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Vosberg J, Bouveyron T, Eisen-Winter S, Drönner J, Raabe G, Vanhoorne P, Behnke S, Eisenacher M. Temperature Stable Ion Exchange Resins as Catalysts for the Manufacturing of Vitamin Precursors by Aldol Reaction. Int J Mol Sci 2023; 24:14367. [PMID: 37762670 PMCID: PMC10532307 DOI: 10.3390/ijms241814367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 09/29/2023] Open
Abstract
This study explores the potential of robust, strongly basic type I ion exchange resins-specifically, Amberlyst® A26 OH and Lewatit® K 6465-as catalysts for the aldol condensation of citral and acetone, yielding pseudoionone. Emphasis is placed on their long-term stability and commendable performance in continuous operational settings. The aldol reaction, which traditionally is carried out using aqueous sodium hydroxide as the catalyst, holds the potential for enhanced sustainability and reduced waste production through the use of basic ion exchange resins in heterogeneous catalysis. Density Functional Theory (DFT) calculations are employed to investigate catalyst deactivation mechanisms. The result of these calculations indicates that the active sites of Amberlyst® A26 OH are cleaved more easily than the active sites of Lewatit® K 6465. However, the experimental data show a gradual decline in catalytic activity for both resins. Batch experiments reveal Amberlyst® A26 OH's active sites diminishing, while Lewatit® K 6465 maintains relative consistency. This points to distinct deactivation processes for each catalyst. The constant count of basic sites in Lewatit® K 6465 during the reaction suggests additional factors due to its unique polymer structure. This intriguing observation also highlights an exceptional temperature stability for Lewatit® K 6465 compared to Amberlyst® A26 OH, effectively surmounting one of the prominent challenges associated with the utilization of ion exchange resins in catalytic applications.
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Affiliation(s)
- Jonas Vosberg
- Circular Transformation Lab, TH Köln-University of Applied Sciences, 51379 Leverkusen, Germany
| | - Thomas Bouveyron
- Circular Transformation Lab, TH Köln-University of Applied Sciences, 51379 Leverkusen, Germany
| | - Simon Eisen-Winter
- Circular Transformation Lab, TH Köln-University of Applied Sciences, 51379 Leverkusen, Germany
| | - Jan Drönner
- Circular Transformation Lab, TH Köln-University of Applied Sciences, 51379 Leverkusen, Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Pierre Vanhoorne
- Lanxess Deutschland GmbH, LPT-M-R&I, Kaiser-Wilhelm-Allee, 51369 Leverkusen, Germany
| | - Sven Behnke
- Lanxess Deutschland GmbH, LPT-M-R&I, Kaiser-Wilhelm-Allee, 51369 Leverkusen, Germany
| | - Matthias Eisenacher
- Circular Transformation Lab, TH Köln-University of Applied Sciences, 51379 Leverkusen, Germany
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Kwamen ACN, Schlottmann M, Van Craen D, Isaak E, Baums J, Shen L, Massomi A, Räuber C, Joseph BP, Raabe G, Göb C, Oppel IM, Puttreddy R, Ward JS, Rissanen K, Fröhlich R, Albrecht M. Shedding Light on the Interactions of Hydrocarbon Ester Substituents upon Formation of Dimeric Titanium(IV) Triscatecholates in DMSO Solution. Chemistry 2020; 26:1396-1405. [PMID: 31737953 PMCID: PMC7027801 DOI: 10.1002/chem.201904639] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Indexed: 01/27/2023]
Abstract
The dissociation of hierarchically formed dimeric triple lithium bridged triscatecholate titanium(IV) helicates with hydrocarbyl esters as side groups is systematically investigated in DMSO. Primary alkyl, alkenyl, alkynyl as well as benzyl esters are studied in order to minimize steric effects close to the helicate core. The 1 H NMR dimerization constants for the monomer-dimer equilibrium show some solvent dependent influence of the side chains on the dimer stability. In the dimer, the ability of the hydrocarbyl ester groups to aggregate minimizes their contacts with the solvent molecules. Due to this, most solvophobic alkyl groups show the highest dimerization tendency followed by alkenyls, alkynyls and finally benzyls. Furthermore, trends within the different groups of compounds can be observed. For example, the dimer is destabilized by internal double or triple bonds due to π-π repulsion. A strong indication for solvent supported London dispersion interaction between the ester side groups is found by observation of an even/odd alternation of dimerization constants within the series of n-alkyls, n-Ω-alkenyls or n-Ω-alkynyls. This corresponds to the interaction of the parent hydrocarbons, as documented by an even/odd melting point alternation.
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Affiliation(s)
- A. Carel N. Kwamen
- Institut für Organische ChemieRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - Marcel Schlottmann
- Institut für Organische ChemieRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - David Van Craen
- Institut für Organische ChemieRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - Elisabeth Isaak
- Institut für Organische ChemieRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - Julia Baums
- Institut für Organische ChemieRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - Li Shen
- Institut für Organische ChemieRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - Ali Massomi
- Institut für Organische ChemieRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - Christoph Räuber
- Institut für Organische ChemieRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - Benjamin P. Joseph
- Institut für Organische ChemieRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - Gerhard Raabe
- Institut für Organische ChemieRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - Christian Göb
- Institut für Anorganische ChemieRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - Iris M. Oppel
- Institut für Anorganische ChemieRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - Rakesh Puttreddy
- University of JyväskyläDepartment of ChemistryP.O. Box 35Jyväskylä40014Finland
| | - Jas S. Ward
- University of JyväskyläDepartment of ChemistryP.O. Box 35Jyväskylä40014Finland
| | - Kari Rissanen
- University of JyväskyläDepartment of ChemistryP.O. Box 35Jyväskylä40014Finland
| | - Roland Fröhlich
- Organisch-Chemisches InstitutUniversität MünsterCorrensstrasse 4048149MünsterGermany
| | - Markus Albrecht
- Institut für Organische ChemieRWTH Aachen UniversityLandoltweg 152074AachenGermany
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3
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Erdelmeier I, Bülow G, Woo C, Decker J, Raabe G, Gais H. Cross‐Coupling Reaction of Alkenyl Sulfoximines and Alkenyl Aminosulfoxonium Salts with Organozincs by Dual Nickel Catalysis and Lewis Acid Promotion. Chemistry 2019; 25:8371-8386. [DOI: 10.1002/chem.201901163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Indexed: 11/06/2022]
Affiliation(s)
- Irene Erdelmeier
- Institute of Organic ChemistryRWTH Aachen University Landoltweg 1 52056 Aachen Germany
- Innoverda 38 Rue Dunois 75013 Paris France
| | - Gerd Bülow
- Institute of Organic ChemistryRWTH Aachen University Landoltweg 1 52056 Aachen Germany
| | - Chang‐Wan Woo
- Institute of Organic ChemistryRWTH Aachen University Landoltweg 1 52056 Aachen Germany
| | - Jürgen Decker
- Institute of Organic ChemistryRWTH Aachen University Landoltweg 1 52056 Aachen Germany
| | - Gerhard Raabe
- Institute of Organic ChemistryRWTH Aachen University Landoltweg 1 52056 Aachen Germany
| | - Hans‐Joachim Gais
- Institute of Organic ChemistryRWTH Aachen University Landoltweg 1 52056 Aachen Germany
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4
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Enders D, Zhao L, Raabe G. Asymmetric Synthesis of 2,2-Disubstituted Benzofuranones through an Organocatalytic Alkylation with Nitroallylic Acetates. SYNTHESIS-STUTTGART 2018. [DOI: 10.1055/s-0037-1610337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The asymmetric allylic alkylation of benzofuran-3(2H)-ones with nitroallylic acetates has been achieved employing a bifunctional thiourea organocatalyst via SN2′ substitution. A series of 2,2-disubstituted benzofuranones bearing adjacent tetrasubstituted and tertiary stereocenters have been synthesized with moderate to good yields and very good stereoselectivities.
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Affiliation(s)
- Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen University
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5
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Affiliation(s)
- Zhen Li
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Marcus Frings
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Hao Yu
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Carsten Bolm
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
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6
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Chen X, Gerger TM, Räuber C, Raabe G, Göb C, Oppel IM, Albrecht M. A Helicate‐Based Three‐State Molecular Switch. Angew Chem Int Ed Engl 2018; 57:11817-11820. [DOI: 10.1002/anie.201806607] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Xiaofei Chen
- Institut für Organische ChemieRWTH Aachen University Landoltweg 1 52074 Aachen Germany
| | - Thomas M. Gerger
- Institut für Organische ChemieRWTH Aachen University Landoltweg 1 52074 Aachen Germany
| | - Christoph Räuber
- Institut für Organische ChemieRWTH Aachen University Landoltweg 1 52074 Aachen Germany
| | - Gerhard Raabe
- Institut für Organische ChemieRWTH Aachen University Landoltweg 1 52074 Aachen Germany
| | - Christian Göb
- Institut für Anorganische ChemieRWTH Aachen University Landoltweg 1 52074 Aachen Germany
| | - Iris M. Oppel
- Institut für Anorganische ChemieRWTH Aachen University Landoltweg 1 52074 Aachen Germany
| | - Markus Albrecht
- Institut für Organische ChemieRWTH Aachen University Landoltweg 1 52074 Aachen Germany
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7
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Chen X, Gerger TM, Räuber C, Raabe G, Göb C, Oppel IM, Albrecht M. Ein Helicat-basierter Schalter mit drei adressierbaren Zuständen. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201806607] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Xiaofei Chen
- Institut für Organische Chemie; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Thomas M. Gerger
- Institut für Organische Chemie; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Christoph Räuber
- Institut für Organische Chemie; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Gerhard Raabe
- Institut für Organische Chemie; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Christian Göb
- Institut für Anorganische Chemie; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Iris M. Oppel
- Institut für Anorganische Chemie; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Markus Albrecht
- Institut für Organische Chemie; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
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Wen J, Uto T, Chalupský J, Casher DL, Raabe G, Fleischhauer J, Yanai T, Tsuji H, Komatsu K, Michl J. Magnetic circular dichroism of an unaromatic planar [8]annulene. J PHYS ORG CHEM 2018. [DOI: 10.1002/poc.3854] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jin Wen
- Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic Prague Czech Republic
| | - Takayuki Uto
- Kyoto University Institute for Chemical Research Kyoto Japan
| | - Jakub Chalupský
- Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic Prague Czech Republic
| | - Deborah L. Casher
- Department of Chemistry and Biochemistry University of Colorado Boulder CO U.S.A
| | - Gerhard Raabe
- Institut für Organische Chemie, Rheinisch‐Westfälische Technische Hochschule Aachen Aachen Germany
| | - Joerg Fleischhauer
- Institut für Organische Chemie, Rheinisch‐Westfälische Technische Hochschule Aachen Aachen Germany
| | - Takeshi Yanai
- Department of Theoretical and Computational Molecular Science Institute for Molecular Science Okazaki, Aichi Japan
- JST PRESTO Honcho, Kawaguchi‐shi Saitama Japan
| | - Hayato Tsuji
- Kyoto University Institute for Chemical Research Kyoto Japan
| | - Koichi Komatsu
- Kyoto University Institute for Chemical Research Kyoto Japan
| | - Josef Michl
- Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic Prague Czech Republic
- Department of Chemistry and Biochemistry University of Colorado Boulder CO U.S.A
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9
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Zhao L, Li S, Wang L, Yu S, Raabe G, Enders D. Asymmetric Synthesis of Cyclopentene-Fused Tetrahydroquinolines via N-Heterocyclic Carbene Catalyzed Domino Reactions. SYNTHESIS-STUTTGART 2018. [DOI: 10.1055/s-0036-1591995] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A new strategy for the N-heterocyclic carbene catalyzed asymmetric synthesis of cyclopentene-fused tetrahydroquinoline derivatives has been developed. The one-pot organocatalytic domino protocol allows a direct entry to the characteristic cyclopenta[c]tetrahydroquinoline core of many alkaloids and some potential drugs employing readily available quinolinone and enal substrates in good domino yields and stereoselectivities.
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Affiliation(s)
- Long Zhao
- Institute of Organic Chemistry, RWTH Aachen University
| | - Sun Li
- Institute of Organic Chemistry, RWTH Aachen University
| | - Lei Wang
- Institute of Organic Chemistry, RWTH Aachen University
| | - Shun Yu
- Institute of Organic Chemistry, RWTH Aachen University
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University
| | - Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen University
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10
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Persoon E, Wang Y, Raabe G. Quantum-Chemical Ab Initio Calculations on Inda- and Thallabenzene (C5H5In and C5H5Tl) and their Structural Isomers η5-C5H5In and η5-C5H5Tl. Aust J Chem 2018. [DOI: 10.1071/ch17472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Quantum-chemical ab initio, time-independent, as well as time-dependent density functional theory (TD-DFT) calculations were performed on the so far elusive heterocycles inda- and thallabenzene (C5H5In and C5H5Tl), employing several different methods (MP2, CISD, CCSD, CCSD(T), BD, BD(T), QCISD, QCISD(T), CASSCF, DFT/B3LYP), effective core potentials, and different basis sets. While calculations on the MP2 level predict the ground states of the title compounds to be singlets with the first triplet states between 13 and 15 kcal mol−1 higher in energy, single point calculations with the QCISD(T), CCSD(T), and BD(T) methods at CCSD-optimized structures result in energy differences between the singlet and the triplet states in the range between 0.3 and 2.1 kcal mol−1 in favour of the triplet states. According to a CASSCF(8,8) calculation the triplets are also more stable by about 2.5–2.9 kcal mol−1. Calculations were also performed for the C5v-symmetric η5 structural isomers (cyclopentadienylindium, CpIn, and cyclopentadienylthallium, CpTl, Cp = C5H5) of the title compounds. At the highest level of theory employed in this study, C5H5In is between 79 and 88 kcal mol−1 higher in energy than CpIn, while this energy difference is even larger for thallabenzene where C5H5Tl is energetically between 94 and 102 kcal mol−1 above CpTl. In addition we report on the UV/vis spectra calculated with a TD-DFT method as well as on the spectra of the normal modes of C5H5In and C5H5Tl. Both types of spectra might facilitate identification of the title compounds eventually formed in photolysis or pyrolysis experiments.
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11
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Enders D, Liu Q, Chen XY, Li S, Vetica F, Raabe G. Two-Step Synthesis of α,β-Unsaturated γ-Amino Acid Esters via
N-Heterocyclic Carbene Catalyzed [4+2] Cycloaddition of Enals and Nitroso Compounds. SYNTHESIS-STUTTGART 2018. [DOI: 10.1055/s-0036-1590901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
An efficient strategy for the synthesis of various of α,β-unsaturated γ-amino acid esters has been established employing N-heterocyclic carbene catalyzed [4+2] cycloadditions of β-methyl enals and aromatic nitroso compounds to afford 1,2-oxazin-6-ones in good yields. A subsequent acid-catalyzed esterification under ring opening yields the γ-amino enoates in good yields.
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Enders D, Vetica F, Chauhan P, Mahajan S, Raabe G. Asymmetric Organocatalytic Friedel–Crafts Hydroxyalkylation of Indoles Using Electrophilic Pyrazole-4,5-diones. SYNTHESIS-STUTTGART 2017. [DOI: 10.1055/s-0036-1591860] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The electrophilic reactivity of a series of novel pyrazole-4,5-dione derivatives in the organocatalytic Friedel–Crafts reaction with various substituted indoles has been tested. The disclosed procedure catalyzed by a cinchona alkaloid derivative allows the conjugation of two very important aza-heterocyclic scaffolds to generate a new class of indolylpyrazolones bearing a tetrasubstituted stereocenter in excellent yields (up to 99%) and with enantioselectivities of up to 94:6 er.
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Wen J, Cheng H, Raabe G, Bolm C. Rhodium-Catalyzed [4 + 3] Annulations of Sulfoximines with α,β-Unsaturated Ketones Leading to 1,2-Benzothiazepine 1-Oxides. Org Lett 2017; 19:6020-6023. [DOI: 10.1021/acs.orglett.7b03106] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Jian Wen
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
| | - Hanchao Cheng
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
| | - Carsten Bolm
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
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14
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Giesen AW, Raabe G, Runsink J, Gais HJ. Experimental and Computational Studies of the Structure of Sulfonimidoyl Vinyllithiums. Chemistry 2017; 23:14231-14247. [PMID: 28895210 DOI: 10.1002/chem.201701881] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Indexed: 11/08/2022]
Abstract
tBuCH=C(Li)S(O)(NSO2 Tol)Ph⋅L (L=2THF, TMEDA) (1⋅L) in THF solution is a monomer with a C-Li bond according to NMR spectroscopy and cryoscopy. It was identified as CIP through the scalar 13 C,6 Li coupling and 6 Li,{1 H} NOE experiments. The CIP has a six-membered C-Li-O-S-N-S chelate ring structure. 6 Li,1 H FUCOUP and 6 Li,1 H HMQC NMR experiments of 1⋅TMEDA revealed a scalar 6 Li,1 H coupling across the Li-C=C-H bonds. According to the NMR data the π-bond of 1⋅L is polarized by the negative charge of the anionic C atom. tBuCH=C(Li)S(O)(NMe)Ph (2⋅L) is most likely also a monomer with a C-Li bond. According to 6 Li,{1 H} NOE experiments it has a four-membered C-Li-N-S chelate ring structure. 13 C NMR spectroscopy showed the C-Li bonds of 1⋅L and 2⋅L to be fluxional. 1 H NMR spectroscopy and 1D TOCSY experiments of Ph2 C=C(Li)S(O)(NSO2 Tol)Ph revealed topomerization of the phenyl groups, which is attributed to a fast positional exchange of the Li atom and the sulfonimidoyl group. The fluxionality of the C-Li bond and the interchange of the Li atom and the sulfonimidoyl group at the anionic C atom of sulfonimidoyl vinyllithiums, which result in a low configurational stability, most likely involve the formation of O,Li and N,Li CIPs through heterolysis of the C-Li bond. Ab initio calculation of MeCH=C(Li)S(O)(NMe)Ph yielded an energy minimum structure with a C-Li bond, a four-membered C-Li-N-S chelate ring and a strongly expanded C=C-Li bond angle. According to calculation of MeCH=C(Li)S(O)(NMe)Ph, [MeCH=CS(O)(NMe)Ph]- and MeCH=C(H)S(O)(NMe)Ph deprotonation is not accompanied by a shortening of the C-S bond. Ab initio calculation of MeCH=C(Li)S(O)(NSO2 Me)Ph gave a structure with a C-Li bond and a six-membered C-Li-O-S-N-S chelate ring. 6 Li,1 H NOE experiments and cryoscopy of LiCH2 S(O)(NSO2 Tol)Ph (3) revealed a monomeric CIP with a C-Li bond. The CIP has a six-membered C-Li-O-S-N-S chelate ring structure found in polymeric 3 in the crystal.
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Affiliation(s)
- Alexander Walter Giesen
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.,Merianstrasse 16, 41749, Viersen, Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Jan Runsink
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Hans-Joachim Gais
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
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15
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Vetica F, Bailey S, Chauhan P, Turberg M, Ghaur A, Raabe G, Enders D. Desymmetrization of Cyclopentenediones via
Organocatalytic Cross-Dehydrogenative Coupling. Adv Synth Catal 2017. [DOI: 10.1002/adsc.201700917] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Fabrizio Vetica
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Stephen Bailey
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Pankaj Chauhan
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Mathias Turberg
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Adjmal Ghaur
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Dieter Enders
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
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16
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Bremerich M, Bolm C, Raabe G, Soloshonok VA. Design, Synthesis, and Evaluation of N
-(tert
-Butyl)-Alanine-Derived Chiral Ligands - Aspects of Reactivity and Diastereoselectivity in the Reactions with α-Amino Acids. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Maximilian Bremerich
- Institute for Organic Chemistry; RWTH Aachen University; Landoltweg 1 52056 Aachen Germany
- Department of Organic Chemistry I; Faculty of Chemistry; University of the Basque Country UPV/EHU; Paseo Manuel Lardizábal 3 20018 San Sebastián Spain
| | - Carsten Bolm
- Institute for Organic Chemistry; RWTH Aachen University; Landoltweg 1 52056 Aachen Germany
| | - Gerhard Raabe
- Institute for Organic Chemistry; RWTH Aachen University; Landoltweg 1 52056 Aachen Germany
| | - Vadim A. Soloshonok
- Department of Organic Chemistry I; Faculty of Chemistry; University of the Basque Country UPV/EHU; Paseo Manuel Lardizábal 3 20018 San Sebastián Spain
- IKERBASQUE; Basque Foundation for Science; Maria Diaz de Haro 3 48013 Bilbao Spain
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17
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Zhi Y, Zhao K, Wang A, Englert U, Raabe G, Enders D. Asymmetric Synthesis of Cyclopentane-Substituted Oxindoles via
Organocatalytic Desymmetrization of Cyclopent-4-ene-1,3-diones. Adv Synth Catal 2017. [DOI: 10.1002/adsc.201700358] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Ying Zhi
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Kun Zhao
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Ai Wang
- Institute of Inorganic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Ullrich Englert
- Institute of Inorganic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Dieter Enders
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
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18
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Liu Q, Chen XY, Li S, Jafari E, Raabe G, Enders D. N-Heterocyclic carbene-catalyzed [4+2] annulation of β-methyl enals and cyclic trifluoromethyl ketimines for the asymmetric synthesis of dihydroquinazolinone derivatives. Chem Commun (Camb) 2017; 53:11342-11344. [DOI: 10.1039/c7cc06562k] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The enantioselective oxidative N-heterocyclic carbene-catalyzed [4+2] annulation reaction of β-methyl enals and cyclic trifluoromethyl ketimines has been developed.
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Affiliation(s)
- Qiang Liu
- Institute of Organic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Xiang-Yu Chen
- Institute of Organic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Sun Li
- Institute of Organic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Ehsan Jafari
- Institute of Organic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Dieter Enders
- Institute of Organic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
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19
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Liu Q, Zhao K, Zhi Y, Raabe G, Enders D. Squaramide-catalyzed domino Michael/aza-Henry [3 + 2] cycloaddition: asymmetric synthesis of functionalized 5-trifluoromethyl and 3-nitro substituted pyrrolidines. Org Chem Front 2017. [DOI: 10.1039/c7qo00161d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The diastereo- and enantioselective Michael/aza-Henry [3 + 2] cycloaddition reaction of trifluoromethyl-substituted iminomalonate and nitroalkenes has been developed employing 10 mol% of a quinine-squaramide catalyst.
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Affiliation(s)
- Qiang Liu
- Institute of Organic Chemistry
- RWTH Aachen University
- Aachen
- Germany
| | - Kun Zhao
- Institute of Organic Chemistry
- RWTH Aachen University
- Aachen
- Germany
| | - Ying Zhi
- Institute of Organic Chemistry
- RWTH Aachen University
- Aachen
- Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry
- RWTH Aachen University
- Aachen
- Germany
| | - Dieter Enders
- Institute of Organic Chemistry
- RWTH Aachen University
- Aachen
- Germany
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20
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Enders D, Bröhl N, Kundu D, Raabe G. One-Pot Synthesis of 1-Substituted 1H-Isochromenes by Combining Brønsted Acid with Silver Catalysis. SYNTHESIS-STUTTGART 2016. [DOI: 10.1055/s-0036-1588641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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21
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Wang H, Cheng Y, Becker P, Raabe G, Bolm C. Synthesis of Sulfoximidoyl-Containing Hypervalent Iodine(III) Reagents and Their Use in Transition-Metal-Free Sulfoximidations of Alkynes. Angew Chem Int Ed Engl 2016; 55:12655-8. [DOI: 10.1002/anie.201605743] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Han Wang
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Ying Cheng
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Peter Becker
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Carsten Bolm
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
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22
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Kaya U, Chauhan P, Deckers K, Puttreddy R, Rissanen K, Raabe G, Enders D. Asymmetric Synthesis of Tetrahydrobenzofurans and Annulated Dihydropyrans via Cooperative One-Pot Organo- and Silver-Catalysis. SYNTHESIS-STUTTGART 2016. [DOI: 10.1055/s-0035-1561468] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A low catalyst loading of a squaramide (0.5 mol%) and a silver(I) salt (1 mol%) efficiently catalyzes a one-pot asymmetric Michael addition/hydroalkoxylation reaction between 1,3-diketones and alkyne-tethered nitroalkenes. Depending on the 1,3-dicarbonyl substrate this cooperative catalytic approach opens access to tetrahydrobenzofurans or annulated dihydropyrans in moderate to excellent yields and very good to excellent enantioselectivities.
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Affiliation(s)
- Uğur Kaya
- Institute of Organic Chemistry, RWTH Aachen University
| | | | | | - Rakesh Puttreddy
- Department of Chemistry, Nanoscience Center, University of Jyvaskyla
| | - Kari Rissanen
- Department of Chemistry, Nanoscience Center, University of Jyvaskyla
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University
| | - Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen University
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23
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Albrecht M, Yi H, Köksal O, Raabe G, Pan F, Valkonen A, Rissanen K. CF3: An Electron-Withdrawing Substituent for Aromatic Anion Acceptors? “Side-On” versus “On-Top” Binding of Halides. Chemistry 2016; 22:6956-63. [DOI: 10.1002/chem.201600249] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Markus Albrecht
- Institut für Organische Chemie; RWTH Aachen; Landoltweg 1 52074 Aachen Germany
| | - Hai Yi
- Institut für Organische Chemie; RWTH Aachen; Landoltweg 1 52074 Aachen Germany
| | - Okan Köksal
- Institut für Organische Chemie; RWTH Aachen; Landoltweg 1 52074 Aachen Germany
| | - Gerhard Raabe
- Institut für Organische Chemie; RWTH Aachen; Landoltweg 1 52074 Aachen Germany
| | - Fangfang Pan
- Department of Chemistry; Nanoscience Center; University of Jyväskylä; Survontie 9 B 40014 Jyväskylä Finland
| | - Arto Valkonen
- Department of Chemistry; Nanoscience Center; University of Jyväskylä; Survontie 9 B 40014 Jyväskylä Finland
| | - Kari Rissanen
- Department of Chemistry; Nanoscience Center; University of Jyväskylä; Survontie 9 B 40014 Jyväskylä Finland
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24
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Stodulski M, Kohlhepp SV, Raabe G, Gulder T. Exploration of the Bis(thio)urea-Catalyzed Atropselective Synthesis of Marinopyrrole A. European J Org Chem 2016. [DOI: 10.1002/ejoc.201600147] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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25
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Wang L, Li S, Chauhan P, Hack D, Philipps AR, Puttreddy R, Rissanen K, Raabe G, Enders D. Asymmetric, Three-Component, One-Pot Synthesis of Spiropyrazolones and 2,5-Chromenediones from Aldol Condensation/NHC-Catalyzed Annulation Reactions. Chemistry 2016; 22:5123-7. [DOI: 10.1002/chem.201600515] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Indexed: 01/30/2023]
Affiliation(s)
- Lei Wang
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Sun Li
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Pankaj Chauhan
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Daniel Hack
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Arne R. Philipps
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Rakesh Puttreddy
- Department of Chemistry; Nanoscience Center; University of Jyvaskyla; 40014 JYU Finland
| | - Kari Rissanen
- Department of Chemistry; Nanoscience Center; University of Jyvaskyla; 40014 JYU Finland
| | - Gerhard Raabe
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Dieter Enders
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
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26
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Enders D, Mahajan S, Chauhan P, Blümel M, Puttreddy R, Rissanen K, Raabe G. Asymmetric Synthesis of Spiro Tetrahydrothiophene-indan-1,3-diones via a Squaramide-Catalyzed Sulfa-Michael/Aldol Domino Reaction. SYNTHESIS-STUTTGART 2016. [DOI: 10.1055/s-0035-1560412] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen University
| | | | | | - Marcus Blümel
- Institute of Organic Chemistry, RWTH Aachen University
| | - Rakesh Puttreddy
- Department of Chemistry, Nanoscience Center, University of Jyvaskyla
| | - Kari Rissanen
- Department of Chemistry, Nanoscience Center, University of Jyvaskyla
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University
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27
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Affiliation(s)
- Shunxi Dong
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Marcus Frings
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Hanchao Cheng
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Jian Wen
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Duo Zhang
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Gerhard Raabe
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Carsten Bolm
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
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28
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Van Craen D, Albrecht M, Raabe G, Pan F, Rissanen K. A Supramolecular Chiral Auxiliary Approach: “Remote Control” of Stereochemistry at a Hierarchically Assembled Dimeric Helicate. Chemistry 2016; 22:3255-3258. [DOI: 10.1002/chem.201600158] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Indexed: 12/24/2022]
Affiliation(s)
- David Van Craen
- Institut für Organische Chemie; RWTH Aachen; Landoltweg 1 52074 Aachen Germany
| | - Markus Albrecht
- Institut für Organische Chemie; RWTH Aachen; Landoltweg 1 52074 Aachen Germany
| | - Gerhard Raabe
- Institut für Organische Chemie; RWTH Aachen; Landoltweg 1 52074 Aachen Germany
| | - Fangfang Pan
- Department of Chemistry; University of Jyväskylä, P.O. Box 35; 40014 University Jyväskylä Finland
| | - Kari Rissanen
- Department of Chemistry; University of Jyväskylä, P.O. Box 35; 40014 University Jyväskylä Finland
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29
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Mbarki M, Oettinghaus M, Raabe G. Corrigendum to: Quantum-chemical Ab Initio Calculations on the Donor–Acceptor Complex Pyridine–Borabenzene (C5H5N–BC5H5). Aust J Chem 2016. [DOI: 10.1071/ch13407_co] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The adduct of borabenzene (C5H5B) and pyridine (C5H5N) was studied by means of quantum-chemical ab initio and time-dependent density functional theory calculations at different levels of theory. In the fully optimized structure (MP2/6-311++G**) of the free donor–acceptor complex (C2), the C–B–C angle amounts to 120.6°. The planes of the two aromatic rings enclose a torsion angle of ~40° with a barrier to rotation about the B–N bond of less than 3kcalmol–1 (1kcalmol–1=4.186kJmol–1). The highest computational level applied in this study (complete basis set limit, coupled cluster with single and double excitations (CCSD)) results in an energy associated with the reaction of borabenzene with pyridine of –52.2kcalmol–1. Natural bond orbital analyses were performed to study the bond between the borabenzene and the pyridine unit of the adduct. The UV-vis spectrum of the adduct was calculated employing time-dependent density functional theory methods and the symmetry-adapted cluster-configuration interaction method. Our calculated electronic excitation spectrum of the pyridine adduct as well as its spectrum of the normal modes qualitatively reproduce the characteristic features of the IR and the UV-vis spectra described by experimentalists and thus allows assignment of the observed absorption bands, which in part agree with those by other authors.
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30
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Laubenstein R, Şerb MD, Englert U, Raabe G, Braun T, Braun B. Is it all in the hinge? A kryptoracemate and three of its alternative racemic polymorphs of an aminonitrile. Chem Commun (Camb) 2016; 52:1214-7. [DOI: 10.1039/c5cc08992a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A kryptoracemate, a racemic crystal in a Sohncke space group, and three additional polymorphs, well-ordered racemic structures.
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Affiliation(s)
- R. Laubenstein
- Institute of Chemistry
- Humboldt University Berlin
- 12489 Berlin
- Germany
| | - M.-D. Şerb
- Faculty of Applied Chemistry and Materials Science
- University Politehnica of Bucharest
- Romania
| | - U. Englert
- Institute of Inorganic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - G. Raabe
- Institute of Organic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - T. Braun
- Institute of Chemistry
- Humboldt University Berlin
- 12489 Berlin
- Germany
| | - B. Braun
- Institute of Chemistry
- Humboldt University Berlin
- 12489 Berlin
- Germany
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31
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Hack D, Dürr AB, Deckers K, Chauhan P, Seling N, Rübenach L, Mertens L, Raabe G, Schoenebeck F, Enders D. Asymmetric Synthesis of Spiropyrazolones by Sequential Organo- and Silver Catalysis. Angew Chem Int Ed Engl 2015; 55:1797-800. [PMID: 26676875 PMCID: PMC4725220 DOI: 10.1002/anie.201510602] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Indexed: 11/12/2022]
Abstract
A stereoselective one-pot synthesis of spiropyrazolones through an organocatalytic
asymmetric Michael addition and a formal Conia-ene reaction has been developed.
Depending on the nitroalkene, the 5-exo-dig-cyclization could be achieved by
silver-catalyzed alkyne activation or by oxidation of the intermediate enolate. The
mechanistic pathways have been investigated using computational chemistry and
mechanistic experiments.
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Affiliation(s)
- Daniel Hack
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Alexander B Dürr
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Kristina Deckers
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Pankaj Chauhan
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Nico Seling
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Lukas Rübenach
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Lucas Mertens
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Franziska Schoenebeck
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
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32
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Hack D, Dürr AB, Deckers K, Chauhan P, Seling N, Rübenach L, Mertens L, Raabe G, Schoenebeck F, Enders D. Asymmetric Synthesis of Spiropyrazolones by Sequential Organo- and Silver Catalysis. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201510602] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Daniel Hack
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Alexander B. Dürr
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Kristina Deckers
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Pankaj Chauhan
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Nico Seling
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Lukas Rübenach
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Lucas Mertens
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Franziska Schoenebeck
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Dieter Enders
- Institute of Organic Chemistry; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
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33
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Gerhards F, Griebel N, Runsink J, Raabe G, Gais HJ. Chiral Lithiated Allylic α-Sulfonyl Carbanions: Experimental and Computational Study of Their Structure, Configurational Stability, and Enantioselective Synthesis. Chemistry 2015; 21:17904-20. [PMID: 26494207 DOI: 10.1002/chem.201503123] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Indexed: 11/06/2022]
Abstract
X-ray crystal structure analysis of the lithiated allylic α-sulfonyl carbanions [CH2 CHC(Me)SO2 Ph]Li⋅diglyme, [cC6 H8 SO2 tBu]Li⋅PMDETA and [cC7 H10 SO2 tBu]Li⋅PMDETA showed dimeric and monomeric CIPs, having nearly planar anionic C atoms, only OLi bonds, almost planar allylic units with strong CC bond length alternation and the s-trans conformation around C1C2. They adopt a C1S conformation, which is similar to the one generally found for alkyl and aryl substituted α-sulfonyl carbanions. Cryoscopy of [EtCHCHC(Et)SO2 tBu]Li in THF at 164 K revealed an equilibrium between monomers and dimers in a ratio of 83:17, which is similar to the one found by low temperature NMR spectroscopy. According to NMR spectroscopy the lone-pair orbital at C1 strongly interacts with the CC double bond. Low temperature (6) Li,(1) H NOE experiments of [EtCHCHC(Et)SO2 tBu]Li in THF point to an equilibrium between monomeric CIPs having only OLi bonds and CIPs having both OLi and C1Li bonds. Ab initio calculation of [MeCHCHC(Me)SO2 Me]Li⋅(Me2 O)2 gave three isomeric CIPs having the s-trans conformation and three isomeric CIPs having the s-cis conformation around the C1C2 bond. All s-trans isomers are more stable than the s-cis isomers. At all levels of theory the s-trans isomer having OLi and C1Li bonds is the most stable one followed by the isomer which has two OLi bonds. The allylic unit of the C,O,Li isomer shows strong bond length alternation and the C1 atom is in contrast to the O,Li isomer significantly pyramidalized. According to NBO analysis of the s-trans and s-cis isomers, the interaction of the lone pair at C1 with the π* orbital of the CC double bond is energetically much more favorable than that with the "empty" orbitals at the Li atom. The C1S and C1C2 conformations are determined by the stereoelectronic effects nC -σSR * interaction and allylic conjugation. (1) H DNMR spectroscopy of racemic [EtCHCHC(Et)SO2 tBu]Li, [iPrCHCHC(iPr)SO2 tBu]Li and [EtCHC(Me)C(Et)SO2 tBu]Li in [D8 ]THF gave estimated barriers of enantiomerization of ΔG(≠) =13.2 kcal mol(-1) (270 K), 14.2 kcal mol(-1) (291 K) and 14.2 kcal mol(-1) (295 K), respectively. Deprotonation of sulfone (R)-EtCHCHCH(Et)SO2 tBu (94 % ee) with nBuLi in THF at -105 °C occurred with a calculated enantioselectivity of 93 % ee and gave carbanion (M)-[EtCHCHC(Et)SO2 tBu]Li, the deuteration and alkylation of which with CF3 CO2 D and MeOCH2 I, respectively, proceeded with high enantioselectivities. Time-dependent deuteration of the enantioenriched carbanion (M)-[EtCHCHC(Et)SO2 tBu]Li in THF gave a racemization barrier of ΔG(≠) =12.5 kcal mol(-1) (168 K), which translates to a calculated half-time of racemization of t1/2 =12 min at -105 °C.
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Affiliation(s)
- Frank Gerhards
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen (Germany).,Present address: Philipp Reis Strasse 12, 40215 Düsseldorf (Germany)
| | - Nicole Griebel
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen (Germany).,Present address: Kaiserstrasse 66, 52080 Aachen (Germany)
| | - Jan Runsink
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen (Germany)
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen (Germany)
| | - Hans-Joachim Gais
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen (Germany).
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34
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Enders D, Beceño C, Krappitz T, Raabe G. Asymmetric Synthesis of Tetrahydropyridines via a Brønsted Acid Catalyzed Aza-Diels–Alder Reaction. SYNTHESIS-STUTTGART 2015. [DOI: 10.1055/s-0034-1381058] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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35
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Ni Q, Song X, Xiong J, Raabe G, Enders D. Regio- and stereoselective synthesis of benzothiazolo-pyrimidinones via an NHC-catalyzed Mannich/lactamization domino reaction. Chem Commun (Camb) 2015; 51:1263-6. [PMID: 25476422 PMCID: PMC4612130 DOI: 10.1039/c4cc08594a] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
An NHC-catalyzed regio- and stereoselective Mannich/lactamization domino reaction of N-(benzothiazolyl)imines with α-chloroaldehydes has been developed.
An NHC-catalyzed regio- and stereoselective Mannich/lactamization domino reaction of N-(benzothiazolyl)imines with α-chloroaldehydes has been developed. This new protocol provides a facile approach for the asymmetric synthesis of benzothiazolo-pyrimidinones and a pyrrolo[1,2-a]indolone in moderate to good yields (34–78%) and excellent stereoselectivities (87–99% ee, up to >20 : 1 d.r.).
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Affiliation(s)
- Qijian Ni
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany.
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36
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Abstract
An N-heterocyclic carbene catalyzed enantioselective [3+3] annulation of benzothiazolyl acetates with 2-bromoenals has been developed. The protocol provides a direct asymmetric synthesis of dihydro-1H-benzothiazolopyridinones in good to very good yields and medium ee values. In many cases, the virtually enantiopure heterocycles are available through a single recrystallization (99% ee).
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Affiliation(s)
- Qijian Ni
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Jiawen Xiong
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Xiaoxiao Song
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
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37
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Song X, Ni Q, Zhu C, Raabe G, Enders D. ChemInform Abstract: Asymmetric N-Heterocyclic Carbene Catalyzed Annulation of 2-Alkenylbenzothiazoles with α-Chloro Aldehydes. ACTA ACUST UNITED AC 2015. [DOI: 10.1002/chin.201525198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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38
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Abstract
The efficient asymmetric synthesis of highly substituted succinimides from α,β-unsaturated aldehydes and α-ketoamides via NHC-catalyzed [3+2] cycloaddition has been developed. The new scalable protocol significantly expands the utility of NHC catalysis for the synthesis of heterocycles and provides easy access to assemble a wide range of succinimides from simple starting materials.
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Affiliation(s)
- Lei Wang
- Institute of Organic Chemistry, RWTH Aachen UniversityLandoltweg 1, 52074 Aachen (Germany) E-mail:
| | - Qijian Ni
- Institute of Organic Chemistry, RWTH Aachen UniversityLandoltweg 1, 52074 Aachen (Germany) E-mail:
| | - Marcus Blümel
- Institute of Organic Chemistry, RWTH Aachen UniversityLandoltweg 1, 52074 Aachen (Germany) E-mail:
| | - Tao Shu
- Institute of Organic Chemistry, RWTH Aachen UniversityLandoltweg 1, 52074 Aachen (Germany) E-mail:
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen UniversityLandoltweg 1, 52074 Aachen (Germany) E-mail:
| | - Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen UniversityLandoltweg 1, 52074 Aachen (Germany) E-mail:
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39
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Chauhan P, Mahajan S, Raabe G, Enders D. Organocatalytic one-pot 1,4-/1,6-/1,2-addition sequence for the stereocontrolled formation of six consecutive stereocenters. Chem Commun (Camb) 2015; 51:2270-2. [PMID: 25563802 PMCID: PMC4612129 DOI: 10.1039/c4cc09730k] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
An unprecedented stereoselective organocatalytic one-pot 1,4-/1,6-/1,2-addition sequence between β-dicarbonyl compounds, β-nitroalkenes and 4-nitro-5-styrylisoxazoles sequentially catalyzed by low loading of a squaramide catalyst and an achiral base has been developed. The protocol opens an efficient entry to isoxazole bearing cyclohexanes with six consecutive stereogenic centers including one tetrasubstituted carbon in good yields and excellent diastereo- and enantioselectivities.
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Affiliation(s)
- Pankaj Chauhan
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany.
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40
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Chauhan P, Urbanietz G, Raabe G, Enders D. Asymmetric synthesis of functionalized cyclohexanes bearing five stereocenters via a one-pot organocatalytic Michael-Michael-1,2-addition sequence. Chem Commun (Camb) 2015; 50:6853-5. [PMID: 24842728 PMCID: PMC4268544 DOI: 10.1039/c4cc01885k] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A highly stereoselective one-pot organocatalytic procedure involving a Michael–Michael–1,2-addition sequence provides an efficient access to fully substituted cyclohexanes bearing five contiguous stereocenters in good yields and excellent stereoselectivities.
A highly stereoselective one-pot procedure involving an enantioselective Michael addition promoted by low loading of an amino-squaramide catalyst followed by an achiral base catalyzed domino Michael–Knoevenagel-type 1,2-addition sequence provides efficient access to fully substituted cyclohexanes bearing five contiguous stereogenic centers in good yields (68–86%) and excellent stereoselectivities (>30 : 1 dr and 96–99% ee).
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Affiliation(s)
- Pankaj Chauhan
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany.
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41
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Mahajan S, Chauhan P, Loh CCJ, Uzungelis S, Raabe G, Enders D. Organocatalytic Asymmetric Domino Michael/Henry Reaction of Indolin-3-ones with o-Formyl-β-nitrostyrenes. SYNTHESIS-STUTTGART 2015; 47:1024-1031. [PMID: 26722133 PMCID: PMC4693955 DOI: 10.1055/s-0034-1379943] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A highly diastereo- and enantioselective domino Michael/Henry reaction of 1-acetylindolin-3-ones with o-formyl-(E)-β-nitrostyrenes catalyzed by low loading of a quinine-derived amine-squaramide provides the corresponding indolin-3-one derivatives bearing four adjacent stereogenic centers in good to high yields and with excellent stereoselectivities.
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Affiliation(s)
- Suruchi Mahajan
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Pankaj Chauhan
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Charles C. J. Loh
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Server Uzungelis
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
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42
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Hack D, Chauhan P, Deckers K, Mizutani Y, Raabe G, Enders D. Combining silver- and organocatalysis: an enantioselective sequential catalytic approach towards pyrano-annulated pyrazoles. Chem Commun (Camb) 2015; 51:2266-9. [PMID: 25564304 PMCID: PMC4611987 DOI: 10.1039/c4cc09495f] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 12/23/2014] [Indexed: 01/04/2023]
Abstract
A one-pot asymmetric Michael addition/hydroalkoxylation sequence, catalyzed by a sequential catalytic system consisting of a squaramide and a silver salt, provides a new series of chiral pyrano-annulated pyrazole derivatives in excellent yields (up to 95%) and high enantioselectivities (up to 97% ee).
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Affiliation(s)
- Daniel Hack
- Institute of Organic Chemistry , RWTH Aachen University , Landoltweg 1 , 52074 Aachen , Germany .
| | - Pankaj Chauhan
- Institute of Organic Chemistry , RWTH Aachen University , Landoltweg 1 , 52074 Aachen , Germany .
| | - Kristina Deckers
- Institute of Organic Chemistry , RWTH Aachen University , Landoltweg 1 , 52074 Aachen , Germany .
| | - Yusuke Mizutani
- Nara Institute of Science and Technology (NAIST) , Ikoma , Japan
| | - Gerhard Raabe
- Institute of Organic Chemistry , RWTH Aachen University , Landoltweg 1 , 52074 Aachen , Germany .
| | - Dieter Enders
- Institute of Organic Chemistry , RWTH Aachen University , Landoltweg 1 , 52074 Aachen , Germany .
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43
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Hahn R, Jafari E, Raabe G, Enders D. Organocatalytic Asymmetric Synthesis of Dihydroisoquinolinones via a One-Pot Aza-Henry-Hemiaminalization-Oxidation Sequence. SYNTHESIS-STUTTGART 2015; 47:472-480. [PMID: 26722132 PMCID: PMC4693956 DOI: 10.1055/s-0034-1379398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The asymmetric organocatalytic one-pot synthesis of trans-3,4-disubstituted 3,4-dihydroisoquinolin-1(2H)-ones is described. Starting from 2-(nitromethyl)benzaldehydes and various N-protected aldimines, 5 mol% of a quinine-based squaramide organocatalyst was used to synthesize the title compounds as virtually single diastereomers via an aza-Henry-hemiaminalization-oxidation sequence. Moderate to good yields (39-78%) and moderate to very good enantioselectivities (40-95% ee) were reached.
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Affiliation(s)
- Robert Hahn
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Ehsan Jafari
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
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44
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Zhao K, Shu T, Jia J, Raabe G, Enders D. An organocatalytic Mannich/denitration reaction for the asymmetric synthesis of 3-ethylacetate-substitued 3-amino-2-oxindoles: formal synthesis of AG-041R. Chemistry 2015; 21:3933-6. [PMID: 25630891 DOI: 10.1002/chem.201406422] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Indexed: 11/06/2022]
Abstract
The highly enantioselective organocatalytic addition of ethyl nitroacetate to isatin-derived N-Boc ketimines (Boc = tert-butoxycarbonyl), followed by the removal of the nitro group, is described. The scalable reaction sequence leads to the title compounds as important intermediates of pyrroloindoline alkaloids and related drugs in excellent yields and enantioselectivities. The synthesis of the hexahydrofurano[2,3-b]indole skeleton, the spirocarbamate oxindole unit, and the formal synthesis of AG-041R have been carried out to demonstrate the synthetic utility of this protocol.
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Affiliation(s)
- Kun Zhao
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen (Germany), Fax: (+49) 241-809-2127 http://www.oc.rwth-aachen.de/akenders/AKEN_D.HTM
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45
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Zou LH, Philipps AR, Raabe G, Enders D. Asymmetric synthesis of fully substituted cyclopentane-oxindoles through an organocatalytic triple Michael domino reaction. Chemistry 2015; 21:1004-8. [PMID: 25470781 PMCID: PMC4648040 DOI: 10.1002/chem.201406047] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Indexed: 12/19/2022]
Abstract
An efficient, highly stereoselective asymmetric synthesis of fully functionalized cyclopentanes bearing an oxindole moiety and several other functional groups in one pot has been developed. Key step is an organocatalytic triple Michael domino reaction forming three C-C bonds and six stereocenters, including a quaternary one. Starting from equimolar amounts of simple substrates, a high molecular complexity can be reached after a Wittig olefination in one pot. The new protocol can easily be scaled up to gram amounts.
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Affiliation(s)
- Liang-Hua Zou
- Institute of Organic Chemistry, RWTH Aachen UniversityLandoltweg 1, 52074 Aachen (Germany) E-mail:
| | - Arne R Philipps
- Institute of Organic Chemistry, RWTH Aachen UniversityLandoltweg 1, 52074 Aachen (Germany) E-mail:
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen UniversityLandoltweg 1, 52074 Aachen (Germany) E-mail:
| | - Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen UniversityLandoltweg 1, 52074 Aachen (Germany) E-mail:
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46
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Ni Q, Xiong J, Song X, Raabe G, Enders D. NHC-catalyzed activation of α,β-unsaturated N-acyltriazoles: an easy access to dihydropyranones. Chem Commun (Camb) 2015; 51:14628-31. [DOI: 10.1039/c5cc06044c] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Employing the NHC-catalyzed activation of α,β-unsaturated N-acyltriazoles an efficient enantioselective synthesis of dihydropyranones via a formal [3+3] cycloaddition with 1,3-dicarbonyl compounds is described.
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Affiliation(s)
- Qijian Ni
- Institute of Organic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Jiawen Xiong
- Institute of Organic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Xiaoxiao Song
- Institute of Organic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Dieter Enders
- Institute of Organic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
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47
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Sun ZH, Albrecht M, Raabe G, Pan FF, Räuber C. Solvent-Dependent Enthalpic versus Entropic Anion Binding by Biaryl Substituted Quinoline Based Anion Receptors. J Phys Chem B 2014; 119:301-6. [DOI: 10.1021/jp510796f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Zhan-Hu Sun
- Institut
für Organische Chemie, RWTH Aachen, Landoltweg 1, D-52074 Aachen, Germany
| | - Markus Albrecht
- Institut
für Organische Chemie, RWTH Aachen, Landoltweg 1, D-52074 Aachen, Germany
| | - Gerhard Raabe
- Institut
für Organische Chemie, RWTH Aachen, Landoltweg 1, D-52074 Aachen, Germany
| | - Fang-Fang Pan
- Institut
für Anorganische Chemie, RWTH Aachen, Landoltweg 1, D-52074 Aachen, Germany
| | - Christoph Räuber
- Institut
für Organische Chemie, RWTH Aachen, Landoltweg 1, D-52074 Aachen, Germany
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48
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Blümel M, Chauhan P, Hahn R, Raabe G, Enders D. Asymmetric synthesis of tetrahydropyridines via an organocatalytic one-pot multicomponent Michael/aza-Henry/cyclization triple domino reaction. Org Lett 2014; 16:6012-5. [PMID: 25379786 PMCID: PMC4611353 DOI: 10.1021/ol503024d] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Indexed: 12/22/2022]
Abstract
A low loading of a quinine-derived squaramide efficiently catalyzes the triple-domino Michael/aza-Henry/cyclization reaction between 1,3-dicarbonyl compounds, β-nitroolefins, and aldimines to provide tetrahydropyridines bearing three contiguous stereogenic centers in good yields, excellent enantiomeric excesses, and up to high diastereomeric ratios.
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Affiliation(s)
- Marcus Blümel
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Pankaj Chauhan
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Robert Hahn
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
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49
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Abstract
Diastereo- and enantioselective N-heterocyclic carbene catalyzed 1-azadiene Diels-Alder reactions of (E)-2-styrylbenzothiazoles with α-chloro aldehydes are reported. This annulation strategy provides an efficient access to medicinally important dihydrobenzothiazolopyridin-1-ones in good to excellent yields (44-97%) with very good to excellent stereoselectivities (up to 9:1 dr, 98% ee) and tolerates quite a range of substituents.
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Affiliation(s)
- Xiaoxiao Song
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Qijian Ni
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Chen Zhu
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Gerhard Raabe
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
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50
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Heß T, Raabe G, Gais HJ. Lithium-Titanium Exchange of Tertiary α-Sulfonyl Carbanions: Synthesis, Structure, Dynamics and Reactivity of Bis(1-sulfonylalkyl)titaniums. European J Org Chem 2014. [DOI: 10.1002/ejoc.201402896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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