1
|
Pradhan TR, Kyoon Park J. Chemoselective Coupling of π-Systems to Access Metallated 1,4- or 1,5-Skipped Dienes in Multicomponent Reactions. Chemistry 2022; 28:e202202120. [PMID: 36094297 DOI: 10.1002/chem.202202120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Indexed: 12/14/2022]
Abstract
Integrating distinct unsaturated C-C systems while simultaneously installing metallic groups has been significantly challenging to execute in a multicomponent reaction. Therefore, designing a suitable mechanistic pathway that provides the required reactivity and selectivity for target C-C bonds with metallic reagents to ensure successful coupling is the key to success. Copper-catalyzed borylallylation and silylallylation have emerged as the most efficient strategies for assembling borylated/silylated skipped (1,4 or 1,5) dienes by catalytically combining an organocopper intermediate with allyl electrophiles. However, reactions involving interelemental reagents (e. g., [Si]-[B]) to accomplish intermolecular atom-economic couplings have not been studied thoroughly. Therefore, to aid the development of new transformations in this research area, this article attempts to include all precedents, including recent studies by the authors. The present Concept article may be helpful for researchers working in this area as it provides a basic conceptual framework.
Collapse
Affiliation(s)
- Tapas R Pradhan
- Department of Chemistry, Chemistry Institute for Functional Materials, Pusan National University, 46241, Busan, Korea
| | - Jin Kyoon Park
- Department of Chemistry, Chemistry Institute for Functional Materials, Pusan National University, 46241, Busan, Korea
| |
Collapse
|
2
|
Averdunk A, Hasenbeck M, Müller T, Becker J, Gellrich U. 1,2-Carboboration of Arylallenes by In Situ Generated Alkenylboranes for the Synthesis of 1,4-Dienes. Chemistry 2022; 28:e202200470. [PMID: 35348257 PMCID: PMC9325554 DOI: 10.1002/chem.202200470] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Indexed: 12/26/2022]
Abstract
We herein report a novel method for the coupling of unactivated alkynes and arylallenes, which relies on an unprecedented and regioselective 1,2-carboboration of the allene by an alkenylborane. The alkenylborane is conveniently prepared in situ by hydroboration of an alkyne with Piers' borane, i. e., HB(C6 F5 )2 . The boryl-substituted 1,4-dienes that are formed by this carboboration are well-suited for a subsequent Suzuki-Miyaura coupling with aryl iodides. This allowed us to develop a three-step, one-pot protocol for the synthesis of aryl-substituted 1,4-dienes. The generality of the reaction was demonstrated by the synthesis of twenty dienes with modular variations of all three reaction partners. The mechanism of the new 1,2-carboboration was investigated using dispersion corrected double-hybrid DFT computations that allowed us to rationalize the chemo- and regioselectivity of this key step.
Collapse
Affiliation(s)
- Arthur Averdunk
- Institut für Organische ChemieJustus-Liebig-Universität GießenHeinrich-Buff-Ring 1735392GießenGermany
| | - Max Hasenbeck
- Institut für Organische ChemieJustus-Liebig-Universität GießenHeinrich-Buff-Ring 1735392GießenGermany
| | - Tizian Müller
- Institut für Organische ChemieJustus-Liebig-Universität GießenHeinrich-Buff-Ring 1735392GießenGermany
| | - Jonathan Becker
- Institut für Anorganische und Analytische ChemieJustus-Liebig-Universität GießenHeinrich-Buff-Ring 1735392GießenGermany
| | - Urs Gellrich
- Institut für Organische ChemieJustus-Liebig-Universität GießenHeinrich-Buff-Ring 1735392GießenGermany
| |
Collapse
|
3
|
Chen C, Daniliuc CG, Kehr G, Erker G. N-Heterocyclic Carbene Stabilized 1-Bora-1,3-butadienes. J Am Chem Soc 2021; 143:21312-21320. [PMID: 34894685 DOI: 10.1021/jacs.1c09774] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Deprotonation of [(NHC)(Fmes)B-allyl]+ borenium cations (NHC, IMes (a) or IMe2 (b); Fmes, 2,4,6-(CF3)3C6H2) provides an easy entry to the NHC-stabilized 1-bora-1,3-butadienes. They feature a planar s-trans-conformation just like 1,3-butadiene. The 1-borabutadiene 7a undergoes hydroboration reactions; the HB(C6F5)2 hydroboration product is trapped with CO or an isonitrile to give the respective cyclic zwitterionic borenium-borate enolate or enamide products. 1-Borabutadiene 7b undergoes 1,4-chalcogenation with elemental sulfur or selenium, and it gives the six-membered heterocyclic 1,4-addition product with the S═O bond of sulfur dioxide. Compound 7b served as a precursor for the formation of a borylated η3-allyl ligand at Ru. 7b formed a Rh complex by reaction with [Rh(ethylene)2Cl]2. It subsequently underwent an intramolecular C-H activation reaction to a mixture of η3-methyl-boraallyl Rh complex isomers.
Collapse
Affiliation(s)
- Chaohuang Chen
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| |
Collapse
|
4
|
Zorba L, Egaña E, Gómez-Bengoa E, Vougioukalakis GC. Zinc Iodide Catalyzed Synthesis of Trisubstituted Allenes from Terminal Alkynes and Ketones. ACS OMEGA 2021; 6:23329-23346. [PMID: 34549133 PMCID: PMC8444324 DOI: 10.1021/acsomega.1c03092] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 07/13/2021] [Indexed: 05/03/2023]
Abstract
A straightforward, user-friendly, efficient protocol for the one pot, ZnI2-catalyzed allenylation of terminal alkynes with pyrrolidine and ketones, toward trisubstituted allenes, is described. Trisubstituted allenes can be obtained under either conventional heating or microwave irradiation conditions, which significantly reduces the reaction time. A sustainable, widely available, and low-cost metal salt catalyst is employed, and the reactions are carried out under solvent-free conditions. Among others, synthetically valuable allenes bearing functionalities such as amide, hydroxyl, or phthalimide can be efficiently prepared. Mechanistic experiments, including kinetic isotope effect measurements and density functional theory (DFT) calculations, suggest a rate-determining [1,5]-hydride transfer during the transformation of the intermediate propargylamine to the final allene.
Collapse
Affiliation(s)
- Leandros
P. Zorba
- Laboratory
of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771 Athens, Greece
| | - Eunate Egaña
- Department
of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain
| | - Enrique Gómez-Bengoa
- Department
of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain
| | - Georgios C. Vougioukalakis
- Laboratory
of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771 Athens, Greece
| |
Collapse
|
5
|
Hasenbeck M, Wech F, Averdunk A, Becker J, Gellrich U. Indene formation upon borane-induced cyclization of arylallenes, 1,1-carboboration, and retro-hydroboration. Chem Commun (Camb) 2021; 57:5518-5521. [PMID: 33955432 DOI: 10.1039/d1cc01750k] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
We herein report the reaction of arylallenes with tris(pentafluorophenyl)borane that yields pentafluorophenyl substituted indenes. The tris(pentafluorophenyl)borane induces the cyclization of the allene and transfers a pentafluorophenyl ring in the course of this reaction. A Hammett plot analysis and DFT computations indicate a 1,1-carboboration to be the C-C bond-forming step.
Collapse
Affiliation(s)
- Max Hasenbeck
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392 Gießen, Germany.
| | - Felix Wech
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392 Gießen, Germany.
| | - Arthur Averdunk
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392 Gießen, Germany.
| | - Jonathan Becker
- Institut für Analytische und Anorganische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, Gießen 35392, Germany
| | - Urs Gellrich
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392 Gießen, Germany.
| |
Collapse
|
6
|
Zhao Y, Ge S. Chromium-Catalyzed Selective Dimerization/Hydroboration of Allenes to Access Boryl-Functionalized Skipped (E,Z)-Dienes. Angew Chem Int Ed Engl 2021; 60:2149-2154. [PMID: 33027539 DOI: 10.1002/anie.202012344] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Indexed: 11/10/2022]
Abstract
A chromium-catalyzed dimerization/hydroboration of allenes is developed to access synthetically versatile boryl-functionalized skipped dienes with a catalyst generated in situ from CrCl2 and a pyridine-2,6-diimine ligand mes PDI. A variety of allenes reacted with pinacolborane (HBpin) to afford the corresponding boryl-functionalized (E,Z)-1,4-dienes in high yields and with excellent selectivity. Electron paramagnetic resonance (EPR) spectroscopic studies suggest that this chromium-catalyzed reaction probably proceeds through a chromium(I) hydride intermediate.
Collapse
Affiliation(s)
- Yinsong Zhao
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Shaozhong Ge
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| |
Collapse
|
7
|
Zhao Y, Ge S. Chromium‐Catalyzed Selective Dimerization/Hydroboration of Allenes to Access Boryl‐Functionalized Skipped (
E
,
Z
)‐Dienes. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202012344] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Yinsong Zhao
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Singapore
| | - Shaozhong Ge
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Singapore
| |
Collapse
|
8
|
Hasenbeck M, Ahles S, Averdunk A, Becker J, Gellrich U. Die Bildung nukleophiler Allylborane aus molekularem Wasserstoff und Allenen katalysiert durch ein Pyridonatboran, das die Reaktivität eines frustrierten Lewis‐Paares zeigt. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202011790] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Max Hasenbeck
- Institut für Organische Chemie Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Deutschland
| | - Sebastian Ahles
- Institut für Organische Chemie Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Deutschland
| | - Arthur Averdunk
- Institut für Organische Chemie Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Deutschland
| | - Jonathan Becker
- Institut für Anorganische und Analytische Chemie Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Deutschland
| | - Urs Gellrich
- Institut für Organische Chemie Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Deutschland
| |
Collapse
|
9
|
Hasenbeck M, Ahles S, Averdunk A, Becker J, Gellrich U. Formation of Nucleophilic Allylboranes from Molecular Hydrogen and Allenes Catalyzed by a Pyridonate Borane that Displays Frustrated Lewis Pair Reactivity. Angew Chem Int Ed Engl 2020; 59:23885-23891. [PMID: 32926511 PMCID: PMC7814673 DOI: 10.1002/anie.202011790] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Indexed: 11/05/2022]
Abstract
Here we report the in situ generation of nucleophilic allylboranes from H2 and allenes mediated by a pyridonate borane that displays frustrated‐Lewis‐pair reactivity. Experimental and computational mechanistic investigations reveal that upon H2 activation, the covalently bound pyridonate substituent becomes a datively bound pyridone ligand. Dissociation of the formed pyridone borane complex liberates Piers borane and enables a hydroboration of the allene. The allylboranes generated in this way are reactive towards nitriles. A catalytic protocol for the formation of allylboranes from H2 and allenes and the allylation of nitriles has been devised. This catalytic reaction is a conceptually new way to use molecular H2 in organic synthesis.
Collapse
Affiliation(s)
- Max Hasenbeck
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Sebastian Ahles
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Arthur Averdunk
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Jonathan Becker
- Institut für Anorganische und Analytische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Urs Gellrich
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| |
Collapse
|
10
|
Patrick EA, Piers WE. Twenty-five years of bis-pentafluorophenyl borane: a versatile reagent for catalyst and materials synthesis. Chem Commun (Camb) 2020; 56:841-853. [DOI: 10.1039/c9cc08338c] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Highlights of the extensive chemistry and applications of bis-pentafluorophenyl borane (“Piers’ borane”) from the 25 years since its first appearance are featured.
Collapse
|
11
|
Tao X, Škoch K, Daniliuc CG, Kehr G, Erker G. Borane-induced ring closure reaction of oligomethylene-linked bis-allenes. Chem Sci 2019; 11:1542-1548. [PMID: 34084385 PMCID: PMC8148058 DOI: 10.1039/c9sc03870a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The trimethylene-linked bis-allene 3a reacts with Piers' borane [HB(C6F5)2] by a hydroboration/allylboration sequence to generate the cyclization product 5a. Its pyridine adduct was isolated and characterized by X-ray diffraction. Compound 5a undergoes a typical frustrated Lewis pair 1,2-P/B alkene addition reaction with PPh3 to give the heterobicyclic bridged olefinic zwitterionic product 9a. The tetramethylene-linked bis-allene 3b and its phenylene annulated analogue 3c react with HB(C6F5)2 to give the analogous seven-membered ring products 5b,c under mild conditions. The cyclization product 5a undergoes a series of sequential allylboration reactions with two equivalents of allene followed by ring-closure to give the four-component coupling product 12a. It undergoes FLP addition to an exo-methylene group upon treatment with PPh3. Compound 12a is oxidatively converted to the boron-free alcohol.
Collapse
Affiliation(s)
- Xin Tao
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Karel Škoch
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| |
Collapse
|
12
|
Arai S, Izaki A, Amako Y, Nakajima M, Uchiyama M, Nishida A. Regioselective [2+2+2] Cycloaddition Reaction Using Allene‐ynes with Simple Allenes under Nickel Catalysis. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201900719] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Shigeru Arai
- Graduate School of Pharmaceutical SciencesChiba University 1-8-1 Inohana Chuo-ku, Chiba Japan
- Molecular Chirality Research CenterChiba University 1–33 Yayoi-cho, Inage-ku Chiba Japan
| | - Arisa Izaki
- Graduate School of Pharmaceutical SciencesChiba University 1-8-1 Inohana Chuo-ku, Chiba Japan
| | - Yuka Amako
- Graduate School of Pharmaceutical SciencesChiba University 1-8-1 Inohana Chuo-ku, Chiba Japan
| | - Masaya Nakajima
- Graduate School of Pharmaceutical SciencesChiba University 1-8-1 Inohana Chuo-ku, Chiba Japan
- Cluster for Pioneering Research (CPR)Advanced Elements Chemistry Laboratory, RIKEN, 2-1, Hirosawa, Wako Saitama Japan
| | - Masanobu Uchiyama
- Graduate School of Pharmaceutical SciencesThe University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo Japan
- Cluster for Pioneering Research (CPR)Advanced Elements Chemistry Laboratory, RIKEN, 2-1, Hirosawa, Wako Saitama Japan
| | - Atsushi Nishida
- Graduate School of Pharmaceutical SciencesChiba University 1-8-1 Inohana Chuo-ku, Chiba Japan
- Molecular Chirality Research CenterChiba University 1–33 Yayoi-cho, Inage-ku Chiba Japan
| |
Collapse
|
13
|
Tao X, Wölke C, Daniliuc CG, Kehr G, Erker G. Halogenoborane mediated allene cyclooligomerization. Chem Sci 2019; 10:2478-2482. [PMID: 30881677 PMCID: PMC6385850 DOI: 10.1039/c8sc04790a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 12/21/2018] [Indexed: 12/02/2022] Open
Abstract
Allene reacts with the strongly electrophilic halogenoboranes XB(C6F5)2 (X: Cl or Br) by forming a mixture of 1,3,5-trimethylenecyclohexane and the stoichiometric halogeno-borated tetramerization products.
The halogenoboranes XB(C6F5)2 (X: Cl, Br) react with allene to give a mixture of the cyclotrimer 1,3,5-trimethylenecyclohexane (1) and the related halogenoborylated cyclotetramerization products 3a and 3b. Alkyl-substituted allenes were catalytically cyclotrimerized metal-free by XB(C6F5)2 (X: Cl, Br) to give cis,trans-2,4,6-trialkyl-1,3,5-trimethylenecyclohexanes under mild conditions.
Collapse
Affiliation(s)
- Xin Tao
- Organisch-Chemisches Institut , Westfälische Wilhelms-Universität Münster , Corrensstraße 40 , 48149 Münster , Germany .
| | - Christian Wölke
- Organisch-Chemisches Institut , Westfälische Wilhelms-Universität Münster , Corrensstraße 40 , 48149 Münster , Germany .
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut , Westfälische Wilhelms-Universität Münster , Corrensstraße 40 , 48149 Münster , Germany .
| | - Gerald Kehr
- Organisch-Chemisches Institut , Westfälische Wilhelms-Universität Münster , Corrensstraße 40 , 48149 Münster , Germany .
| | - Gerhard Erker
- Organisch-Chemisches Institut , Westfälische Wilhelms-Universität Münster , Corrensstraße 40 , 48149 Münster , Germany .
| |
Collapse
|
14
|
Tao X, Daniliuc CG, Soloviova K, Strassert CA, Kehr G, Erker G. Arylallenes and the halogeno-B(C6F5)2 reagents: facile formation of 2-borylindenes. Chem Commun (Camb) 2019; 55:10166-10169. [DOI: 10.1039/c9cc04199k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Allenylarenes are converted to the respective 2-borylindenes by treatment with chloro- or bromobis(pentafluorophenyl)borane.
Collapse
Affiliation(s)
- Xin Tao
- Organisch-Chemisches Institut
- Westfälische Wilhelms-Universität Münster
- 48149 Münster
- Germany
| | - Constantin G. Daniliuc
- Organisch-Chemisches Institut
- Westfälische Wilhelms-Universität Münster
- 48149 Münster
- Germany
| | - Kateryna Soloviova
- Photophysical Measurements
- Institut für Anorganische und Analytische Chemie – CeNTech
- Westfälische Wilhelms-Universität Münster
- D-48149 Münster
- Germany
| | - Cristian A. Strassert
- Photophysical Measurements
- Institut für Anorganische und Analytische Chemie – CeNTech
- Westfälische Wilhelms-Universität Münster
- D-48149 Münster
- Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut
- Westfälische Wilhelms-Universität Münster
- 48149 Münster
- Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut
- Westfälische Wilhelms-Universität Münster
- 48149 Münster
- Germany
| |
Collapse
|