1
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Calogero F, Magagnano G, Potenti S, Pasca F, Fermi A, Gualandi A, Ceroni P, Bergamini G, Cozzi PG. Diastereoselective and enantioselective photoredox pinacol coupling promoted by titanium complexes with a red-absorbing organic dye. Chem Sci 2022; 13:5973-5981. [PMID: 35685797 PMCID: PMC9132033 DOI: 10.1039/d2sc00800a] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 04/21/2022] [Indexed: 12/12/2022] Open
Abstract
The pinacol coupling reaction, a reductive coupling of carbonyl compounds that proceeds through the formation of ketyl radicals in the presence of an electron donor, affords the corresponding 1,2-diols in one single step. The photoredox version of this transformation has been accomplished using different organic dyes or photoactive metal complexes in the presence of sacrificial donors such as tertiary amines or Hantzsch's ester. Normally, the homo-coupling of such reactive ketyl radicals is neither diastereo- nor enantio-selective. Herein, we report a highly diastereoselective pinacol coupling reaction of aromatic aldehydes promoted by 5 mol% of the non-toxic, inexpensive and available Cp2TiCl2 complex. The key feature that allows the complete control of diastereoselectivity is the employment of a red-absorbing organic dye in the presence of a redox-active titanium complex. Taking advantage of the well-tailored photoredox potential of this organic dye, the selective reduction of Ti(iv) to Ti(iii) is achieved. These conditions enable the formation of the d,l (syn) diastereoisomer as the favored product of the pinacol coupling (d.r. > 20 : 1 in most of the cases). Moreover, employing a simply prepared chiral SalenTi complex, the new photoredox reaction gave a complete diastereoselection for the d,l diastereoisomer, and high enantiocontrol (up to 92% of enantiomeric excess). A metallaphotoredox, diastereoselective and enantioselective pinacol coupling reaction promoted by titanium complexes with the use of a red-absorbing organic dye was developed.![]()
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Affiliation(s)
- Francesco Calogero
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Giandomenico Magagnano
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Simone Potenti
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy .,Laboratorio SMART, Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa Italy
| | - Francesco Pasca
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Andrea Fermi
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy .,Center for Chemical Catalysis - C3, Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Andrea Gualandi
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy .,Center for Chemical Catalysis - C3, Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Paola Ceroni
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy .,Center for Chemical Catalysis - C3, Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Giacomo Bergamini
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Pier Giorgio Cozzi
- Dipartimento di Chimica "Giacomo Ciamician", Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy .,Center for Chemical Catalysis - C3, Alma Mater Studiorum - Università di Bologna Via Selmi 2 40126 Bologna Italy
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2
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Jensen JD, Bisballe N, Kacenauskaite L, Thomsen MS, Chen J, Hammerich O, Laursen BW. Utilizing Selective Chlorination to Synthesize New Triangulenium Dyes. J Org Chem 2021; 86:17002-17010. [PMID: 34791879 DOI: 10.1021/acs.joc.1c02148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Functionalization of new sites on the triangulenium structure has been achieved by early-stage chlorination with N-chlorosuccinimide (NCS), giving rise to two new triangulenium dyes (1 and 3). By introducing the chlorine functionalities in the acridinium precursor, positions complementary to those previously obtained by electrophilic aromatic substitution on the final dyes are accessed. The chlorination is selective, giving only one regioisomer for both mono- and dichlorination products. For the monochlorinated acridinium compound, a highly selective ring-closing reaction was discovered, generating a single regioisomer of the cationic [4]helicene product. Further investigations into the mechanism of the [4]helicene formation lead to the first isolation of the previously proposed intermediate of the two-step SNAr reaction, key to all aza-bridged triangulenium and helicenium systems. Late-stage functionalization of DAOTA+ with NCS gave rise to a different dichlorinated compound (2). The fully ring closed chlorinated triangulenium dyes 1, 2, and 3 show a redshift in absorption and emission, while maintaining relatively high fluorescence quantum yields of 36%, 26%, and 41% and long fluorescence lifetimes of 15, 12.5, and 16 ns, respectively. Cyclic voltammetry shows that chlorination of the triangulenium dyes significantly lowers reduction potentials and thus allows for efficient tuning of redox and photoredox properties.
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Affiliation(s)
- Jesper Dahl Jensen
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Niels Bisballe
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Laura Kacenauskaite
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Maria Storm Thomsen
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Junsheng Chen
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Ole Hammerich
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Bo W Laursen
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
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3
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Gianetti T, Mei L. Helical Carbenium Ion-Based Organic Photoredox Catalyst: A Versatile and Sustainable Option in Red-Light-Induced Reactions. Synlett 2020. [DOI: 10.1055/s-0040-1705942] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
AbstractThe development of a sustainable catalytic system for red-light-induced photocatalysis is presented. The catalytic system consists of a helical carbenium ion-based organic photoredox catalyst (PC) that is capable of using low-energy red light (λmax = 640 nm) for both photooxidations and photoreductions. Its successful applications in the aerobic oxidative hydroxylation of arylboronic acids and in the oxidation of benzylic C(sp3)–H bonds (reductive quenching), as well as in dual transition-metal/organocatalyzed C–H arylations and intermolecular atom-transfer radical additions (oxidative quenching) provide further support for its role as a versatile and efficient organic PC.1 Introduction2 Red-Light-Induced Photocatalysis3 Properties of N,N′-Dipropyl-1,13-dimethoxyquinacridinium Tetrafluoroborate4 Two Proposed Representative Catalytic Cycles of [
n
Pr-DMQA+][BF4
–]5 Applications of [
n
Pr-DMQA+][BF4
–] in Red-Light-Induced Photocatalysis6 Conclusion
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Affiliation(s)
- Thomas Gianetti
- Department of Chemistry and Biochemistry, University of Arizona
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4
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Mei L, Veleta JM, Gianetti TL. Helical Carbenium Ion: A Versatile Organic Photoredox Catalyst for Red-Light-Mediated Reactions. J Am Chem Soc 2020; 142:12056-12061. [DOI: 10.1021/jacs.0c05507] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Liangyong Mei
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - José M. Veleta
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Thomas L. Gianetti
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
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5
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Ghosh S, Jana CK. Metal free biomimetic deaminative direct C-C coupling of unprotected primary amines with active methylene compounds. Org Biomol Chem 2019; 17:10153-10157. [PMID: 31774427 DOI: 10.1039/c9ob02163a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
An unprecedented direct C-C coupling reaction of unprotected primary amines with active methylene compounds is reported. The reaction involves a biomimetic deamination of amines which was achieved under conditions free of metallic reagents and strong oxidizing agents. A wide range of primary amines was reacted with different active methylene compounds to provide structurally diverse trisubstituted alkenes and dihydropyridines. A kinetic study revealed an activation barrier of 10.1 kcal mol-1 for the conversion of a key intermediate of the reaction.
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Affiliation(s)
- Santanu Ghosh
- Department of Chemistry, Indian Institute of Technology Guwahati, 780139, India.
| | - Chandan K Jana
- Department of Chemistry, Indian Institute of Technology Guwahati, 780139, India.
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6
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Labrador GM, Besnard C, Bürgi T, Poblador-Bahamonde AI, Bosson J, Lacour J. Stereochemical significance of O to N atom interchanges within cationic helicenes: experimental and computational evidence of near racemization to remarkable enantiospecificity. Chem Sci 2019; 10:7059-7067. [PMID: 31588273 PMCID: PMC6676467 DOI: 10.1039/c9sc02127b] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 06/11/2019] [Indexed: 11/21/2022] Open
Abstract
Oxygen atoms of cationic dioxa and azaoxa [6]helicenes can be exchanged by amino groups to form azaoxa and diaza [6]helicenes respectively. The mild reaction conditions developed herein allow the construction of libraries of derivatives with sensitive and/or functionalized side chains. Using enantioenriched dioxa or azaoxa helicene precursors, these exchanges lead to either near racemization (es 3%) or to a remarkable enantiospecificity (es up to 97%). This unusual behavior is fully characterized via experimental and computational mechanistic evidence. Based on these investigations, the enantiospecificity of the first transformation can be improved to 57-61%.
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Affiliation(s)
| | - Céline Besnard
- Laboratory of Crystallography , University of Geneva , Switzerland
| | - Thomas Bürgi
- Department of Physical Chemistry , University of Geneva , Switzerland
| | | | - Johann Bosson
- Department of Organic Chemistry , University of Geneva , Switzerland . ; ;
| | - Jérôme Lacour
- Department of Organic Chemistry , University of Geneva , Switzerland . ; ;
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7
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Ni S, El Remaily MAEAAA, Franzén J. Carbocation Catalyzed Bromination of Alkyl Arenes, a Chemoselective
sp
3
vs. sp
2
C−H functionalization. Adv Synth Catal 2018. [DOI: 10.1002/adsc.201800788] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Shengjun Ni
- KTH, Royal Institute of TechnologySchool of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Chemistry/Division of Organic Chemistry Teknikringen 30 SE-100 44 Stockholm Sweden
| | - Mahmoud Abd El Aleem Ali Ali El Remaily
- KTH, Royal Institute of TechnologySchool of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Chemistry/Division of Organic Chemistry Teknikringen 30 SE-100 44 Stockholm Sweden
- Department of Chemistry, Faculty of ScienceSohag University 82524 Sohag Egypt
| | - Johan Franzén
- KTH, Royal Institute of TechnologySchool of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Chemistry/Division of Organic Chemistry Teknikringen 30 SE-100 44 Stockholm Sweden
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8
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Ni S, Franzén J. Carbocation catalysed ring closing aldehyde–olefin metathesis. Chem Commun (Camb) 2018; 54:12982-12985. [DOI: 10.1039/c8cc06734a] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
4-Phenylphenyl-diphenylmethylium tetrafluoroborate catalyses a rare high yielding intramolecular aldehyde–olefin metathesis of enals under mild reaction conditions and low catalyst loading.
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Affiliation(s)
- Shengjun Ni
- Department of Chemistry
- Organic Chemistry
- Royal Institute of Technology (KTH)
- SE-100 44 Stockholm
- Sweden
| | - Johan Franzén
- Department of Chemistry
- Organic Chemistry
- Royal Institute of Technology (KTH)
- SE-100 44 Stockholm
- Sweden
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9
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Bonesi SM, Protti S, Albini A. Reactive Oxygen Species (ROS)-vs Peroxyl-Mediated Photosensitized Oxidation of Triphenylphosphine: A Comparative Study. J Org Chem 2016; 81:11678-11685. [DOI: 10.1021/acs.joc.6b02088] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sergio Mauricio Bonesi
- Departamento
de Química Orgánica, CIHIDECAR − CONICET, 3er Piso, Pabellón 2, Ciudad Universitaria, FCEyN, University of Buenos Aires, Buenos Aires 1428, Argentina
- Department
of Chemistry, PhotoGreen Lab, V.Le Taramelli 12, 27100 Pavia, Italy
| | - Stefano Protti
- Department
of Chemistry, PhotoGreen Lab, V.Le Taramelli 12, 27100 Pavia, Italy
| | - Angelo Albini
- Department
of Chemistry, PhotoGreen Lab, V.Le Taramelli 12, 27100 Pavia, Italy
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10
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Stępień M, Gońka E, Żyła M, Sprutta N. Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds: Synthetic Routes, Properties, and Applications. Chem Rev 2016; 117:3479-3716. [PMID: 27258218 DOI: 10.1021/acs.chemrev.6b00076] [Citation(s) in RCA: 851] [Impact Index Per Article: 106.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Two-dimensionally extended, polycyclic heteroaromatic molecules (heterocyclic nanographenes) are a highly versatile class of organic materials, applicable as functional chromophores and organic semiconductors. In this Review, we discuss the rich chemistry of large heteroaromatics, focusing on their synthesis, electronic properties, and applications in materials science. This Review summarizes the historical development and current state of the art in this rapidly expanding field of research, which has become one of the key exploration areas of modern heterocyclic chemistry.
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Affiliation(s)
- Marcin Stępień
- Wydział Chemii, Uniwersytet Wrocławski , ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Elżbieta Gońka
- Wydział Chemii, Uniwersytet Wrocławski , ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Marika Żyła
- Wydział Chemii, Uniwersytet Wrocławski , ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Natasza Sprutta
- Wydział Chemii, Uniwersytet Wrocławski , ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland
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11
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Ni S, Ramesh Naidu V, Franzén J. Chiral Anion Directed Asymmetric Carbocation-Catalyzed Diels-Alder Reactions. European J Org Chem 2016. [DOI: 10.1002/ejoc.201501621] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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12
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Noguchi H, Hirose T, Yokoyama S, Matsuda K. Fluorescence behavior of 2,6,10-trisubstituted 4,8,12-triazatriangulene cations in solution and in the solid state. CrystEngComm 2016. [DOI: 10.1039/c6ce00703a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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13
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Yokoyama S, Hirose T, Matsuda K. Photochemical Cleavage of Axial Group Attached to the Central Carbon Atom of Triangulene Leuco Derivatives at the Ethanol/Au(111) Substrate. CHEM LETT 2015. [DOI: 10.1246/cl.150738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Soichi Yokoyama
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University
| | - Takashi Hirose
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University
| | - Kenji Matsuda
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University
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14
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15
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Wallabregue A, Sherin P, Guin J, Besnard C, Vauthey E, Lacour J. Modular Synthesis of pH-Sensitive Fluorescent Diaza[4]helicenes. European J Org Chem 2014. [DOI: 10.1002/ejoc.201402863] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Gouin J, Bürgi T, Guénée L, Lacour J. Convergent synthesis, resolution, and chiroptical properties of dimethoxychromenoacridinium ions. Org Lett 2014; 16:3800-3. [PMID: 24999966 DOI: 10.1021/ol501692r] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Cationic azaoxa[4]helicenes can be prepared in a single step from a common xanthenium precursor by addition of nucleophilic amines under monitored conditions (160 °C, 2 min, MW). The (-)-(M) and (+)-(P) enantiomers can be separated by chiral stationary-phase chromatography. Determination of the absolute configuration and racemization barrier (ΔG(⧧) (433 K) 33.3 ± 1.3 kcal·mol(-1)) was achieved by VCD and ECD spectroscopy, respectively.
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Affiliation(s)
- Jérôme Gouin
- Department of Organic Chemistry, ‡Department of Physical Chemistry, and §Laboratory of Crystallography, University of Geneva , Quai Ernest Ansermet 30, CH-1211 Geneva 4, Switzerland
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17
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Bosson J, Gouin J, Lacour J. Cationic triangulenes and helicenes: synthesis, chemical stability, optical properties and extended applications of these unusual dyes. Chem Soc Rev 2014; 43:2824-40. [PMID: 24500211 DOI: 10.1039/c3cs60461f] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cationic triangulenes and helicenes are highly stable carbocations with planar and helical conformations respectively. These moieties are effective dyes with original absorption and emission properties. Over the last decade, they have received greater attention and are considered as valuable tools for the development of innovative applications. In this review, the synthesis of these unique compounds is presented together with their core chemical and physical properties. Representative applications spanning from surface sciences to biology and chemistry are presented.
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Affiliation(s)
- Johann Bosson
- Department of Organic Chemistry, University of Geneva, quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
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18
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Opriş CM, Pavel OD, Moragues A, El Haskourib J, Beltrán D, Amorós P, Marcos MD, Stoflea LE, Parvulescu VI. New multicomponent catalysts for the selective aerobic oxidative condensation of benzylamine to N-benzylidenebenzylamine. Catal Sci Technol 2014. [DOI: 10.1039/c4cy00795f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nano-oxide domains partially embedded inside the UVM-7 silica walls act as excellent support for Au in the oxidative condensation of benzylamine.
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Affiliation(s)
- C. M. Opriş
- Department of Organic Chemistry and Catalysis
- University of Bucharest
- 030016 Bucharest, Romania
| | - O. D. Pavel
- Department of Organic Chemistry and Catalysis
- University of Bucharest
- 030016 Bucharest, Romania
| | - A. Moragues
- Institut de Ciencia dels Material
- Universitat de Valencia
- Valencia E46071, Spain
| | - J. El Haskourib
- Fundació General
- Universitat de Valencia
- Valencia E46071, Spain
| | - D. Beltrán
- Institut de Ciencia dels Material
- Universitat de Valencia
- Valencia E46071, Spain
| | - P. Amorós
- Institut de Ciencia dels Material
- Universitat de Valencia
- Valencia E46071, Spain
| | - M. D. Marcos
- Centro de Reconocimiento Molecular y Desarrollo Tecnológico (IDM)
- Departamento de Química
- Universidad Politécnica de Valencia
- 46022-Valencia, Spain
| | - L. E. Stoflea
- National Institute of Materials Physics
- 077125 Bucharest-Magurele, Romania
| | - V. I. Parvulescu
- Department of Organic Chemistry and Catalysis
- University of Bucharest
- 030016 Bucharest, Romania
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19
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Abstract
Abstract The term Lewis acid catalysts generally refers to metal salts like aluminium chloride, titanium chloride and zinc chloride. Their application in asymmetric catalysis can be achieved by the addition of enantiopure ligands to these salts. However, not only metal centers can function as Lewis acids. Compounds containing carbenium, silyl or phosphonium cations display Lewis acid catalytic activity. In addition, hypervalent compounds based on phosphorus and silicon, inherit Lewis acidity. Furthermore, ionic liquids, organic salts with a melting point below 100 degrees C, have revealed the ability to catalyze a range of reactions either in substoichiometric amount or, if used as the reaction medium, in stoichiometric or even larger quantities. The ionic liquids can often be efficiently recovered. The catalytic activity of the ionic liquid is explained by the Lewis acidic nature of their cations. This review covers the survey of known classes of metal-free Lewis acids and their application in catalysis.
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Affiliation(s)
- Oksana Sereda
- Clausthal University of Technology, Leibnizstr. 6, 38678 Clausthal-Zellerfeld, Germany
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20
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Lang X, Ji H, Chen C, Ma W, Zhao J. Selective Formation of Imines by Aerobic Photocatalytic Oxidation of Amines on TiO2. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201007056] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Lang X, Ji H, Chen C, Ma W, Zhao J. Selective Formation of Imines by Aerobic Photocatalytic Oxidation of Amines on TiO2. Angew Chem Int Ed Engl 2011; 50:3934-7. [DOI: 10.1002/anie.201007056] [Citation(s) in RCA: 364] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 01/17/2011] [Indexed: 11/10/2022]
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22
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Nicolas C, Bernardinelli G, Lacour J. On the synthesis and optical properties of sulfur-bridged analogues of triangulenium cations and their precursors. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1753] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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23
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Berlicka A, König B. Porphycene-mediated photooxidation of benzylamines by visible light. Photochem Photobiol Sci 2010; 9:1359-66. [PMID: 20820677 DOI: 10.1039/c0pp00192a] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A variety of primary and secondary benzylic amines were oxidized efficiently to N-benzylidenebenzylamines and imines, respectively, using 2,7,12,17-tetrapropylporphycene (H(2)TPrPc) photocatalyst and blue light emitting diodes (LEDs). The photooxidation of 4-methoxybenzylamine in the presence of H(2)TPrPc and its tin(IV) complex Sn(TPrPc)Cl(2) was studied in detail in order to show that operating mechanisms can be different depending on the photosensitizer type. Two experiments involving solvent deuterium isotope effect and competitive quenching with DABCO provide evidence for the singlet oxygen mechanism as the major pathway in the H(2)TPrPc-catalyzed reaction and the predominance of the direct electron transfer from the photoexcited dye to the amine when the Sn(TPrPc)Cl(2) complex was used as a photocatalyst.
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Affiliation(s)
- Anna Berlicka
- Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, 93040, Regensburg, Germany
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24
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Guin J, Besnard C, Lacour J. Synthesis, Resolution, and Stabilities of a Cationic Chromenoxanthene [4]helicene. Org Lett 2010; 12:1748-51. [DOI: 10.1021/ol1003466] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Joyram Guin
- Department of Organic Chemistry, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland, and Laboratory of Crystallography, University of Geneva, quai Ernest Ansermet 24, CH-1211 Genève 4, Switzerland
| | - Céline Besnard
- Department of Organic Chemistry, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland, and Laboratory of Crystallography, University of Geneva, quai Ernest Ansermet 24, CH-1211 Genève 4, Switzerland
| | - Jérôme Lacour
- Department of Organic Chemistry, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland, and Laboratory of Crystallography, University of Geneva, quai Ernest Ansermet 24, CH-1211 Genève 4, Switzerland
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25
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Denekamp C, Lacour J, Laleu B, Rabkin E. Tris(2,4,6-trimethoxyphenyl)methyl carbenium ion for charge derivatization of amines and amino acids. JOURNAL OF MASS SPECTROMETRY : JMS 2008; 43:623-627. [PMID: 18078301 DOI: 10.1002/jms.1360] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Primary and secondary alkyl amines substitute readily one of the para-methoxy substituents of tris(2,4,6-trimethoxyphenyl)methyl carbenium ion. With this rapid process, the preparation of permanently charged positive derivatives of amines, amino acids and small C-protected peptides is achieved. This is utilized here to facilitate the matrix assisted laser desorption ionization-time-of-flight (MALDI-TOF) analysis of these compounds.
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Affiliation(s)
- Chagit Denekamp
- Department of Chemistry, Technion Israel Institute of Technology, Haifa, Israel.
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26
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Mobian P, Nicolas C, Francotte E, Bürgi T, Lacour J. Synthesis, Resolution, and VCD Analysis of an Enantiopure Diazaoxatricornan Derivative. J Am Chem Soc 2008; 130:6507-14. [DOI: 10.1021/ja800262j] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pierre Mobian
- Department of Organic Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland, Global Discovery Chemistry, Novartis Institutes for Biomedical Research, WKL-122.P.25 Postfach, CH-4002 Basel, Switzerland, and Institute of Microtechnology, University of Neuchâtel, 11, Rue Emile-Argand, 158 Postfach, CH-2009 Neuchâtel, Switzerland
| | - Cyril Nicolas
- Department of Organic Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland, Global Discovery Chemistry, Novartis Institutes for Biomedical Research, WKL-122.P.25 Postfach, CH-4002 Basel, Switzerland, and Institute of Microtechnology, University of Neuchâtel, 11, Rue Emile-Argand, 158 Postfach, CH-2009 Neuchâtel, Switzerland
| | - Eric Francotte
- Department of Organic Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland, Global Discovery Chemistry, Novartis Institutes for Biomedical Research, WKL-122.P.25 Postfach, CH-4002 Basel, Switzerland, and Institute of Microtechnology, University of Neuchâtel, 11, Rue Emile-Argand, 158 Postfach, CH-2009 Neuchâtel, Switzerland
| | - Thomas Bürgi
- Department of Organic Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland, Global Discovery Chemistry, Novartis Institutes for Biomedical Research, WKL-122.P.25 Postfach, CH-4002 Basel, Switzerland, and Institute of Microtechnology, University of Neuchâtel, 11, Rue Emile-Argand, 158 Postfach, CH-2009 Neuchâtel, Switzerland
| | - Jérôme Lacour
- Department of Organic Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland, Global Discovery Chemistry, Novartis Institutes for Biomedical Research, WKL-122.P.25 Postfach, CH-4002 Basel, Switzerland, and Institute of Microtechnology, University of Neuchâtel, 11, Rue Emile-Argand, 158 Postfach, CH-2009 Neuchâtel, Switzerland
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