1
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de Robichon M, Kratz T, Beyer F, Zuber J, Merten C, Bach T. Enantioselective, Intermolecular [ π2+ σ2] Photocycloaddition Reactions of 2(1 H)-Quinolones and Bicyclo[1.1.0]butanes. J Am Chem Soc 2023. [PMID: 37917070 DOI: 10.1021/jacs.3c08404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
1-Substituted bicyclo[1.1.0]butanes add enantioselectively to 2(1H)-quinolones upon irradiation (λ = 366 nm) in the presence of a chiral complexing agent. A two-point hydrogen bond between the quinolone and the template is responsible for stereocontrol in the photocycloaddition reaction. The reaction leads to the formation of products with a chiral bicyclo[2.1.1]hexane skeleton in high enantiomeric excess (91-99% ee). The chiral template can be almost quantitatively (97%) recovered and used in another reaction. A triplet reaction pathway is likely, and sensitization is a suitable tool if the reaction is to be performed with visible light (λ = 420 nm).
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Affiliation(s)
- Morgane de Robichon
- School of Natural Sciences, Department Chemie, and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Thilo Kratz
- School of Natural Sciences, Department Chemie, and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Frederike Beyer
- Organische Chemie II, Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Julian Zuber
- School of Natural Sciences, Department Chemie, and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Christian Merten
- Organische Chemie II, Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Thorsten Bach
- School of Natural Sciences, Department Chemie, and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany
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2
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Trimble JS, Crawshaw R, Hardy FJ, Levy CW, Brown MJB, Fuerst DE, Heyes DJ, Obexer R, Green AP. A designed photoenzyme for enantioselective [2+2] cycloadditions. Nature 2022; 611:709-714. [PMID: 36130727 DOI: 10.1038/s41586-022-05335-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 09/12/2022] [Indexed: 11/09/2022]
Abstract
The ability to program new modes of catalysis into proteins would allow the development of enzyme families with functions beyond those found in nature. To this end, genetic code expansion methodology holds particular promise, as it allows the site-selective introduction of new functional elements into proteins as noncanonical amino acid side chains1-4. Here we exploit an expanded genetic code to develop a photoenzyme that operates by means of triplet energy transfer (EnT) catalysis, a versatile mode of reactivity in organic synthesis that is not accessible to biocatalysis at present5-12. Installation of a genetically encoded photosensitizer into the beta-propeller scaffold of DA_20_00 (ref. 13) converts a de novo Diels-Alderase into a photoenzyme for [2+2] cycloadditions (EnT1.0). Subsequent development and implementation of a platform for photoenzyme evolution afforded an efficient and enantioselective enzyme (EnT1.3, up to 99% enantiomeric excess (e.e.)) that can promote intramolecular and bimolecular cycloadditions, including transformations that have proved challenging to achieve selectively with small-molecule catalysts. EnT1.3 performs >300 turnovers and, in contrast to small-molecule photocatalysts, can operate effectively under aerobic conditions and at ambient temperatures. An X-ray crystal structure of an EnT1.3-product complex shows how multiple functional components work in synergy to promote efficient and selective photocatalysis. This study opens up a wealth of new excited-state chemistry in protein active sites and establishes the framework for developing a new generation of enantioselective photocatalysts.
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Affiliation(s)
- Jonathan S Trimble
- Department of Chemistry, The University of Manchester, Manchester, UK
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, UK
| | - Rebecca Crawshaw
- Department of Chemistry, The University of Manchester, Manchester, UK
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, UK
| | - Florence J Hardy
- Department of Chemistry, The University of Manchester, Manchester, UK
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, UK
| | - Colin W Levy
- Department of Chemistry, The University of Manchester, Manchester, UK
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, UK
| | - Murray J B Brown
- Synthetic Biochemistry, Medicine Development and Supply, GlaxoSmithKline Medicines Research Centre, Stevenage, UK
| | - Douglas E Fuerst
- Synthetic Biochemistry, Medicine Development and Supply, GlaxoSmithKline, Collegeville, PA, USA
| | - Derren J Heyes
- Department of Chemistry, The University of Manchester, Manchester, UK
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, UK
| | - Richard Obexer
- Department of Chemistry, The University of Manchester, Manchester, UK
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, UK
| | - Anthony P Green
- Department of Chemistry, The University of Manchester, Manchester, UK.
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, UK.
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3
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Reek JNH, de Bruin B, Pullen S, Mooibroek TJ, Kluwer AM, Caumes X. Transition Metal Catalysis Controlled by Hydrogen Bonding in the Second Coordination Sphere. Chem Rev 2022; 122:12308-12369. [PMID: 35593647 PMCID: PMC9335700 DOI: 10.1021/acs.chemrev.1c00862] [Citation(s) in RCA: 54] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Transition metal catalysis is of utmost importance for the development of sustainable processes in academia and industry. The activity and selectivity of metal complexes are typically the result of the interplay between ligand and metal properties. As the ligand can be chemically altered, a large research focus has been on ligand development. More recently, it has been recognized that further control over activity and selectivity can be achieved by using the "second coordination sphere", which can be seen as the region beyond the direct coordination sphere of the metal center. Hydrogen bonds appear to be very useful interactions in this context as they typically have sufficient strength and directionality to exert control of the second coordination sphere, yet hydrogen bonds are typically very dynamic, allowing fast turnover. In this review we have highlighted several key features of hydrogen bonding interactions and have summarized the use of hydrogen bonding to program the second coordination sphere. Such control can be achieved by bridging two ligands that are coordinated to a metal center to effectively lead to supramolecular bidentate ligands. In addition, hydrogen bonding can be used to preorganize a substrate that is coordinated to the metal center. Both strategies lead to catalysts with superior properties in a variety of metal catalyzed transformations, including (asymmetric) hydrogenation, hydroformylation, C-H activation, oxidation, radical-type transformations, and photochemical reactions.
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Affiliation(s)
- Joost N H Reek
- Homogeneous and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.,InCatT B.V., Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Sonja Pullen
- Homogeneous and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Tiddo J Mooibroek
- Homogeneous and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | | | - Xavier Caumes
- InCatT B.V., Science Park 904, 1098 XH Amsterdam, The Netherlands
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4
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Takagi R, Tanimoto T. Enantioselective [2 + 2] photocycloaddition of quinolone using a C1-symmetric chiral phosphoric acid as a visible-light photocatalyst. Org Biomol Chem 2022; 20:3940-3947. [PMID: 35506886 DOI: 10.1039/d2ob00607c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The enantioselective intra- and intermolecular [2 + 2] photocycloaddition of quinolone using a C1-symmetric chiral phosphoric acid as a visible-light photocatalyst is developed. The thioxanthone chromophore on phosphoric acid plays an important role in both phototransformation and enantioselectivity.
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Affiliation(s)
- Ryukichi Takagi
- Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan.
| | - Takaaki Tanimoto
- Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan.
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5
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Guo F, Wang H, Ye X, Tan CH. Advanced Synthesis Using Photocatalysis Involved Dual Catalytic System. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Fenfen Guo
- Zhejiang University of Technology College of Pharmaceutical Science CHINA
| | - Hong Wang
- Zhejiang University of Technology College of Pharmaceutical Science CHINA
| | - Xinyi Ye
- Zhejiang University of Technology College of Pharmaceutical Science 18 Chaowang Road 310014 Hangzhou CHINA
| | - Choon-Hong Tan
- Nanyang Technological University School of Physical and Mathematical Sciences SINGAPORE
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6
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Genzink MJ, Kidd JB, Swords WB, Yoon TP. Chiral Photocatalyst Structures in Asymmetric Photochemical Synthesis. Chem Rev 2022; 122:1654-1716. [PMID: 34606251 PMCID: PMC8792375 DOI: 10.1021/acs.chemrev.1c00467] [Citation(s) in RCA: 138] [Impact Index Per Article: 69.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Asymmetric catalysis is a major theme of research in contemporary synthetic organic chemistry. The discovery of general strategies for highly enantioselective photochemical reactions, however, has been a relatively recent development, and the variety of photoreactions that can be conducted in a stereocontrolled manner is consequently somewhat limited. Asymmetric photocatalysis is complicated by the short lifetimes and high reactivities characteristic of photogenerated reactive intermediates; the design of catalyst architectures that can provide effective enantiodifferentiating environments for these intermediates while minimizing the participation of uncontrolled racemic background processes has proven to be a key challenge for progress in this field. This review provides a summary of the chiral catalyst structures that have been studied for solution-phase asymmetric photochemistry, including chiral organic sensitizers, inorganic chromophores, and soluble macromolecules. While some of these photocatalysts are derived from privileged catalyst structures that are effective for both ground-state and photochemical transformations, others are structural designs unique to photocatalysis and offer insight into the logic required for highly effective stereocontrolled photocatalysis.
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Affiliation(s)
- Matthew J Genzink
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Jesse B Kidd
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Wesley B Swords
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Tehshik P Yoon
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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7
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Mondal S, Dumur F, Gigmes D, Sibi MP, Bertrand MP, Nechab M. Enantioselective Radical Reactions Using Chiral Catalysts. Chem Rev 2022; 122:5842-5976. [DOI: 10.1021/acs.chemrev.1c00582] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Shovan Mondal
- Department of Chemistry, Syamsundar College, Shyamsundar 713424, West Bengal, India
| | - Frédéric Dumur
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, F-13390e Marseille, France
| | - Didier Gigmes
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, F-13390e Marseille, France
| | - Mukund P. Sibi
- Department of Chemistry and Biochemistry North Dakota State University, Fargo, North Dakota 58108, United States
| | - Michèle P. Bertrand
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, F-13390e Marseille, France
| | - Malek Nechab
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, F-13390e Marseille, France
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8
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Schmid L, Glaser F, Schaer R, Wenger OS. High Triplet Energy Iridium(III) Isocyanoborato Complex for Photochemical Upconversion, Photoredox and Energy Transfer Catalysis. J Am Chem Soc 2022; 144:963-976. [PMID: 34985882 DOI: 10.1021/jacs.1c11667] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cyclometalated Ir(III) complexes are often chosen as catalysts for challenging photoredox and triplet-triplet-energy-transfer (TTET) catalyzed reactions, and they are of interest for upconversion into the ultraviolet spectral range. However, the triplet energies of commonly employed Ir(III) photosensitizers are typically limited to values around 2.5-2.75 eV. Here, we report on a new Ir(III) luminophore, with an unusually high triplet energy near 3.0 eV owing to the modification of a previously reported Ir(III) complex with isocyanoborato ligands. Compared to a nonborylated cyanido precursor complex, the introduction of B(C6F5)3 units in the second coordination sphere results in substantially improved photophysical properties, in particular a high luminescence quantum yield (0.87) and a long excited-state lifetime (13.0 μs), in addition to the high triplet energy. These favorable properties (including good long-term photostability) facilitate exceptionally challenging organic triplet photoreactions and (sensitized) triplet-triplet annihilation upconversion to a fluorescent singlet excited state beyond 4 eV, unusually deep in the ultraviolet region. The new Ir(III) complex photocatalyzes a sigmatropic shift and [2 + 2] cycloaddition reactions that are unattainable with common transition metal-based photosensitizers. In the presence of a sacrificial electron donor, it furthermore is applicable to demanding photoreductions, including dehalogenations, detosylations, and the degradation of a lignin model substrate. Our study demonstrates how rational ligand design of transition-metal complexes (including underexplored second coordination sphere effects) can be used to enhance their photophysical properties and thereby broaden their application potential in solar energy conversion and synthetic photochemistry.
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Affiliation(s)
- Lucius Schmid
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Felix Glaser
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Raoul Schaer
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
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9
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Jayasekara GK, Antolini C, Smith MA, Jacoby DJ, Escolastico J, Girard N, Young BT, Hayes D. Mechanisms of the Cu(I)-Catalyzed Intermolecular Photocycloaddition Reaction Revealed by Optical and X-ray Transient Absorption Spectroscopies. J Am Chem Soc 2021; 143:19356-19364. [PMID: 34752703 DOI: 10.1021/jacs.1c07282] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The [2 + 2] photocycloaddition provides a simple, single-step route to cyclobutane moieties that would otherwise be disfavored or impossible due to ring strain and/or steric interactions. We have used a combination of optical and X-ray transient absorption spectroscopies to elucidate the mechanism of the Cu(I)-catalyzed intermolecular photocycloaddition reaction using norbornene and cyclohexene as model substrates. We find that for norbornene the reaction proceeds through an initial metal-to-ligand charge transfer (MLCT) state that persists for 18 ns before the metal returns to the monovalent oxidation state. The Cu K-edge spectrum continues to evolve until ∼5 μs and then remains unchanged for the 50 μs duration of the measurement, reflecting product formation and ligand dissociation. We hypothesize that the MLCT transition and reverse electron transfer serve to sensitize the triplet excited state of one of the norbornene ligands, which then dimerizes with the other to give the product. For the case of cyclohexene, however, we do not observe a charge transfer state following photoexcitation and instead find evidence for an increase in the metal-ligand bond strength that persists for several ns before product formation occurs. This is consistent with a mechanism in which ligand photoisomerization is the initial step, which was first proposed by Salomon and Kochi in 1974 to explain the stereoselectivity of the reaction. Our investigation reveals how this photocatalytic reaction may be directed along strikingly disparate trajectories by only very minor changes to the structure of the substrate.
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Affiliation(s)
- Gethmini K Jayasekara
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Cali Antolini
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Melissa A Smith
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Danielle J Jacoby
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Jacqueline Escolastico
- Department of Physical Sciences, Rhode Island College, 600 Mt Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Nathan Girard
- Department of Physical Sciences, Rhode Island College, 600 Mt Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Benjamin T Young
- Department of Physical Sciences, Rhode Island College, 600 Mt Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Dugan Hayes
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
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10
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Großkopf J, Kratz T, Rigotti T, Bach T. Enantioselective Photochemical Reactions Enabled by Triplet Energy Transfer. Chem Rev 2021; 122:1626-1653. [PMID: 34227803 DOI: 10.1021/acs.chemrev.1c00272] [Citation(s) in RCA: 168] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
For molecules with a singlet ground state, the population of triplet states is mainly possible (a) by direct excitation and subsequent intersystem crossing or (b) by energy transfer from an appropriate sensitizer. The latter scenario enables a catalytic photochemical reaction in which the sensitizer adopts the role of a catalyst undergoing several cycles of photon absorption and subsequent energy transfer to the substrate. If the product molecule of a triplet-sensitized process is chiral, this process can proceed enantioselectively upon judicious choice of a chiral triplet sensitizer. An enantioselective reaction can also occur in a dual catalytic approach in which, apart from an achiral sensitizer, a second chiral catalyst activates the substrate toward sensitization. Although the idea of enantioselective photochemical reactions via triplet intermediates has been pursued for more than 50 years, notable selectivities exceeding 90% enantiomeric excess (ee) have only been realized in the past decade. This review attempts to provide a comprehensive survey on the various photochemical reactions which were rendered enantioselective by triplet sensitization.
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Affiliation(s)
- Johannes Großkopf
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, D-85747 Garching, Germany
| | - Thilo Kratz
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, D-85747 Garching, Germany
| | - Thomas Rigotti
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, D-85747 Garching, Germany
| | - Thorsten Bach
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, D-85747 Garching, Germany
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11
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Hong BC. Enantioselective synthesis enabled by visible light photocatalysis. Org Biomol Chem 2020; 18:4298-4353. [PMID: 32458948 DOI: 10.1039/d0ob00759e] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Enantioselective photoreaction has been a synthetic challenge for decades. With the continuous development of modern visible light photocatalysis and asymmetric catalysis, remarkable advances have been achieved through the synergistic action of these catalytic reactions, allowing the construction of various enantiomerically enriched molecules that were once inaccessible using photocatalytic reactions. This review presents some of the contemporary developments in enantioselective visible-light photocatalysis reactions, covering the period from 2008 to March 2020, with the contents classified by catalysis type.
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Affiliation(s)
- Bor-Cherng Hong
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chia-Yi, 621, Taiwan, Republic of China.
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12
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Li X, Jandl C, Bach T. Visible-Light-Mediated Enantioselective Photoreactions of 3-Alkylquinolones with 4-O-Tethered Alkenes and Allenes. Org Lett 2020; 22:3618-3622. [DOI: 10.1021/acs.orglett.0c01065] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xinyao Li
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, 85747 Garching, Germany
| | - Christian Jandl
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, 85747 Garching, Germany
| | - Thorsten Bach
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, 85747 Garching, Germany
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13
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Takagi R, Tabuchi C. Enantioselective intramolecular [2 + 2] photocycloaddition using phosphoric acid as a chiral template. Org Biomol Chem 2020; 18:9261-9267. [PMID: 33150919 DOI: 10.1039/d0ob02054k] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The enantioselective intramolecular [2 + 2] photocycloaddition of 4-bishomoally-2-quinolone (quinolinone) using phosphoric acid as a chiral template has been developed. Mechanistic studies using several NMR measurement techniques and density functional theory (DFT) calculations indicate that π-π interactions between the phenyl ring on phosphoric acid and quinolinone play important roles in the enantioselectivity.
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Affiliation(s)
- Ryukichi Takagi
- Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan.
| | - Chihiro Tabuchi
- Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan.
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Burg F, Bach T. Lactam Hydrogen Bonds as Control Elements in Enantioselective Transition-Metal-Catalyzed and Photochemical Reactions. J Org Chem 2019; 84:8815-8836. [DOI: 10.1021/acs.joc.9b01299] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Finn Burg
- Department of Chemistry and Catalysis Research Center (CRC), Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Thorsten Bach
- Department of Chemistry and Catalysis Research Center (CRC), Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany
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15
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Abstract
Abstract
This review summarizes results in the field of hydrogen-bond templated enantioselective photochemistry. It covers both the stoichemiometric use of templates derived from Kemp’s triacid as well as photocatalytic methods to achieve high enantioselectivities in photochemical processes.
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16
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Dantas JA, Correia JTM, Paixão MW, Corrêa AG. Photochemistry of Carbonyl Compounds: Application in Metal‐Free Reactions. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900044] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Juliana A. Dantas
- Centre of Excellence for Research in Sustainable Chemistry Department of ChemistryFederal University of São Carlos 13565-905 São Carlos, SP Brazil
| | - José Tiago M. Correia
- Centre of Excellence for Research in Sustainable Chemistry Department of ChemistryFederal University of São Carlos 13565-905 São Carlos, SP Brazil
| | - Marcio W. Paixão
- Centre of Excellence for Research in Sustainable Chemistry Department of ChemistryFederal University of São Carlos 13565-905 São Carlos, SP Brazil
| | - Arlene G. Corrêa
- Centre of Excellence for Research in Sustainable Chemistry Department of ChemistryFederal University of São Carlos 13565-905 São Carlos, SP Brazil
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17
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Modha SG, Pöthig A, Dreuw A, Bach T. [6π] Photocyclization to cis-Hexahydrocarbazol-4-ones: Substrate Modification, Mechanism, and Scope. J Org Chem 2019; 84:1139-1153. [PMID: 30648858 PMCID: PMC6362434 DOI: 10.1021/acs.joc.8b03144] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
![]()
Upon irradiation at λ = 366
nm, tertiary N-alkoxycarbonyl-N-aryl-β-enaminones
furnished
exclusively the trans-hexahydrocarbazol-4-ones by
a conrotatory [6π] photocyclization but epimerized on silica
to cis-hexahydrocarbazol-4-ones (14 examples, 44–98%
yield). The acceptor substitution on the nitrogen atom enhanced the
stability of the cyclized products compared to N-alkyl-N-aryl-β-enaminones reported previously. The mechanism
of the [6π] photocyclization was investigated by quenching experiments,
deuterium-labeling experiments, and DFT calculations, suggesting a
triplet pathway for the conrotatory ring closure followed by a suprafacial
[1,4] hydrogen migration.
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Affiliation(s)
- Sachin G Modha
- Department of Chemistry and Catalysis Research Center (CRC) , Technical University of Munich , Lichtenbergstrasse 4 , 85747 Garching , Germany
| | - Alexander Pöthig
- Department of Chemistry and Catalysis Research Center (CRC) , Technical University of Munich , Lichtenbergstrasse 4 , 85747 Garching , Germany
| | - Andreas Dreuw
- Interdisciplinary Center for Scientific Computing , Ruprecht-Karls University , Im Neuenheimer Feld 205A , 69120 Heidelberg , Germany
| | - Thorsten Bach
- Department of Chemistry and Catalysis Research Center (CRC) , Technical University of Munich , Lichtenbergstrasse 4 , 85747 Garching , Germany
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18
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Brenninger C, Jolliffe JD, Bach T. Chromophore Activation of α,β-Unsaturated Carbonyl Compounds and Its Application to Enantioselective Photochemical Reactions. Angew Chem Int Ed Engl 2018; 57:14338-14349. [PMID: 29806882 PMCID: PMC6220886 DOI: 10.1002/anie.201804006] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Indexed: 11/28/2022]
Abstract
The first law of photochemistry, as described by Theodor von Grotthuß and John W. Draper, states that only the light absorbed by the irradiated matter can effect photochemical change. Consequently, the photochemical behavior of a molecule can be controlled by bringing its absorbance properties in line with the emission of the light source. A compound with a chromophore that only absorbs light at short wavelengths will not be excited by light of longer wavelengths. If one can reversibly modify the photophysical properties of a compound with a chemical activator, then it is possible to photoexcite only the activated species. For α,β-unsaturated carbonyl compounds, the use of Lewis acids, Brønsted acids, or the formation of the respective iminium ions can bring about the desired chromophore activation to catalyze a photochemical reaction at a given wavelength. In this Minireview, the concept of chromophore activation will be illustrated, and examples of its implementation in enantioselective catalysis will be discussed.
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Affiliation(s)
- Christoph Brenninger
- Lehrstuhl für Organische Chemie I and Catalysis Research Center (CRC)Technische Universität MünchenLichtenbergstr. 485747GarchingGermany
| | - John D. Jolliffe
- Lehrstuhl für Organische Chemie I and Catalysis Research Center (CRC)Technische Universität MünchenLichtenbergstr. 485747GarchingGermany
| | - Thorsten Bach
- Lehrstuhl für Organische Chemie I and Catalysis Research Center (CRC)Technische Universität MünchenLichtenbergstr. 485747GarchingGermany
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19
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Brenninger C, Jolliffe JD, Bach T. Chromophoraktivierung von α,β-ungesättigten Carbonylverbindungen und ihre Anwendung in enantioselektiven Photoreaktionen. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Christoph Brenninger
- Lehrstuhl für Organische Chemie I und Catalysis Research Center (CRC); Technische Universität München; Lichtenbergstraße 4 85747 Garching Deutschland
| | - John D. Jolliffe
- Lehrstuhl für Organische Chemie I und Catalysis Research Center (CRC); Technische Universität München; Lichtenbergstraße 4 85747 Garching Deutschland
| | - Thorsten Bach
- Lehrstuhl für Organische Chemie I und Catalysis Research Center (CRC); Technische Universität München; Lichtenbergstraße 4 85747 Garching Deutschland
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20
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Molloy JJ, Metternich JB, Daniliuc CG, Watson AJB, Gilmour R. Contra-Thermodynamic, Photocatalytic E
→Z
Isomerization of Styrenyl Boron Species: Vectors to Facilitate Exploration of Two-Dimensional Chemical Space. Angew Chem Int Ed Engl 2018; 57:3168-3172. [DOI: 10.1002/anie.201800286] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Indexed: 01/13/2023]
Affiliation(s)
- John J. Molloy
- WESTCHEM; Department of Pure and Applied Chemistry; University of Strathclyde; 295 Cathedral Street Glasgow UK
| | - Jan B. Metternich
- Organisch Chemisches Institut; Westfälische Wilhelms-Universität Münster; Corrensstraße 40 48149 Münster Germany
- Current address: Department of Chemistry and Chemical Biology; Harvard University; 12 Oxford Street Cambridge MA 02138 USA
| | - Constantin G. Daniliuc
- Organisch Chemisches Institut; Westfälische Wilhelms-Universität Münster; Corrensstraße 40 48149 Münster Germany
| | - Allan J. B. Watson
- EASTCHEM School of Chemistry; University of St Andrews, North Haugh; St Andrews, Fife UK
| | - Ryan Gilmour
- Organisch Chemisches Institut; Westfälische Wilhelms-Universität Münster; Corrensstraße 40 48149 Münster Germany
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21
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Molloy JJ, Metternich JB, Daniliuc CG, Watson AJB, Gilmour R. Contra-Thermodynamic, Photocatalytic E
→Z
Isomerization of Styrenyl Boron Species: Vectors to Facilitate Exploration of Two-Dimensional Chemical Space. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201800286] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- John J. Molloy
- WESTCHEM; Department of Pure and Applied Chemistry; University of Strathclyde; 295 Cathedral Street Glasgow UK
| | - Jan B. Metternich
- Organisch Chemisches Institut; Westfälische Wilhelms-Universität Münster; Corrensstraße 40 48149 Münster Germany
- Current address: Department of Chemistry and Chemical Biology; Harvard University; 12 Oxford Street Cambridge MA 02138 USA
| | - Constantin G. Daniliuc
- Organisch Chemisches Institut; Westfälische Wilhelms-Universität Münster; Corrensstraße 40 48149 Münster Germany
| | - Allan J. B. Watson
- EASTCHEM School of Chemistry; University of St Andrews, North Haugh; St Andrews, Fife UK
| | - Ryan Gilmour
- Organisch Chemisches Institut; Westfälische Wilhelms-Universität Münster; Corrensstraße 40 48149 Münster Germany
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22
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Skubi KL, Kidd JB, Jung H, Guzei IA, Baik MH, Yoon TP. Enantioselective Excited-State Photoreactions Controlled by a Chiral Hydrogen-Bonding Iridium Sensitizer. J Am Chem Soc 2017; 139:17186-17192. [PMID: 29087702 DOI: 10.1021/jacs.7b10586] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Stereochemical control of electronically excited states is a long-standing challenge in photochemical synthesis, and few catalytic systems that produce high enantioselectivities in triplet-state photoreactions are known. We report herein an exceptionally effective chiral photocatalyst that recruits prochiral quinolones using a series of hydrogen-bonding and π-π interactions. The organization of these substrates within the chiral environment of the transition-metal photosensitizer leads to efficient Dexter energy transfer and effective stereoinduction. The relative insensitivity of these organometallic chromophores toward ligand modification enables the optimization of this catalyst structure for high enantiomeric excess at catalyst loadings as much as 100-fold lower than the optimal conditions reported for analogous chiral organic photosensitizers.
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Affiliation(s)
- Kazimer L Skubi
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Jesse B Kidd
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Hoimin Jung
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS) , Daejeon 34141, Republic of Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141, Republic of Korea
| | - Ilia A Guzei
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Mu-Hyun Baik
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS) , Daejeon 34141, Republic of Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141, Republic of Korea
| | - Tehshik P Yoon
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
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23
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Edtmüller V, Pöthig A, Bach T. Enantioselective photocyclisation reactions of 2-aryloxycyclohex-2-enones mediated by a chiral copper-bisoxazoline complex. Tetrahedron 2017. [DOI: 10.1016/j.tet.2017.05.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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24
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Miyabe H. Unique Strategies for Controlling Enantioselective Stereochemistry of Cyclizations via Radical Intermediates. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Hideto Miyabe
- School of Pharmacy; Hyogo University of Health Sciences; 650-8530 Minatojima, Chuo-ku Kobe Japan
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25
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Brenninger C, Pöthig A, Bach T. Brønsted Acid Catalysis in Visible-Light-Induced [2+2] Photocycloaddition Reactions of Enone Dithianes. Angew Chem Int Ed Engl 2017; 56:4337-4341. [PMID: 28319302 PMCID: PMC5396283 DOI: 10.1002/anie.201700837] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 02/09/2017] [Indexed: 12/15/2022]
Abstract
1,3-Dithiane-protected enones (enone dithianes) were found to undergo an intramolecular [2+2] photocycloaddition under visible-light irradiation (λ=405 nm) in the presence of a Brønsted acid (7.5-10 mol %). Key to the success of the reaction is presumably the formation of colored thionium ions, which are intermediates of the catalytic cycle. Cyclobutanes were thus obtained in very good yields (78-90 %). It is also shown that the dithiane moiety can be reductively or oxidatively removed without affecting the photochemically constructed ring skeleton.
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Affiliation(s)
- Christoph Brenninger
- Department Chemie and Catalysis Research Center (CRC)Technische Universität MünchenLichtenbergstrasse 485747GarchingGermany
| | - Alexander Pöthig
- Department Chemie and Catalysis Research Center (CRC)Technische Universität MünchenLichtenbergstrasse 485747GarchingGermany
| | - Thorsten Bach
- Department Chemie and Catalysis Research Center (CRC)Technische Universität MünchenLichtenbergstrasse 485747GarchingGermany
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26
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Brenninger C, Pöthig A, Bach T. Brønsted-Säure-Katalyse der [2+2]-Photocycloaddition von Enondithianen bei Bestrahlung mit sichtbarem Licht. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201700837] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Christoph Brenninger
- Department Chemie und Catalysis Research Center (CRC); Technische Universität München; Lichtenbergstr. 4 85747 Garching Deutschland
| | - Alexander Pöthig
- Department Chemie und Catalysis Research Center (CRC); Technische Universität München; Lichtenbergstr. 4 85747 Garching Deutschland
| | - Thorsten Bach
- Department Chemie und Catalysis Research Center (CRC); Technische Universität München; Lichtenbergstr. 4 85747 Garching Deutschland
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27
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Hölzl A, Bach T. Structural rearrangement cascade initiated by irradiation of but-3-enyl orotates. J Photochem Photobiol A Chem 2016. [DOI: 10.1016/j.jphotochem.2015.09.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Poplata S, Tröster A, Zou YQ, Bach T. Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions. Chem Rev 2016; 116:9748-815. [PMID: 27018601 PMCID: PMC5025837 DOI: 10.1021/acs.chemrev.5b00723] [Citation(s) in RCA: 690] [Impact Index Per Article: 86.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Indexed: 11/30/2022]
Abstract
The [2 + 2] photocycloaddition is undisputedly the most important and most frequently used photochemical reaction. In this review, it is attempted to cover all recent aspects of [2 + 2] photocycloaddition chemistry with an emphasis on synthetically relevant, regio-, and stereoselective reactions. The review aims to comprehensively discuss relevant work, which was done in the field in the last 20 years (i.e., from 1995 to 2015). Organization of the data follows a subdivision according to mechanism and substrate classes. Cu(I) and PET (photoinduced electron transfer) catalysis are treated separately in sections 2 and 4 , whereas the vast majority of photocycloaddition reactions which occur by direct excitation or sensitization are divided within section 3 into individual subsections according to the photochemically excited olefin.
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Affiliation(s)
- Saner Poplata
- Department Chemie and Catalysis
Research Center (CRC), Technische Universität
München, D-85747 Garching, Germany
| | - Andreas Tröster
- Department Chemie and Catalysis
Research Center (CRC), Technische Universität
München, D-85747 Garching, Germany
| | - You-Quan Zou
- Department Chemie and Catalysis
Research Center (CRC), Technische Universität
München, D-85747 Garching, Germany
| | - Thorsten Bach
- Department Chemie and Catalysis
Research Center (CRC), Technische Universität
München, D-85747 Garching, Germany
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29
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Wang H, Fang WH, Chen X. Mechanism of the Enantioselective Intramolecular [2 + 2] Photocycloaddition Reaction of Coumarin Catalyzed by a Chiral Lewis Acid: Comparison with Enone Substrates. J Org Chem 2016; 81:7093-101. [DOI: 10.1021/acs.joc.6b00980] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hongjuan Wang
- Key Laboratory of Theoretical
and Computational Photochemistry of Ministry of Education, Department
of Chemistry, Beijing Normal University, Xin-wai-da-jie 19, Beijing 100875, People’s Republic of China
| | - Wei-Hai Fang
- Key Laboratory of Theoretical
and Computational Photochemistry of Ministry of Education, Department
of Chemistry, Beijing Normal University, Xin-wai-da-jie 19, Beijing 100875, People’s Republic of China
| | - Xuebo Chen
- Key Laboratory of Theoretical
and Computational Photochemistry of Ministry of Education, Department
of Chemistry, Beijing Normal University, Xin-wai-da-jie 19, Beijing 100875, People’s Republic of China
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30
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Tröster A, Alonso R, Bauer A, Bach T. Enantioselective Intermolecular [2 + 2] Photocycloaddition Reactions of 2(1H)-Quinolones Induced by Visible Light Irradiation. J Am Chem Soc 2016; 138:7808-11. [PMID: 27268908 PMCID: PMC4929526 DOI: 10.1021/jacs.6b03221] [Citation(s) in RCA: 191] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
![]()
In the presence of
a chiral thioxanthone catalyst (10 mol %) the
title compounds underwent a clean intermolecular [2 + 2] photocycloaddition
with electron-deficient olefins at λ = 419 nm. The reactions
not only proceeded with excellent regio- and diastereoselectivity
but also delivered the respective cyclobutane products with significant
enantiomeric excess (up to 95% ee). Key to the success
of the reactions is a two-point hydrogen bonding between quinolone
and catalyst enabling efficient energy transfer and high enantioface
differentiation. Preliminary work indicated that solar irradiation
can be used for this process and that the substrate scope can be further
expanded to isoquinolones.
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Affiliation(s)
- Andreas Tröster
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Rafael Alonso
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Andreas Bauer
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Thorsten Bach
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
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31
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Mayr F, Brimioulle R, Bach T. A Chiral Thiourea as a Template for Enantioselective Intramolecular [2 + 2] Photocycloaddition Reactions. J Org Chem 2016; 81:6965-71. [PMID: 27258626 PMCID: PMC4994062 DOI: 10.1021/acs.joc.6b01039] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
A chiral
(1R,2R)-diaminocyclohexane-derived
bisthiourea was found to exhibit a significant asymmetric induction
in the intramolecular [2 + 2] photocycloaddition of 2,3-dihydropyridone-5-carboxylates.
Under optimized conditions, the reaction was performed with visible
light employing 10 mol % of thioxanthone as triplet sensitizer. Due
to the different electronic properties of its carbonyl oxygen atoms,
a directed binding of the substrate to the template is possible, which
in turn enables an efficient enantioface differentiation.
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Affiliation(s)
- Florian Mayr
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Richard Brimioulle
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Thorsten Bach
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
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32
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Amador AG, Sherbrook EM, Yoon TP. Enantioselective Photocatalytic [3 + 2] Cycloadditions of Aryl Cyclopropyl Ketones. J Am Chem Soc 2016; 138:4722-5. [PMID: 27015009 DOI: 10.1021/jacs.6b01728] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Control of stereochemistry in photocycloaddition reactions remains a substantial challenge; almost all successful catalytic examples to date have involved [2 + 2] photocycloadditions of enones. We report a method for the asymmetric [3 + 2] photocycloaddition of aryl cyclopropyl ketones that enables the enantiocontrolled construction of densely substituted cyclopentane structures not synthetically accessible using other catalytic methods. These results show that the dual-catalyst strategy developed in our laboratory broadens synthetic chemists' access to classes of photochemical cycloadditions that have not previously been feasible in enantioselective form.
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Affiliation(s)
- Adrian G Amador
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Evan M Sherbrook
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Tehshik P Yoon
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
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33
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Lenhart D, Bauer A, Pöthig A, Bach T. Enantioselective Visible-Light-Induced Radical-Addition Reactions to 3-Alkylidene Indolin-2-ones. Chemistry 2016; 22:6519-23. [PMID: 26946444 DOI: 10.1002/chem.201600600] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Indexed: 11/10/2022]
Abstract
The title compounds underwent a facile and high-yielding addition reaction (19 examples, 66-99% yield) with various N-(trimethylsilyl)methyl-substituted amines upon irradiation with visible light and catalysis by a metal complex. If the alkylidene substituent is non-symmetric and if the reaction is performed in the presence of a chiral hydrogen-bonding template, products are obtained with significant enantioselectivity (58-72% ee) as a mixture of diastereoisomers. Mechanistic studies suggest a closed catalytic cycle for the photoactive metal complex. However, the silyl transfer from the amine occurs not only to the product, but also to the substrate, and interferes with the desired chirality transfer.
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Affiliation(s)
- Dominik Lenhart
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstrasse 4, 85747, Garching, Germany), Fax
| | - Andreas Bauer
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstrasse 4, 85747, Garching, Germany), Fax
| | - Alexander Pöthig
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstrasse 4, 85747, Garching, Germany), Fax
| | - Thorsten Bach
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstrasse 4, 85747, Garching, Germany), Fax.
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34
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Sequential oxidation/thermal induced intramolecular [2+2] cycloaddition of propynol-vinylidenecyclopropanes: access to novel cyclobutene-containing spiro[2.3]hexenes. Tetrahedron 2016. [DOI: 10.1016/j.tet.2015.11.064] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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35
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Wang H, Cao X, Chen X, Fang W, Dolg M. Regulatory Mechanism of the Enantioselective Intramolecular Enone [2+2] Photocycloaddition Reaction Mediated by a Chiral Lewis Acid Catalyst Containing Heavy Atoms. Angew Chem Int Ed Engl 2015; 54:14295-8. [PMID: 26437573 DOI: 10.1002/anie.201505931] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 08/14/2015] [Indexed: 11/11/2022]
Abstract
The asymmetric catalysis of the intramolecular enone [2+2] photocycloaddition has been subject of extensive experimental studies, however theoretical insight to its regulatory mechanism is still sparse. Accurate quantum chemical calculations at the CASPT2//CASSCF level of theory associated with energy-consistent relativistic pseudopotentials provide a basis for the first regulation theory that the enantioselective reaction is predominantly controlled by the presence of relativistic effects, that is, spin-orbit coupling resulting from heavy atoms in the chiral Lewis acid catalyst.
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Affiliation(s)
- Hongjuan Wang
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, Department of Chemistry, Beijing Normal University, Xin-wai-da-jie No. 19, Beijing 100875 (China)
| | - Xiaoyan Cao
- Theoretical Chemistry, University of Cologne, Greinstrasse 4, 50939 Cologne (Germany)
| | - Xuebo Chen
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, Department of Chemistry, Beijing Normal University, Xin-wai-da-jie No. 19, Beijing 100875 (China).
| | - Weihai Fang
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, Department of Chemistry, Beijing Normal University, Xin-wai-da-jie No. 19, Beijing 100875 (China)
| | - Michael Dolg
- Theoretical Chemistry, University of Cologne, Greinstrasse 4, 50939 Cologne (Germany).
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36
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Wang H, Cao X, Chen X, Fang W, Dolg M. Regulatory Mechanism of the Enantioselective Intramolecular Enone [2+2] Photocycloaddition Reaction Mediated by a Chiral Lewis Acid Catalyst Containing Heavy Atoms. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201505931] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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37
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Xu Y, Conner ML, Brown MK. Cyclobutane and cyclobutene synthesis: catalytic enantioselective [2+2] cycloadditions. Angew Chem Int Ed Engl 2015; 54:11918-28. [PMID: 26333192 DOI: 10.1002/anie.201502815] [Citation(s) in RCA: 218] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Indexed: 12/21/2022]
Abstract
Cyclobutanes and cyclobutenes are important structural motifs found in numerous biologically significant molecules, and they are useful intermediates for chemical synthesis. Consequently, [2+2] cycloadditions to access cyclobutanes and cyclobutenes have been established to be particularly useful transformations. Within the last 10 years, an increase in the frequency of publications for catalytic enantioselective [2+2] cycloadditions has occurred. These reactions provide access to a wide array of enantiomerically enriched chemical diversity that was not previously attainable. Described in this review are the advances made in catalytic enantioselective [2+2] cycloadditions to access cyclobutanes and cyclobutenes.
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Affiliation(s)
- Yao Xu
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, IN 47405 (USA)
| | - Michael L Conner
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, IN 47405 (USA)
| | - M Kevin Brown
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, IN 47405 (USA).
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38
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Xu Y, Conner ML, Brown MK. Synthese von Cyclobutanen und Cyclobutenen: katalytische enantioselektive [2+2]-Cycloadditionen. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201502815] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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39
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Metternich JB, Gilmour R. A Bio-Inspired, Catalytic E → Z Isomerization of Activated Olefins. J Am Chem Soc 2015; 137:11254-7. [PMID: 26310905 DOI: 10.1021/jacs.5b07136] [Citation(s) in RCA: 252] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Herein, Nature's flavin-mediated activation of complex (poly)enes has been translated to a small molecule paradigm culminating in a highly (Z)-selective, catalytic isomerization of activated olefins using (-)-riboflavin (up to 99:1 Z/E). In contrast to the prominent Z → E isomerization of the natural system, it was possible to invert the directionality of the isomerization (E → Z) by simultaneously truncating the retinal scaffold, and introducing a third olefin substituent to augment A1,3-strain upon isomerization. Consequently, conjugation is reduced in the product chromophore leading to a substrate/product combination with discrete photophysical signatures. The operationally simple isomerization protocol has been applied to a variety of enone-derived substrates and showcased in the preparation of the medically relevant 4-substituted coumarin scaffold. A correlation of sensitizer triplet energy (ET) and reaction efficiency, together with the study of additive effects and mechanistic probes, is consistent with a triplet energy transfer mechanism.
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Affiliation(s)
- Jan B Metternich
- Institute for Organic Chemistry, Westfälische Wilhelms-Universität Münster , Corrensstrasse 40, 48149 Münster, Germany
| | - Ryan Gilmour
- Institute for Organic Chemistry, Westfälische Wilhelms-Universität Münster , Corrensstrasse 40, 48149 Münster, Germany
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Walaszek DJ, Rybicka-Jasińska K, Smoleń S, Karczewski M, Gryko D. Mechanistic Insights into Enantioselective CH Photooxygenation of AldehydesviaEnamine Catalysis. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500056] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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41
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Harder M, Carnero Corrales MA, Trapp N, Kuhn B, Diederich F. Rebek Imide Platforms as Model Systems for the Investigation of Weak Intermolecular Interactions. Chemistry 2015; 21:8455-63. [DOI: 10.1002/chem.201500462] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Indexed: 11/09/2022]
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42
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Brimioulle R, Bauer A, Bach T. Enantioselective Lewis Acid Catalysis in Intramolecular [2 + 2] Photocycloaddition Reactions: A Mechanistic Comparison between Representative Coumarin and Enone Substrates. J Am Chem Soc 2015; 137:5170-6. [PMID: 25806816 DOI: 10.1021/jacs.5b01740] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The intramolecular [2 + 2] photocycloaddition of three 4-(alk-4-enyl)coumarins and three 1-(alk-4-enoyl)-2,3-dihydropyridones was studied in the absence and in the presence of Lewis acids (irradiation wavelength λ = 366 nm). Spectral and kinetic data were collected for the respective parent compounds with a pent-4-enyl and a pent-4-enoyl chain. For the substrates with a methyl group in cis- or trans-position of the terminal alkene carbon atom (hex-4-enyl and hex-4-enoyl substitution), the stereochemical outcome of the [2 + 2] photocycloaddition was investigated. The mechanistic course of the uncatalyzed coumarin reactions was found to be a singlet pathway, whereas Lewis acid-catalyzed reactions proceeded with higher reaction rates in the triplet manifold. Contrary to that, the dihydropyridones underwent a fast triplet reaction in the absence of the Lewis acid. In the presence of a chiral Lewis acid the reactions slowed down but, due to the high extinction coefficient of the Lewis acid/dihydropyridone complexes at λ = 366 nm, still resulted in high enantioselectivity.
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Affiliation(s)
- Richard Brimioulle
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, D-85747 Garching, Germany
| | - Andreas Bauer
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, D-85747 Garching, Germany
| | - Thorsten Bach
- Department Chemie and Catalysis Research Center (CRC), Technische Universität München, D-85747 Garching, Germany
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Conner ML, Xu Y, Brown MK. Catalytic enantioselective allenoate-alkene [2 + 2] cycloadditions. J Am Chem Soc 2015; 137:3482-5. [PMID: 25756948 DOI: 10.1021/jacs.5b00563] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Catalytic enantioselective [2 + 2] cycloadditions between allenoates and alkenes is disclosed. The method functions well for a variety of alkenes, and the products are generated with excellent levels of enantioselectivity. One of the most significant aspects of the present method is that unactivated alkenes are suitable substrates for this method, which is distinctly different from nearly all other catalytic enantioselective [2 + 2] cycloaddition methods.
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Affiliation(s)
- Michael L Conner
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Yao Xu
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - M Kevin Brown
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, United States
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Brimioulle R, Lenhart D, Maturi MM, Bach T. Enantioselective Catalysis of Photochemical Reactions. Angew Chem Int Ed Engl 2015; 54:3872-90. [DOI: 10.1002/anie.201411409] [Citation(s) in RCA: 459] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Indexed: 01/07/2023]
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45
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Brimioulle R, Lenhart D, Maturi MM, Bach T. Enantioselektive Katalyse photochemischer Reaktionen. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201411409] [Citation(s) in RCA: 153] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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46
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Brimioulle R, Bach T. [2+2]-Photocycloaddition von 3-Alkenyloxy-2-cycloalkenonen: enantioselektive Lewis-Säure-Katalyse und Ringerweiterung. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201407832] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Brimioulle R, Bach T. [2+2] Photocycloaddition of 3-Alkenyloxy-2-cycloalkenones: Enantioselective Lewis Acid Catalysis and Ring Expansion. Angew Chem Int Ed Engl 2014; 53:12921-4. [DOI: 10.1002/anie.201407832] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Indexed: 11/10/2022]
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48
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Fort DA, Woltering TJ, Alker AM, Bach T. An Intramolecular [2 + 2] Photocycloaddition Approach to Conformationally Restricted Bis-Pyrrolidines. J Org Chem 2014; 79:7152-61. [DOI: 10.1021/jo501302f] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Diego A. Fort
- Lehrstuhl
für Organische Chemie I, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany
| | | | | | - Thorsten Bach
- Lehrstuhl
für Organische Chemie I, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany
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Schnapperelle I, Bach T. Modular Synthesis of Phenanthro[9,10-c]thiophenes by a Sequence of CH Activation, Suzuki Cross-Coupling and Photocyclization Reactions. Chemistry 2014; 20:9725-32. [DOI: 10.1002/chem.201402765] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Indexed: 01/21/2023]
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50
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Maturi MM, Bach T. Enantioselective Catalysis of the Intermolecular [2+2] Photocycloaddition between 2-Pyridones and Acetylenedicarboxylates. Angew Chem Int Ed Engl 2014; 53:7661-4. [DOI: 10.1002/anie.201403885] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Indexed: 11/12/2022]
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