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Bryden MA, Crovini E, Comerford T, Studer A, Zysman-Colman E. Organic Donor-Acceptor Thermally Activated Delayed Fluorescence Photocatalysts in the Photoinduced Dehalogenation of Aryl Halides. Angew Chem Int Ed Engl 2024; 63:e202405081. [PMID: 38600037 DOI: 10.1002/anie.202405081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/02/2024] [Accepted: 04/10/2024] [Indexed: 04/12/2024]
Abstract
We report a family of donor-acceptor thermally activated delayed fluorescent (TADF) compounds based on derivatives of DMAC-TRZ, that are strongly photoreducing. Both Eox and thus E*ox could be tuned via substitution of the DMAC donor with a Hammett series of p-substituted phenyl moieties while Ered remained effectively constant. These compounds were assessed in the photoinduced dehalogenation of aryl halides, and analogues bearing electron withdrawing groups were found to produce the highest yields. Substrates of up to Ered=-2.72 V could be dehalogenated at low PC loading (1 mol %) and under air, conditions much milder than previously reported for this reaction. Spectroscopic and chemical studies demonstrate that all PCs, including literature reference PCs, photodegrade, and that it is these photodegradation products that are responsible for the reactivity.
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Affiliation(s)
- Megan Amy Bryden
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, United Kingdom
| | - Ettore Crovini
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, United Kingdom
| | - Thomas Comerford
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, United Kingdom
| | - Armido Studer
- Organisch-Chemisches Institut, University of Münster, Corrensstaße 40, 48149, Münster, Germany
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, United Kingdom
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2
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Piejko M, Moran J, Lebœuf D. Difunctionalization Processes Enabled by Hexafluoroisopropanol. ACS ORGANIC & INORGANIC AU 2024; 4:287-300. [PMID: 38855339 PMCID: PMC11157514 DOI: 10.1021/acsorginorgau.3c00067] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 06/11/2024]
Abstract
In the past 5 years, hexafluoroisopropanol (HFIP) has been used as a unique solvent or additive to enable challenging transformations through substrate activation and stabilization of reactive intermediates. In this Review, we aim at describing difunctionalization processes which were unlocked when HFIP was involved. Specifically, we focus on cyclizations and additions to alkenes, alkynes, epoxides, and carbonyls that introduce a wide range of functional groups of interest.
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Affiliation(s)
- Maciej Piejko
- Institut
de Science et d’Ingénierie Supramoléculaires
(ISIS), CNRS UMR 7006, Université
de Strasbourg, 8 Allée Gaspard Monge, 67000 Strasbourg, France
| | - Joseph Moran
- Institut
de Science et d’Ingénierie Supramoléculaires
(ISIS), CNRS UMR 7006, Université
de Strasbourg, 8 Allée Gaspard Monge, 67000 Strasbourg, France
- Department
of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- Institut
Universitaire de France (IUF), 75005 Paris, France
| | - David Lebœuf
- Institut
de Science et d’Ingénierie Supramoléculaires
(ISIS), CNRS UMR 7006, Université
de Strasbourg, 8 Allée Gaspard Monge, 67000 Strasbourg, France
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3
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Ando H, Takamura H, Kadota I, Tanaka K. Strongly reducing helical phenothiazines as recyclable organophotoredox catalysts. Chem Commun (Camb) 2024; 60:4765-4768. [PMID: 38529587 DOI: 10.1039/d4cc00904e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
Recyclable phenothiazine organophotoredox catalysts (PTHS 1-3, E1/2ox* = -2.34 to -2.40 V vs. SCE) have been developed. When the recycling performance was evaluated, PTHS-1 could be recovered at least four times without loss of its catalytic activity. These recyclable organophotoredox catalysts represent a promising tool for sustainable organic synthesis.
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Affiliation(s)
- Haru Ando
- Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-Naka, Kitaku, Okayama 700-8530, Japan.
| | - Hiroyoshi Takamura
- Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-Naka, Kitaku, Okayama 700-8530, Japan.
| | - Isao Kadota
- Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-Naka, Kitaku, Okayama 700-8530, Japan.
| | - Kenta Tanaka
- Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-Naka, Kitaku, Okayama 700-8530, Japan.
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4
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Cuadros S, Paut J, Anselmi E, Dagousset G, Magnier E, Dell'Amico L. Light-Driven Synthesis and Functionalization of Bicycloalkanes, Cubanes and Related Bioisosteres. Angew Chem Int Ed Engl 2024; 63:e202317333. [PMID: 38179801 DOI: 10.1002/anie.202317333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/02/2024] [Accepted: 01/03/2024] [Indexed: 01/06/2024]
Abstract
Bicycloalkanes, cubanes and their structural analogues have emerged as bioisosteres of (hetero)arenes. To meet increasing demand, the chemical community has developed a plethora of novel synthetic methods. In this review, we assess the progress made in the field of light-driven construction and functionalization of such relevant molecules. We have focused on diverse structural targets, as well as on reaction processes giving access to: (i) [1.1.1]-bicyclopentanes (BCPs); (ii) [2.2.1]-bicyclohexanes (BCHs); (iii) [3.1.1]-bicycloheptanes (BCHeps); and (iv) cubanes; as well as other structurally related scaffolds. Finally, future perspectives dealing with the identification of novel reaction manifolds to access new functionalized bioisosteric units are discussed.
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Affiliation(s)
- Sara Cuadros
- Department of Chemical Sciences, University of Padova, Via Francesco Marzolo 1, 35131, Padova, Italy
| | - Julien Paut
- Department of Chemical Sciences, University of Padova, Via Francesco Marzolo 1, 35131, Padova, Italy
- Institut Lavoisier de Versailles, University of Paris-Saclay, 45 Avenue des Etats-Unis, 78035, Versailles, France
| | - Elsa Anselmi
- Institut Lavoisier de Versailles, University of Paris-Saclay, 45 Avenue des Etats-Unis, 78035, Versailles, France
- Université de Tours, Faculté des Sciences et Techniques, 37200, Tours, France
| | - Guillaume Dagousset
- Institut Lavoisier de Versailles, University of Paris-Saclay, 45 Avenue des Etats-Unis, 78035, Versailles, France
| | - Emmanuel Magnier
- Institut Lavoisier de Versailles, University of Paris-Saclay, 45 Avenue des Etats-Unis, 78035, Versailles, France
| | - Luca Dell'Amico
- Department of Chemical Sciences, University of Padova, Via Francesco Marzolo 1, 35131, Padova, Italy
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5
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Karak P, Moitra T, Banerjee A, Ruud K, Chakrabarti S. Accidental triplet harvesting in donor-acceptor dyads with low spin-orbit coupling. Phys Chem Chem Phys 2024; 26:5344-5355. [PMID: 38268441 DOI: 10.1039/d3cp04904c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
We present an accidental mechanism for efficient intersystem crossing (ISC) between singlet and triplet states with low spin-orbit coupling (SOC) in molecules having donor-acceptor (D-A) moieties separated by a Sigma bond. Our study shows that SOC between the lowest singlet excited state and the higher-lying triplet states, together with nuclear motion-driven coupling of this triplet state with lower-lying triplet states during the free rotation about a Sigma bond, is one of the possible ways to achieve the experimentally observed ISC rate for a class of D-A type photoredox catalysts. This mechanism is found to be the dominant contributor to the ISC process with the corresponding rate reaching a maximum at a dihedral angle in the range of 72°-78° between the D-A moieties of 10-(naphthalen-1-yl)-3,7-diphenyl-10H-phenoxazine and other molecules included in the study. We have further demonstrated that the same mechanism is operative in a specific spirobis[anthracene]dione molecule, where the D and A moieties are interlocked near to the optimal dihedral angle, indicating the plausible effectiveness of the proposed mechanism. The present finding is expected to have implications in strategies for the synthesis of new generations of triplet-harvesting organic molecules.
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Affiliation(s)
- Pijush Karak
- Department of Chemistry, University of Calcutta, 92 A.P.C Road, Kolkata - 700009, West Bengal, India.
| | - Torsha Moitra
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Tromsø - The Arctic University of Norway, 9037 Tromsø, Norway.
| | - Ambar Banerjee
- Department of Physics and Astronomy, X-ray Photon Science, Uppsala University, Ångströmlaboratoriet, Lägerhyddsvägen 1, 75120, Uppsala, Sweden.
| | - Kenneth Ruud
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Tromsø - The Arctic University of Norway, 9037 Tromsø, Norway.
- Norwegian Defence Research Establishment, P.O.Box 25, 2027 Kjeller, Norway
| | - Swapan Chakrabarti
- Department of Chemistry, University of Calcutta, 92 A.P.C Road, Kolkata - 700009, West Bengal, India.
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6
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Chen M, Cui Y, Chen X, Shang R, Zhang X. C-F bond activation enables synthesis of aryl difluoromethyl bicyclopentanes as benzophenone-type bioisosteres. Nat Commun 2024; 15:419. [PMID: 38199996 PMCID: PMC10781780 DOI: 10.1038/s41467-023-44653-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 12/22/2023] [Indexed: 01/12/2024] Open
Abstract
Bioisosteric design has become an essential approach in the development of drug molecules. Recent advancements in synthetic methodologies have enabled the rapid adoption of this strategy into drug discovery programs. Consequently, conceptionally innovative practices would be appreciated by the medicinal chemistry community. Here we report an expeditous synthetic method for synthesizing aryl difluoromethyl bicyclopentane (ADB) as a bioisostere of the benzophenone core. This approach involves the merger of light-driven C-F bond activation and strain-release chemistry under the catalysis of a newly designed N-anionic-based organic photocatalyst. This defluorinative coupling methodology enables the direct conversion of a wide variety of commercially available trifluoromethylaromatic C-F bonds (more than 70 examples) into the corresponding difluoromethyl bicyclo[1.1.1]pentanes (BCP) arenes/difluoromethyl BCP boronates in a single step. The strategy can also be applied to [3.1.1]and [4.1.1]propellane systems, providing access to analogues with different geometries. Moreover, we have successfully used this protocol to rapidly prepare ADB-substituted analogues of the bioactive molecule Adiporon. Biological testing has shown that the ADB scaffold has the potential to enhance the pharmacological properties of benzophenone-type drug candidates.
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Affiliation(s)
- Mingshuo Chen
- School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, 310024, Hangzhou, People's Republic of China
| | - Yuang Cui
- School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, 310024, Hangzhou, People's Republic of China
| | - Xiaoping Chen
- School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, 310024, Hangzhou, People's Republic of China
| | - Rui Shang
- Department of Chemistry, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Xiaheng Zhang
- School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, 310024, Hangzhou, People's Republic of China.
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7
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Weick F, Hagmeyer N, Giraud M, Dietzek-Ivanšić B, Wagenknecht HA. Reductive Activation of Aryl Chlorides by Tuning the Radical Cation Properties of N-Phenylphenothiazines as Organophotoredox Catalysts. Chemistry 2023; 29:e202302347. [PMID: 37589486 DOI: 10.1002/chem.202302347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/17/2023] [Accepted: 08/17/2023] [Indexed: 08/18/2023]
Abstract
Aryl chlorides as substrates for arylations present a particular challenge for photoredox catalytic activation due to their strong C(sp2 )-Cl bond and their strong reduction potential. Electron-rich N-phenylphenothiazines, as organophotoredox catalysts, are capable of cleaving aryl chlorides simply by photoinduced electron transfer without the need for an additional electrochemical activation setup or any other advanced photocatalysis technique. Due to the extremely strong reduction potential in the excited state of the N-phenylphenothiazines the substrate scope is high and includes aryl chlorides both with electron-withdrawing and electron-donating substituents. We evidence this reactivity for photocatalytic borylations and phosphonylations. Advanced time-resolved transient absorption spectroscopy in combination with electrochemistry was the key to elucidating and comparing the unusual photophysical properties not only of the N-phenylphenothiazines, but also of their cation radicals as the central intermediates in the photocatalytic cycle. The revealed photophysics allowed the excited-state and radical-cation properties to be fine-tuned by the molecular design of the N-phenylphenothiazines; this improved the photocatalytic activity.
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Affiliation(s)
- Fabian Weick
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Nina Hagmeyer
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstraße 4, 07743, Jena, Germany
| | - Madeleine Giraud
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Benjamin Dietzek-Ivanšić
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstraße 4, 07743, Jena, Germany
- Research Department Functional Interfaces, Leibniz Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745, Jena, Germany
| | - Hans-Achim Wagenknecht
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
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8
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Žurauskas J, Boháčová S, Wu S, Butera V, Schmid S, Domański M, Slanina T, Barham JP. Electron-Poor Acridones and Acridiniums as Super Photooxidants in Molecular Photoelectrochemistry by Unusual Mechanisms. Angew Chem Int Ed Engl 2023; 62:e202307550. [PMID: 37584300 DOI: 10.1002/anie.202307550] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/14/2023] [Accepted: 08/15/2023] [Indexed: 08/17/2023]
Abstract
Electron-deficient acridones and in situ generated acridinium salts are reported as potent, closed-shell photooxidants that undergo surprising mechanisms. When bridging acyclic triarylamine catalysts with a carbonyl group (acridones), this completely diverts their behavior away from open-shell, radical cationic, 'beyond diffusion' photocatalysis to closed-shell, neutral, diffusion-controlled photocatalysis. Brønsted acid activation of acridones dramatically increases excited state oxidation power (by +0.8 V). Upon reduction of protonated acridones, they transform to electron-deficient acridinium salts as even more potent photooxidants (*E1/2 =+2.56-3.05 V vs SCE). These oxidize even electron-deficient arenes where conventional acridinium salt photooxidants have thusfar been limited to electron-rich arenes. Surprisingly, upon photoexcitation these electron-deficient acridinium salts appear to undergo two electron reductive quenching to form acridinide anions, spectroscopically-detected as their protonated forms. This new behaviour is partly enabled by a catalyst preassembly with the arene, and contrasts to conventional SET reductive quenching of acridinium salts. Critically, this study illustrates how redox active chromophoric molecules initially considered photocatalysts can transform during the reaction to catalytically active species with completely different redox and spectroscopic properties.
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Affiliation(s)
- Jonas Žurauskas
- Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Soňa Boháčová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16000, Prague 6, Czech Republic
| | - Shangze Wu
- Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Valeria Butera
- Central European Institute of Technology, CEITEC, 61200 Brno (Czech Republic), Department of Science and Biological Chemical and Pharmaceutical Technologies, University of Palermo, 90128, Palermo, Italy
| | - Simon Schmid
- Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Michał Domański
- Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Tomáš Slanina
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16000, Prague 6, Czech Republic
| | - Joshua P Barham
- Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
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9
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Franceschi P, Rossin E, Goti G, Scopano A, Vega-Peñaloza A, Natali M, Singh D, Sartorel A, Dell'Amico L. A Proton-Coupled Electron Transfer Strategy to the Redox-Neutral Photocatalytic CO 2 Fixation. J Org Chem 2023; 88:6454-6464. [PMID: 36760023 DOI: 10.1021/acs.joc.2c02952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Herein, we report our study on the design and development of a novel photocarboxylation method. We have used an organic photoredox catalyst (PC, 4CzIPN) and differently substituted dihydropyridines (DHPs) in combination with an organic base (1,5,7-triazabicyclodec-5-ene, TBD) to access a proton-coupled electron transfer (PCET) based manifold. In depth mechanistic investigations merging experimental analysis (NMR, IR, cyclic voltammetry) and density-functional theory (DFT) calculations reveal the key activity of a H-bonding complex between the DHP and the base. The thermodynamic and kinetic benefits of the PCET mechanism allowed the implementation of a redox-neutral fixation process leading to synthetically relevant carboxylic acids (18 examples with isolated yields up to 75%) under very mild reaction conditions. Finally, diverse product manipulations were performed to demonstrate the synthetic versatility of the obtained products.
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Affiliation(s)
- Pietro Franceschi
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Elena Rossin
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Giulio Goti
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Angelo Scopano
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Alberto Vega-Peñaloza
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Mirco Natali
- Department of Chemical, Pharmaceutical, and Agricultural Sciences, University of Ferrara, Via L. Borsari 46, 44121 Ferrara, Italy
| | - Deepak Singh
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Andrea Sartorel
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Luca Dell'Amico
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
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