Especially the isolation of low-coordinate cations (number of ligand atoms smaller than four) demands elaborate techniques of thermodynamic and kinetic stabilization (i.e., electronic saturation and steric shielding) by a ligand system. Furthermore, the properties of the solvent and the counteranion must be considered with care. Here, selected examples of boron and aluminum cations are described.
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Affiliation(s)
- Daniel Franz
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstr. 4, 85748, Garching bei München, Germany
| | - Shigeyoshi Inoue
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstr. 4, 85748, Garching bei München, Germany
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64
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Zhang X, Zeng R, Feng X, Dai QS, Liu Y, Liu YQ, Wang QW, Li QZ, Li JL. Intermolecular Cyclopropanation of Iodonium Ylides and Electron-Deficient Alkenes through a Highly Efficient Catalyst-Free Process. ASIAN J ORG CHEM 2018. [DOI: 10.1002/ajoc.201800499] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Xiang Zhang
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province Sichuan Industrial Institute of Antibiotics; Chengdu University; Chengdu 610052 PR China
- Chengdu Institute of Organic Chemistry; Chinese Academy of Sciences; Chengdu 610041 PR China
| | - Rong Zeng
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province Sichuan Industrial Institute of Antibiotics; Chengdu University; Chengdu 610052 PR China
| | - Xin Feng
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province Sichuan Industrial Institute of Antibiotics; Chengdu University; Chengdu 610052 PR China
| | - Qing-Song Dai
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province Sichuan Industrial Institute of Antibiotics; Chengdu University; Chengdu 610052 PR China
| | - Yue Liu
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province Sichuan Industrial Institute of Antibiotics; Chengdu University; Chengdu 610052 PR China
| | - Yan-Qing Liu
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province Sichuan Industrial Institute of Antibiotics; Chengdu University; Chengdu 610052 PR China
| | - Qi-Wei Wang
- Chengdu Institute of Organic Chemistry; Chinese Academy of Sciences; Chengdu 610041 PR China
| | - Qing-Zhu Li
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province Sichuan Industrial Institute of Antibiotics; Chengdu University; Chengdu 610052 PR China
| | - Jun-Long Li
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province Sichuan Industrial Institute of Antibiotics; Chengdu University; Chengdu 610052 PR China
- Chengdu Institute of Organic Chemistry; Chinese Academy of Sciences; Chengdu 610041 PR China
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65
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Harinath A, Bhattacharjee J, Nayek HP, Panda TK. Alkali metal complexes as efficient catalysts for hydroboration and cyanosilylation of carbonyl compounds. Dalton Trans 2018; 47:12613-12622. [PMID: 30043795 DOI: 10.1039/c8dt02032a] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We report here reactions between the N-adamantyliminopyrolyl ligand 2-(AdN[double bond, length as m-dash]CH)-C4H3NH (L-H) and alkali metal hexamethyldisilazides [MN(SiMe3)2] (M = Li, Na and K) to afford the dimeric [{2-(AdN[double bond, length as m-dash]CH)-C4H3NLi(THF)}2] (1), [{2-(AdN[double bond, length as m-dash]CH)-C4H3N}{Na(THF)1.5}2] (2) and polymeric [{2-(AdN[double bond, length as m-dash]CH)-C4H3NK(THF)}n] (3) complexes at ambient temperature. A one-pot reaction between L-H, [KN(SiMe3)2] and alkaline earth metal diiodide (AeI2) in a 2 : 2 : 1 molar ratio, which resulted in the formation of a heteroleptic Ae metal complex [κ2-{2-(AdN[double bond, length as m-dash]CH)-C4H3N}2Ae(THF)2] [Ae = Mg (4), Ca (5)], is also reported. The solid-state structures of complexes 1, 3 and 4 were established through single-crystal X-ray diffraction analysis. The alkali and alkaline earth metal complexes 1-5 were utilised as precatalysts for the catalytic hydroboration of pinacolborane (HBpin) with aldehydes and ketones, and potassium complex 3 was identified as a competent catalyst under mild conditions. Additionally, cyanosilylation of carbonyl compounds was explored with trimethylsilyl cyanide and aldehydes/ketones, using the alkali metal precatalyst 3 under mild conditions. In both catalytic processes, the potassium catalyst 3 exhibited high tolerance towards a number of functional groups.
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Affiliation(s)
- Adimulam Harinath
- Department of Chemistry, Indian Institute of Technology Hyderabad Kandi - 502 285, Sangareddy, Telangana, India.
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66
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Macaulay CM, Gustafson SJ, Fuller JT, Kwon DH, Ogawa T, Ferguson MJ, McDonald R, Lumsden MD, Bischof SM, Sydora OL, Ess DH, Stradiotto M, Turculet L. Alkene Isomerization–Hydroboration Catalyzed by First-Row Transition-Metal (Mn, Fe, Co, and Ni) N-Phosphinoamidinate Complexes: Origin of Reactivity and Selectivity. ACS Catal 2018. [DOI: 10.1021/acscatal.8b01972] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Casper M. Macaulay
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, P.O. 15000, Halifax, Nova Scotia B3H 4R2, Canada
| | - Samantha J. Gustafson
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Jack T. Fuller
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Doo-Hyun Kwon
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Takahiko Ogawa
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, P.O. 15000, Halifax, Nova Scotia B3H 4R2, Canada
| | - Michael J. Ferguson
- X-Ray Crystallography Laboratory, Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Robert McDonald
- X-Ray Crystallography Laboratory, Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Michael D. Lumsden
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, P.O. 15000, Halifax, Nova Scotia B3H 4R2, Canada
| | - Steven M. Bischof
- Research and Technology, Chevron Phillips Chemical Company LP, 1862 Kingwood Drive, Kingwood, Texas 77339, United States
| | - Orson L. Sydora
- Research and Technology, Chevron Phillips Chemical Company LP, 1862 Kingwood Drive, Kingwood, Texas 77339, United States
| | - Daniel H. Ess
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Mark Stradiotto
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, P.O. 15000, Halifax, Nova Scotia B3H 4R2, Canada
| | - Laura Turculet
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, P.O. 15000, Halifax, Nova Scotia B3H 4R2, Canada
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67
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Zhu Z, Wu X, Xu X, Wu Z, Xue M, Yao Y, Shen Q, Bao X. n-Butyllithium Catalyzed Selective Hydroboration of Aldehydes and Ketones. J Org Chem 2018; 83:10677-10683. [PMID: 30070486 DOI: 10.1021/acs.joc.8b01495] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Highly efficient and selective hydroboration of aldehydes and ketones with HBpin is achieved by using the simple and convenient n-BuLi as a catalyst. The reaction proceeds rapidly with low catalyst loading (0.1-0.5 mol %) under mild conditions. Key features include the high catalytic efficiency, exceptional functional group compatibility, ample substrate scope, and high selectivity for aldehydes over ketones. Computational studies were carried out to provide a mechanistic insight into the n-BuLi catalyzed hydroboration of aldehydes/ketones with HBpin.
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Affiliation(s)
- Zhangye Zhu
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Dushu Lake Campus , Soochow University , Suzhou 215123 , People's Republic of China
| | - Xueli Wu
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Dushu Lake Campus , Soochow University , Suzhou 215123 , People's Republic of China
| | - Xiaojuan Xu
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Dushu Lake Campus , Soochow University , Suzhou 215123 , People's Republic of China
| | - Zhenjie Wu
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Dushu Lake Campus , Soochow University , Suzhou 215123 , People's Republic of China
| | - Mingqiang Xue
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Dushu Lake Campus , Soochow University , Suzhou 215123 , People's Republic of China
| | - Yingming Yao
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Dushu Lake Campus , Soochow University , Suzhou 215123 , People's Republic of China
| | - Qi Shen
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Dushu Lake Campus , Soochow University , Suzhou 215123 , People's Republic of China
| | - Xiaoguang Bao
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Dushu Lake Campus , Soochow University , Suzhou 215123 , People's Republic of China
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68
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Moreno S, Ramos A, Carrillo-Hermosilla F, Rodríguez-Diéguez A, García-Vivó D, Fernández-Galán R, Antiñolo A. Selective Three-Component Coupling for CO 2 Chemical Fixation to Boron Guanidinato Compounds. Inorg Chem 2018; 57:8404-8413. [PMID: 29949350 DOI: 10.1021/acs.inorgchem.8b01068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A selective three-component coupling was employed to fix carbon dioxide to boron guanidinato compounds. The one-pot reaction of carbon dioxide, carbodiimides, and borylamines (ArNH)BC8H14 afforded the corresponding 1,2-adducts {R(H)N}C{N(Ar)}(NR)(CO2)BC8H14. Alternatively, the reaction with p-MeOC6H4NC or 2,6-Me2C6H3NC gave the corresponding isocyanide 1,1-adducts { i-PrHN}C{N(p-Me-C6H4)}(N i-Pr){CNAr}BC8H14. The molecular structures of products (2,6- i-Pr2C6H3NH)BC8H14 7, { i-Pr(H)N}C{N(p-MeC6H4)}(N i-Pr)(CO2)BC8H14 9, {Cy(H)N}C{N( p-MeC6H4)}(Cy)(CO2)BC8H14 13, and { i-PrHN}C{N( p-MeC6H4)}(N i-Pr){CNR″}BC8H14 (R″ = p-MeOC6H4, 2,6-Me2C6H3) 14 and 15 were established by X-ray diffraction. Density functional theory calculations at the M05-2X level of theory revealed that CO2 fixation and formation of the corresponding adduct is exothermic and proceeds via a nonchelate boron guanidinato intermediate.
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Affiliation(s)
- Sonia Moreno
- Departamento de Química Inorgánica, Orgánica y Bioquímica-Centro de Innovación en Química Avanzada (ORFEO-CINQA) , Universidad de Castilla-La Mancha , Campus Universitario , E-13071 Ciudad Real , Spain
| | - Alberto Ramos
- Departamento de Química Inorgánica, Orgánica y Bioquímica , Instituto Regional de Investigación Científica Aplicada, Universidad de Castilla-La Mancha , Campus Universitario , E-13071 Ciudad Real , Spain
| | - Fernando Carrillo-Hermosilla
- Departamento de Química Inorgánica, Orgánica y Bioquímica-Centro de Innovación en Química Avanzada (ORFEO-CINQA) , Universidad de Castilla-La Mancha , Campus Universitario , E-13071 Ciudad Real , Spain
| | - Antonio Rodríguez-Diéguez
- Departamento de Química Inorgánica, Facultad de Ciencias , Universidad de Granada , Avenida de la Fuente Nueva S/N , 18071 Granada , Spain
| | - Daniel García-Vivó
- Departamento de Química Orgánica e Inorgánica/IUQOEM , Universidad de Oviedo , E-33071 Oviedo , Spain
| | - Rafael Fernández-Galán
- Departamento de Química Inorgánica, Orgánica y Bioquímica-Centro de Innovación en Química Avanzada (ORFEO-CINQA) , Universidad de Castilla-La Mancha , Campus Universitario , E-13071 Ciudad Real , Spain
| | - Antonio Antiñolo
- Departamento de Química Inorgánica, Orgánica y Bioquímica-Centro de Innovación en Química Avanzada (ORFEO-CINQA) , Universidad de Castilla-La Mancha , Campus Universitario , E-13071 Ciudad Real , Spain
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69
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Zhu Z, Dai P, Wu Z, Xue M, Yao Y, Shen Q, Bao X. Lanthanide aryloxides catalyzed hydroboration of aldehydes and ketones. CATAL COMMUN 2018. [DOI: 10.1016/j.catcom.2018.04.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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70
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Harinath A, Bhattcharjee J, Gorantla KR, Mallik BS, Panda TK. Hydroboration, Cyanosilylation, and Sequential Cyanosilylation and Hydroboration of Carbonyl Compounds in the Presence of a TiIV
Amido Complex as an Efficient Catalyst. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800547] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Adimulam Harinath
- Department of Chemistry; Indian Institute of Technology Hyderabad; Kandi - 502 285 Sangareddy Telangana India
| | - Jayeeta Bhattcharjee
- Department of Chemistry; Indian Institute of Technology Hyderabad; Kandi - 502 285 Sangareddy Telangana India
| | - Koteswar Rao Gorantla
- Department of Chemistry; Indian Institute of Technology Hyderabad; Kandi - 502 285 Sangareddy Telangana India
| | - Bhabani S. Mallik
- Department of Chemistry; Indian Institute of Technology Hyderabad; Kandi - 502 285 Sangareddy Telangana India
| | - Tarun K. Panda
- Department of Chemistry; Indian Institute of Technology Hyderabad; Kandi - 502 285 Sangareddy Telangana India
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71
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Rauser M, Warzecha DP, Niggemann M. O2
-Mediated Oxidation of Aminoboranes through 1,2-N Migration. Angew Chem Int Ed Engl 2018; 57:5903-5907. [DOI: 10.1002/anie.201803168] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Marian Rauser
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Daniel P. Warzecha
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Meike Niggemann
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
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72
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Rauser M, Warzecha DP, Niggemann M. O2
-Mediated Oxidation of Aminoboranes through 1,2-N Migration. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201803168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Marian Rauser
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Daniel P. Warzecha
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Meike Niggemann
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
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73
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Boudjelel M, Sosa Carrizo ED, Mallet−Ladeira S, Massou S, Miqueu K, Bouhadir G, Bourissou D. Catalytic Dehydrogenation of (Di)Amine-Boranes with a Geometrically Constrained Phosphine-Borane Lewis Pair. ACS Catal 2018. [DOI: 10.1021/acscatal.8b00152] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Maxime Boudjelel
- CNRS/Université Paul Sabatier, Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069), 118 Route de Narbonne, 31062 CEDEX 09 Toulouse, France
| | - E. Daiann Sosa Carrizo
- CNRS/UNIV PAU & PAYS ADOUR, Institut des Sciences Analytiques et de Physico-Chimie pour l’Environnement et les Matériaux (IPREM UMR 5254), Hélioparc, 2 Avenue du Président Angot, 64053 CEDEX 09 Pau, France
| | - Sonia Mallet−Ladeira
- Institut de Chimie de Toulouse (FR 2599), 118 Route de Narbonne, 31062 CEDEX 09 Toulouse, France
| | - Stéphane Massou
- Institut de Chimie de Toulouse (FR 2599), 118 Route de Narbonne, 31062 CEDEX 09 Toulouse, France
| | - Karinne Miqueu
- CNRS/UNIV PAU & PAYS ADOUR, Institut des Sciences Analytiques et de Physico-Chimie pour l’Environnement et les Matériaux (IPREM UMR 5254), Hélioparc, 2 Avenue du Président Angot, 64053 CEDEX 09 Pau, France
| | - Ghenwa Bouhadir
- CNRS/Université Paul Sabatier, Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069), 118 Route de Narbonne, 31062 CEDEX 09 Toulouse, France
| | - Didier Bourissou
- CNRS/Université Paul Sabatier, Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069), 118 Route de Narbonne, 31062 CEDEX 09 Toulouse, France
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74
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Kato K, Hirano K, Miura M. Copper-Catalyzed Regio- and Enantioselective Aminoboration of Unactivated Terminal Alkenes. Chemistry 2018; 24:5775-5778. [DOI: 10.1002/chem.201801070] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Kodai Kato
- Department of Applied Chemistry; Graduate School of Engineering, Osaka University; Suita Osaka 565-0871 Japan), Fax: (+81) 6-6879-7362
| | - Koji Hirano
- Department of Applied Chemistry; Graduate School of Engineering, Osaka University; Suita Osaka 565-0871 Japan), Fax: (+81) 6-6879-7362
| | - Masahiro Miura
- Department of Applied Chemistry; Graduate School of Engineering, Osaka University; Suita Osaka 565-0871 Japan), Fax: (+81) 6-6879-7362
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75
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Yuan K, Wang X, Wang S. Cascade Dehydrogenative Hydroboration for the Synthesis of Azaborabenzofulvenes. Org Lett 2018; 20:1617-1620. [PMID: 29484886 DOI: 10.1021/acs.orglett.8b00363] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Tandem dehydrogenative hydroboration has been established to be highly effective in the synthesis of BN isosteres of benzofulvene and derivatives. The scope of this synthetic method is applicable to a variety of substrates. Spectroscopic and computational studies indicate that the new azaborabenzofulvenes have similar electronic properties as their carbonaceous analogues.
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Affiliation(s)
- Kang Yuan
- Department of Chemistry , Queen's University , Kingston , Ontario K7L 3N6 , Canada
| | - Xiang Wang
- Department of Chemistry , Queen's University , Kingston , Ontario K7L 3N6 , Canada
| | - Suning Wang
- Department of Chemistry , Queen's University , Kingston , Ontario K7L 3N6 , Canada
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76
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Cuenca AB, Shishido R, Ito H, Fernández E. Transition-metal-free B-B and B-interelement reactions with organic molecules. Chem Soc Rev 2018; 46:415-430. [PMID: 27942683 DOI: 10.1039/c6cs00692b] [Citation(s) in RCA: 248] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This review is a guided tour along the activation modes and reactivity of B-B, B-Si, B-N, B-S, B-Se and B-P reagents, in the absence of any transition metal complex. Here are disclosed the general concepts related to the homolytic and heterolytic cleavage of B-B and B-interelement bonds, as well as the generation of new C-B and C-interelement bonds, in a selective way. The greener consequences of these novel routes facilitate the gram scale preparations of target functionalised organic compounds. Intrinsic data about the suggested mechanisms and spectroscopic evidence that supports the innovative theories are provided along the review. Since this is a stimulating area of work that has emerged within the last decade, this overview serves as the basis to understand the new trends and hopefully to generate inspiration for future discoveries in the field.
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Affiliation(s)
- Ana B Cuenca
- Dept Física Química e Inorgánica, University Rovira i Virgili, C/Marcel·lí Domingo s/n, 43007 Tarragona, Spain. and Dept. Química Orgánica, Institut Químic de Sarrià, Universitat Ramon Llull, Via Augusta, 390, Barcelona 08017, Spain
| | - Ryosuke Shishido
- Division of Chemical Process Engineering, Graduate School of Engineering Hokkaido University, Sapporo, 060-8628, Japan.
| | - Hajime Ito
- Division of Chemical Process Engineering, Graduate School of Engineering Hokkaido University, Sapporo, 060-8628, Japan.
| | - Elena Fernández
- Dept Física Química e Inorgánica, University Rovira i Virgili, C/Marcel·lí Domingo s/n, 43007 Tarragona, Spain.
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77
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Yadav S, Pahar S, Sen SS. Benz-amidinato calcium iodide catalyzed aldehyde and ketone hydroboration with unprecedented functional group tolerance. Chem Commun (Camb) 2018; 53:4562-4564. [PMID: 28393955 DOI: 10.1039/c7cc02311a] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A benz-amidinato calcium compound, [PhC(NiPr)2CaI] (1), catalyzed hydroboration of a wide range of aldehydes and ketones using pinacolborane (HBpin) at room temperature is reported. The catalyst shows functional group tolerance even towards OH and NH groups. The strategy was further extended to imines.
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Affiliation(s)
- Sandeep Yadav
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pashan, Pune 411008, India.
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78
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Fontaine FG, Rochette É. Ambiphilic Molecules: From Organometallic Curiosity to Metal-Free Catalysts. Acc Chem Res 2018; 51:454-464. [PMID: 29308653 DOI: 10.1021/acs.accounts.7b00514] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ambiphilic molecules were first used as functional ligands for transition elements, which could enable intriguing organometallic transformations. In the past decade, these intramolecular Lewis pairs, first considered organometallic curiosities, have become staples in organometallic chemistry and catalysis, acting as Z ligands, activating inert molecules using the concept of frustrated Lewis pair (FLP) chemistry, and acting as metal-free catalysts. In this Account, we detail our contribution to this blossoming field of research, focusing on the use of ambiphilic molecules as metal-free catalysts for CO2 reduction and C-H borylation reactions. A major emphasis is put on the mechanistic investigations we carried out using reactivity studies and theoretical tools, which helped us steer our research from stoichiometric transformations to highly active catalytic processes. We first report the interaction of aluminum-phosphine ambiphilic molecules with carbon dioxide. Although these Lewis pairs can bind CO2, a study of the deactivation process in the presence of CO2 and hydroboranes led us to discover that simple phosphinoborane molecules could act as active precatalysts for the hydroboration of carbon dioxide into methanol precursors. In these systems, the Lewis basic sites interact with the reducing agents rather than with the electrophilic carbon of CO2, increasing the nucleophilicity of hydroboranes. Simultaneously, the weak Lewis acids stabilize the oxygen of the gas molecule in the transition state, leading to high reaction rates. Replacing the phosphine by an amine leads to a system enabling CO2 hydrogenation, albeit only in stoichiometric transformations. Investigation of the protodeborylation deactivation of aminoboranes led us to develop metal-free catalysts for the C-H borylation of heteroarenes. By protecting the Lewis acid sites of these catalysts using fluoride, we were able to synthesize practical, air-stable precatalysts allowing the convenient synthesis of heteroarylboronic esters on a multigram scale. Contrary to general perception of FLP chemistry, we also demonstrated that a significant increase in activity could be obtained by reducing the steric bulk around the active site. These smaller systems exist as stable dimers and are more energetically costly to dissociate into active FLPs, but the approach of the substrate and the C-H activation step are significantly favored compared to the bulkier analogues. An in-depth study of the stability and reactivity of these aminoborane molecules also allowed us to develop a metal-free catalytic S-H bond borylation system, and to report stoichiometric and spontaneous B-B bond formation and Csp3-H bond activation processes, highlighting the importance of H2 release as a thermodynamic driving force in these FLP transformations.
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Affiliation(s)
- Frédéric-Georges Fontaine
- Département de Chimie,
Centre de Catalyse et Chimie Verte, Université Laval, 1045 Avenue de
la Médecine, Québec, Québec, Canada, G1V 0A6
| | - Étienne Rochette
- Département de Chimie,
Centre de Catalyse et Chimie Verte, Université Laval, 1045 Avenue de
la Médecine, Québec, Québec, Canada, G1V 0A6
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79
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Yan D, Dai P, Chen S, Xue M, Yao Y, Shen Q, Bao X. Highly efficient hydroboration of carbonyl compounds catalyzed by tris(methylcyclopentadienyl)lanthanide complexes. Org Biomol Chem 2018; 16:2787-2791. [DOI: 10.1039/c8ob00292d] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
(MeCp)3Ln complexes are reported as highly efficient catalysts in promoting hydroboration and a plausible stepwise mechanism is proposed.
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Affiliation(s)
- Dandan Yan
- Key Laboratory of Organic Synthesis of Jiangsu Province
- College of Chemistry
- Chemical Engineering and Materials Science
- Dushu Lake Campus
- Soochow University
| | - Ping Dai
- Key Laboratory of Organic Synthesis of Jiangsu Province
- College of Chemistry
- Chemical Engineering and Materials Science
- Dushu Lake Campus
- Soochow University
| | - Sufang Chen
- Key Laboratory of Organic Synthesis of Jiangsu Province
- College of Chemistry
- Chemical Engineering and Materials Science
- Dushu Lake Campus
- Soochow University
| | - Mingqiang Xue
- Key Laboratory of Organic Synthesis of Jiangsu Province
- College of Chemistry
- Chemical Engineering and Materials Science
- Dushu Lake Campus
- Soochow University
| | - Yingming Yao
- Key Laboratory of Organic Synthesis of Jiangsu Province
- College of Chemistry
- Chemical Engineering and Materials Science
- Dushu Lake Campus
- Soochow University
| | - Qi Shen
- Key Laboratory of Organic Synthesis of Jiangsu Province
- College of Chemistry
- Chemical Engineering and Materials Science
- Dushu Lake Campus
- Soochow University
| | - Xiaoguang Bao
- Key Laboratory of Organic Synthesis of Jiangsu Province
- College of Chemistry
- Chemical Engineering and Materials Science
- Dushu Lake Campus
- Soochow University
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80
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Kuciński K, Hreczycho G. Chemoselective and Catalyst-Free O-Borylation of Silanols: A Facile Access to Borasiloxanes. CHEMSUSCHEM 2017; 10:4695-4698. [PMID: 28915345 DOI: 10.1002/cssc.201701648] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Indexed: 05/22/2023]
Abstract
This paper demonstrates the first highly chemoselective syntheses of various borasiloxanes from hydroboranes and silanols, achieved through catalyst-free dehydrogenative coupling at room temperature. This green protocol, which uses easily accessible reagents, allows for the obtaining of borasiloxanes under air atmosphere and solvent-free conditions.
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Affiliation(s)
- K Kuciński
- Faculty of Chemistry, Adam Mickiewicz University in Poznań, Ul. Umultowska 89b, 61-614, Poznań, Poland
| | - G Hreczycho
- Faculty of Chemistry, Adam Mickiewicz University in Poznań, Ul. Umultowska 89b, 61-614, Poznań, Poland
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81
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Wang W, Shen X, Zhao F, Jiang H, Yao W, Pullarkat SA, Xu L, Ma M. Ytterbium-Catalyzed Hydroboration of Aldehydes and Ketones. J Org Chem 2017; 83:69-74. [PMID: 29181979 DOI: 10.1021/acs.joc.7b02076] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The well-defined heavy rare-earth ytterbium iodide complex 1 (L2YbI) has been successfully employed as an efficient catalyst for the hydroboration of a wide range of aldehydes and ketones with pinacolborane (HBpin) at room temperature. The protocol requires low catalyst loadings (0.1-0.5 mol %) and proceeds rapidly (>99% conversion in <10 min). Additionally, catalyst 1 shows a good functional group tolerance even toward the hydroxyl and amino moieties and displays chemoselective hydroboration of aldehydes over ketones under mild conditions.
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Affiliation(s)
- Weifan Wang
- College of Science, Nanjing Forestry University , Nanjing 210037, People's Republic of China
| | - Xingchao Shen
- College of Science, Nanjing Forestry University , Nanjing 210037, People's Republic of China
| | - Fengyi Zhao
- College of Science, Nanjing Forestry University , Nanjing 210037, People's Republic of China
| | - Huan Jiang
- College of Science, Nanjing Forestry University , Nanjing 210037, People's Republic of China
| | - Weiwei Yao
- College of Pharmacy, Nanjing University of Chinese Medicine , Nanjing 210023, People's Republic of China
| | - Sumod A Pullarkat
- Division of Chemistry & Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore
| | - Li Xu
- College of Science, Nanjing Forestry University , Nanjing 210037, People's Republic of China
| | - Mengtao Ma
- College of Science, Nanjing Forestry University , Nanjing 210037, People's Republic of China
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82
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McLellan R, Kennedy AR, Mulvey RE, Orr SA, Robertson SD. 1-Alkali-metal-2-alkyl-1,2-dihydropyridines: Soluble Hydride Surrogates for Catalytic Dehydrogenative Coupling and Hydroboration Applications. Chemistry 2017; 23:16853-16861. [PMID: 28940713 PMCID: PMC5820744 DOI: 10.1002/chem.201703609] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Indexed: 01/27/2023]
Abstract
Equipped with excellent hydrocarbon solubility, the lithium hydride surrogate 1-lithium-2-tert-butyl-1,2-dihydropyridine (1tLi) functions as a precatalyst to convert Me2 NH⋅BH3 to [NMe2 BH2 ]2 (89 % conversion) under competitive conditions (2.5 mol %, 60 h, 80 °C, toluene solvent) to that of previously reported LiN(SiMe3 )2 . Sodium and potassium dihydropyridine congeners produce similar high yields of [NMe2 BH2 ]2 but require longer times. Switching the solvent to pyridine induces a remarkable change in the dehydrocoupling product ratio, with (NMe2 )2 BH favoured over [NMe2 BH2 ]2 (e.g., 94 %:2 % for 1tLi). Demonstrating its versatility, precatalyst 1tLi was also successful in promoting hydroboration reactions between pinacolborane and a selection of aldehydes and ketones. Most reactions gave near quantitative conversion to the hydroborated products in 15 minutes, though sterically demanding carbonyl substrates require longer times. The mechanisms of these rare examples of Group 1 metal-catalysed processes are discussed.
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Affiliation(s)
- Ross McLellan
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Alan R. Kennedy
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Robert E. Mulvey
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Samantha A. Orr
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
| | - Stuart D. Robertson
- WestCHEM, Department of Pure and Applied ChemistryUniversity of StrathclydeGlasgowG1 1XLUK
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83
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Affiliation(s)
- Georgii I. Nikonov
- Department of Chemistry, Brock University, 1812
Sir Isaac Brock Way, St. Catharines, Ontario, Canada L2S 3A1
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84
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Wen H, Zhang L, Zhu S, Liu G, Huang Z. Stereoselective Synthesis of Trisubstituted Alkenes via Cobalt-Catalyzed Double Dehydrogenative Borylations of 1-Alkenes. ACS Catal 2017. [DOI: 10.1021/acscatal.7b02104] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Huanan Wen
- State Key Laboratory of Organometallic
Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Lei Zhang
- State Key Laboratory of Organometallic
Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Suzhen Zhu
- State Key Laboratory of Organometallic
Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Guixia Liu
- State Key Laboratory of Organometallic
Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Zheng Huang
- State Key Laboratory of Organometallic
Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
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85
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86
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Rauser M, Ascheberg C, Niggemann M. Electrophilic Amination with Nitroarenes. Angew Chem Int Ed Engl 2017; 56:11570-11574. [DOI: 10.1002/anie.201705356] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/04/2017] [Indexed: 01/14/2023]
Affiliation(s)
- Marian Rauser
- Institute of Organic Chemistry; RWTH Aachen; Landoltweg 1 52072 Aachen Germany
| | - Christoph Ascheberg
- Institute of Organic Chemistry; RWTH Aachen; Landoltweg 1 52072 Aachen Germany
| | - Meike Niggemann
- Institute of Organic Chemistry; RWTH Aachen; Landoltweg 1 52072 Aachen Germany
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87
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Olechnowicz F, Hillhouse GL, Cundari TR, Jordan RF. Heterolytic H–H and H–B Bond Cleavage Reactions of {(IPr)Ni(μ-S)}2. Inorg Chem 2017; 56:9922-9930. [DOI: 10.1021/acs.inorgchem.7b01420] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Frank Olechnowicz
- Department of Chemistry, The University of Chicago, 5735 S. Ellis Avenue, Chicago, Illinois 60637, United States
| | - Gregory L. Hillhouse
- Department of Chemistry, The University of Chicago, 5735 S. Ellis Avenue, Chicago, Illinois 60637, United States
| | - Thomas R. Cundari
- Department of Chemistry, Center for Advanced
Scientific Computing and Modeling (CASCaM), University of North Texas, P.O. Box
305070, Denton, Texas 76203-5070, United States
| | - Richard F. Jordan
- Department of Chemistry, The University of Chicago, 5735 S. Ellis Avenue, Chicago, Illinois 60637, United States
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88
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Wu D, Wang R, Li Y, Ganguly R, Hirao H, Kinjo R. Electrostatic Catalyst Generated from Diazadiborinine for Carbonyl Reduction. Chem 2017. [DOI: 10.1016/j.chempr.2017.06.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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89
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Affiliation(s)
- Étienne Rochette
- Département de Chimie, Centre de Catalyse et Chimie Verte (C3 V) Université Laval, 1045 Avenue de
la Médecine, Québec, G1V 0A6 Québec, Canada
| | - Hugo Boutin
- Département de Chimie, Centre de Catalyse et Chimie Verte (C3 V) Université Laval, 1045 Avenue de
la Médecine, Québec, G1V 0A6 Québec, Canada
| | - Frédéric-Georges Fontaine
- Département de Chimie, Centre de Catalyse et Chimie Verte (C3 V) Université Laval, 1045 Avenue de
la Médecine, Québec, G1V 0A6 Québec, Canada
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90
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Fawcett A, Pradeilles J, Wang Y, Mutsuga T, Myers EL, Aggarwal VK. Photoinduced decarboxylative borylation of carboxylic acids. Science 2017; 357:283-286. [DOI: 10.1126/science.aan3679] [Citation(s) in RCA: 379] [Impact Index Per Article: 54.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 06/07/2017] [Indexed: 12/30/2022]
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91
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Shoba VM, Takacs JM. Remarkably Facile Borane-Promoted, Rhodium-Catalyzed Asymmetric Hydrogenation of Tri- and Tetrasubstituted Alkenes. J Am Chem Soc 2017; 139:5740-5743. [PMID: 28394591 PMCID: PMC5408738 DOI: 10.1021/jacs.7b02581] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Oxime-directed
catalytic asymmetric hydroboration is diverted to
catalytic asymmetric hydrogenation (CAH) upon the addition of a proton
source, such as MeOH, or by running the reaction under a hydrogen
atmosphere. A borane (e.g., pinacolborane) is required to promote
CAH. Tri- and tetrasubstituted alkenes, including the challenging
all-alkyl tetrasubstituted alkenes, undergo CAH with enantiomer ratios
(er) as high as 99:1. The mild reaction conditions, i.e., ambient
temperature, moderate reaction times, and the need for only a slight
excess of H2, contrast those used in most state-of-the-art
catalysts for related substrates.
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Affiliation(s)
- Veronika M Shoba
- Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588-0304, United States
| | - James M Takacs
- Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588-0304, United States
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92
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Yuan K, Wang S. trans-Aminoboration across Internal Alkynes Catalyzed by B(C6F5)3 for the Synthesis of Borylated Indoles. Org Lett 2017; 19:1462-1465. [DOI: 10.1021/acs.orglett.7b00437] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kang Yuan
- Department
of Chemistry, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Suning Wang
- Department
of Chemistry, Queen’s University, Kingston, Ontario K7L 3N6, Canada
- Beijing
Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials,
School of Chemistry, Beijing Institute of Technology, Beijing 100081, P. R. China
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93
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Romero EA, Olsen PM, Jazzar R, Soleilhavoup M, Gembicky M, Bertrand G. Spectroscopic Evidence for a Monomeric Copper(I) Hydride and Crystallographic Characterization of a Monomeric Silver(I) Hydride. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201700858] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Erik A. Romero
- Joint UCSD-CNRS Research Chemistry Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego La Jolla CA 92093-0358 USA
| | - Pauline M. Olsen
- Joint UCSD-CNRS Research Chemistry Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego La Jolla CA 92093-0358 USA
| | - Rodolphe Jazzar
- Joint UCSD-CNRS Research Chemistry Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego La Jolla CA 92093-0358 USA
| | - Michele Soleilhavoup
- Joint UCSD-CNRS Research Chemistry Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego La Jolla CA 92093-0358 USA
| | - Milan Gembicky
- UCSD Crystallography Facility Department of Chemistry and Biochemistry Urey Hall Room 5128 9500 Gilman Drive, M/C 0358 La Jolla CA 92093-0358 USA
| | - Guy Bertrand
- Joint UCSD-CNRS Research Chemistry Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego La Jolla CA 92093-0358 USA
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94
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Romero EA, Olsen PM, Jazzar R, Soleilhavoup M, Gembicky M, Bertrand G. Spectroscopic Evidence for a Monomeric Copper(I) Hydride and Crystallographic Characterization of a Monomeric Silver(I) Hydride. Angew Chem Int Ed Engl 2017; 56:4024-4027. [DOI: 10.1002/anie.201700858] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Indexed: 01/25/2023]
Affiliation(s)
- Erik A. Romero
- Joint UCSD-CNRS Research Chemistry Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego La Jolla CA 92093-0358 USA
| | - Pauline M. Olsen
- Joint UCSD-CNRS Research Chemistry Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego La Jolla CA 92093-0358 USA
| | - Rodolphe Jazzar
- Joint UCSD-CNRS Research Chemistry Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego La Jolla CA 92093-0358 USA
| | - Michele Soleilhavoup
- Joint UCSD-CNRS Research Chemistry Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego La Jolla CA 92093-0358 USA
| | - Milan Gembicky
- UCSD Crystallography Facility Department of Chemistry and Biochemistry Urey Hall Room 5128 9500 Gilman Drive, M/C 0358 La Jolla CA 92093-0358 USA
| | - Guy Bertrand
- Joint UCSD-CNRS Research Chemistry Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California San Diego La Jolla CA 92093-0358 USA
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95
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Competition of van der Waals and chemical forces on gold–sulfur surfaces and nanoparticles. Nat Rev Chem 2017. [DOI: 10.1038/s41570-017-0017] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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96
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Adams MR, Tien CH, Huchenski BSN, Ferguson MJ, Speed AWH. Diazaphospholene Precatalysts for Imine and Conjugate Reductions. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611570] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Matt R. Adams
- Department of Chemistry; Dalhousie University; Halifax Nova Scotia B3H 4R2 Canada
| | - Chieh-Hung Tien
- Department of Chemistry; Dalhousie University; Halifax Nova Scotia B3H 4R2 Canada
| | | | - Michael J. Ferguson
- X-ray Crystallography Laboratory; Department of Chemistry, University of Alberta; Edmonton Alberta T6G 2G2 Canada
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97
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Diazaphospholene Precatalysts for Imine and Conjugate Reductions. Angew Chem Int Ed Engl 2017; 56:6268-6271. [DOI: 10.1002/anie.201611570] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Indexed: 01/03/2023]
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98
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Xu D, Shan C, Li Y, Qi X, Luo X, Bai R, Lan Y. Bond dissociation energy controlled σ-bond metathesis in alkaline-earth-metal hydride catalyzed dehydrocoupling of amines and boranes: a theoretical study. Inorg Chem Front 2017. [DOI: 10.1039/c7qi00459a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Alkaline-earth-metal could catalyse the dehydrocoupling procedure of N–H and B–H bond due to the low Ae–H bond energy. The direct σ-bond metathesis procedure is proved to be unfavourable.
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Affiliation(s)
- Dongdong Xu
- School of Chemistry and Chemical Engineering
- Chongqing University
- Chongqing 400044
- P. R. China
| | - Chunhui Shan
- School of Chemistry and Chemical Engineering
- Chongqing University
- Chongqing 400044
- P. R. China
| | - Yingzi Li
- School of Chemistry and Chemical Engineering
- Chongqing University
- Chongqing 400044
- P. R. China
| | - Xiaotian Qi
- School of Chemistry and Chemical Engineering
- Chongqing University
- Chongqing 400044
- P. R. China
| | - Xiaoling Luo
- College of Chemistry
- Chongqing Normal University
- Chongqing 401331
- P. R. China
| | - Ruopeng Bai
- School of Chemistry and Chemical Engineering
- Chongqing University
- Chongqing 400044
- P. R. China
| | - Yu Lan
- School of Chemistry and Chemical Engineering
- Chongqing University
- Chongqing 400044
- P. R. China
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99
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Erickson JD, Lai TY, Liptrot DJ, Olmstead MM, Power PP. Catalytic dehydrocoupling of amines and boranes by an incipient tin(ii) hydride. Chem Commun (Camb) 2016; 52:13656-13659. [DOI: 10.1039/c6cc06963k] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
{ArMe6Sn(μ-OMe)}2 (1, ArMe6 = C6H3-2,6-(C6H2-2,4,6-Me3)2) and {AriPr4Sn(μ-OMe)}2 (2, AriPr4 = C6H3-2,6-(C6H3-2,6-iPr2)2) facilitate the dehydrocoupling of ammonia, 1° and 2° amines with HBpin. 2 catalyzes the reactions faster than 1 but is limited to 1° amines. Synthesis and characterization of a tin(ii) amide and amide-hydride give insight into the catalytic mechanism.
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Affiliation(s)
| | - Ting Yi Lai
- Department of Chemistry
- University of California
- Davis
- USA
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100
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Abstract
David Craig (1919–2015) left us with a lasting legacy concerning basic understanding of chemical spectroscopy and bonding. This is expressed in terms of some of the recent achievements of my own research career, with a focus on integration of Craig’s theories with those of Noel Hush to solve fundamental problems in photosynthesis, molecular electronics (particularly in regard to the molecules synthesized by Maxwell Crossley), and self-assembled monolayer structure and function. Reviewed in particular is the relation of Craig’s legacy to: the 50-year struggle to assign the visible absorption spectrum of arguably the world’s most significant chromophore, chlorophyll; general theories for chemical bonding and structure extending Hush’s adiabatic theory of electron-transfer processes; inelastic electron-tunnelling spectroscopy (IETS); chemical quantum entanglement and the Penrose–Hameroff model for quantum consciousness; synthetic design strategies for NMR quantum computing; Gibbs free-energy measurements and calculations for formation and polymorphism of organic self-assembled monolayers on graphite surfaces from organic solution; and understanding the basic chemical processes involved in the formation of gold surfaces and nanoparticles protected by sulfur-bound ligands, ligands whose form is that of Au0-thiyl rather than its commonly believed AuI-thiolate tautomer.
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