1
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Yan X, Pang Y, Zhou Y, Chang R, Ye J. Photochemical Deracemization of Lactams with Deuteration Enabled by Dual Hydrogen Atom Transfer. J Am Chem Soc 2024. [PMID: 39692147 DOI: 10.1021/jacs.4c14934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2024]
Abstract
Photochemical deracemization has emerged as one of the most straightforward approaches to access highly enantioenriched compounds in recent years. While excited-state events such as energy transfer, single electron transfer, and ligand-to-metal charge transfer have been leveraged to promote stereoablation, approaches relying on hydrogen atom transfer, which circumvent the limitations imposed by the triplet energy and redox potential of racemic substrates, remain underexplored. Conceptually, the most attractive method for tertiary stereocenter deracemization might be hydrogen atom abstraction followed by hydrogen atom donation. However, implementing such a strategy poses significant challenges, primarily because the enantioenriched products are also reactive if the chiral catalyst is unable to differentiate between the two enantiomers. Herein we report a distinct dual hydrogen atom transfer strategy for photochemical deracemization of δ- and γ-lactams, achieving high enantioenrichment and deuterium incorporation despite the inherent reactivity of the products. Mechanistic studies reveal that benzophenone enables nonselective hydrogen atom abstraction while a tetrapeptide-derived thiol dictates the enantioselectivity of the hydrogen atom donation step. More importantly, a pyridine-based alcohol was found to play crucial roles in facilitating the hydrogen atom abstraction as well as enhancing the enantioselectivity of the hydrogen atom donation step.
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Affiliation(s)
- Xiaoyu Yan
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yubing Pang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yutong Zhou
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Rui Chang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Juntao Ye
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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2
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Lunic D, Vystavkin N, Qin J, Teskey CJ. Dual-Catalytic Structural Isomerisation as a Route to α-Arylated Ketones. Angew Chem Int Ed Engl 2024; 63:e202409388. [PMID: 38977417 DOI: 10.1002/anie.202409388] [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: 05/17/2024] [Revised: 07/05/2024] [Accepted: 07/08/2024] [Indexed: 07/10/2024]
Abstract
Isomerisation reactions provide streamlined routes to organic compounds which are otherwise hard to directly synthesise. The most common forms are positional, geometrical or stereochemical isomerisations which involve the relocation of a double bond or a change in relative location of groups in space. In contrast, far fewer examples of structural (or constitutional) isomerisation exist where the connectivity between atoms is altered. The development of platforms capable of such rearrangement poses a unique set of challenges because chemical bonds must be selectively cleaved, and new ones formed without overall addition or removal of atoms. Here, we show that a dual catalytic system can enable the structural isomerisation of readily available allylic alcohols into more challenging-to-synthesise α-arylated ketones via a H-atom transfer initiated semi-pinacol rearrangement. Key to our strategy is the combination of a cobalt catalyst and photocatalyst under reductive, protic conditions which allows intermediates to propagate catalytic turnover. By providing an unusual disconnection to structural motifs which are difficult to access through direct arylation, we anticipate inspiring other advanced catalytic isomerisation strategies that will further retrosynthetic logic for complex molecule synthesis.
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Affiliation(s)
- Danijela Lunic
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Nikita Vystavkin
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
- Institute of Organic Chemistry, TU Braunschweig, Hagenring 30, 38106, Braunschweig, Germany
| | - Jingyang Qin
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
- Institute of Organic Chemistry, TU Braunschweig, Hagenring 30, 38106, Braunschweig, Germany
| | - Christopher J Teskey
- Institute of Organic Chemistry, TU Braunschweig, Hagenring 30, 38106, Braunschweig, Germany
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3
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Tan CY, Hong S. Harnessing the potential of acyl triazoles in bifunctional cobalt-catalyzed radical cross-coupling reactions. Nat Commun 2024; 15:6965. [PMID: 39138198 PMCID: PMC11322283 DOI: 10.1038/s41467-024-51376-9] [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: 06/27/2024] [Accepted: 08/06/2024] [Indexed: 08/15/2024] Open
Abstract
Persistent radicals facilitate numerous selective radical coupling reactions. Here, we have identified acyl triazole as a new and versatile moiety for generating persistent radical intermediates through single-electron transfer processes. The efficient generation of these persistent radicals is facilitated by the formation of substrate-coordinated cobalt complexes, which subsequently engage in radical cross-coupling reactions. Remarkably, triazole-coordinated cobalt complexes exhibit metal-hydride hydrogen atom transfer (MHAT) capabilities with alkenes, enabling the efficient synthesis of diverse ketone products without the need for external ligands. By leveraging the persistent radical effect, this catalytic approach also allows for the development of other radical cross-coupling reactions with two representative radical precursors. The discovery of acyl triazoles as effective substrates for generating persistent radicals and as ligands for cobalt catalysis, combined with the bifunctional nature of the cobalt catalytic system, opens up new avenues for the design and development of efficient and sustainable organic transformations.
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Affiliation(s)
- Chang-Yin Tan
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Sungwoo Hong
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea.
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Korea.
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4
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Carder HM, Occhialini G, Bistoni G, Riplinger C, Kwan EE, Wendlandt AE. The sugar cube: Network control and emergence in stereoediting reactions. Science 2024; 385:456-463. [PMID: 39052778 DOI: 10.1126/science.adp2447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Accepted: 06/07/2024] [Indexed: 07/27/2024]
Abstract
Stereochemical editing strategies have recently enabled the transformation of readily accessible substrates into rare and valuable products. Typically, site selectivity is achieved by minimizing kinetic complexity by using protecting groups to suppress reactivity at undesired sites (substrate control) or by using catalysts with tailored shapes to drive reactivity at the desired site (catalyst control). We propose "network control," a contrasting paradigm that exploits hidden interactions between rate constants to greatly amplify modest intrinsic biases and enable precise multisite editing. When network control is applied to the photochemical isomerization of hexoses, six of the eight possible diastereomers can be selectively obtained. The amplification effect can be viewed as a mesoscale phenomenon between the limiting regimes of kinetic control in simple chemical systems and metabolic regulation in complex biological systems.
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Affiliation(s)
- Hayden M Carder
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Gino Occhialini
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Giovanni Bistoni
- Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123 Perugia, Italy
| | | | | | - Alison E Wendlandt
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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5
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Song C, Bai X, Li B, Dang Y, Yu S. Photoexcited Palladium-Catalyzed Deracemization of Allenes. J Am Chem Soc 2024. [PMID: 39024194 DOI: 10.1021/jacs.4c07126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
The different enantiomers of specific chiral molecules frequently exhibit disparate biological, physiological, or pharmacological properties. Therefore, the efficient synthesis of single enantiomers is of particular importance not only to the pharmaceutical sector but also to other industrial sectors, such as agrochemical and fine chemical industries. Deracemization, a process during which a racemic mixture is converted into a nonracemic product with 100% atom economy and theoretical yield, is the most straightforward method to access enantioenriched molecules but a challenging task due to a decrease in entropy and microscopic reversibility. Axially chiral allenes bear a distinctive structure of two orthogonal cumulative π-systems and are acknowledged as synthetically versatile synthons in organic synthesis. The selective creation of axially chiral allenes with high optical purity under mild reaction conditions has always been a very popular and hot topic in organic synthesis but remains challenging. Herein, a photoexcited palladium-catalyzed deracemization of nonprefunctionalized disubstituted allenes is disclosed. This method provides an efficient and economical strategy to accommodate a broad scope of allenes with good enantioselectivities and yields (53 examples, up to 96% yield and 95% ee). The use of a suitable chiral palladium complex with visible light irradiation is an essential factor in achieving this transformation. A metal-to-ligand charge transfer mechanism was proposed based on control experiments and density functional theory calculations. Quantum mechanical studies implicate dual modes of asymmetric induction behind our new protocol: (1) sterically controlled stereoselective binding of one allene enantiomer under the ground-state and (2) facile, noncovalent interaction-driven excited-state isomerization toward the opposite enantiomer. The success of this newly established photochemical deracemization strategy should provide inspiration for expansion to other multisubstituted allenes and will open up a new mode for enantioselective excited-state palladium catalysis.
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Affiliation(s)
- Changhua Song
- State Key Laboratory of Analytical Chemistry for Life Science, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xiangbin Bai
- State Key Laboratory of Analytical Chemistry for Life Science, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Bo Li
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University, Tianjin 300072, China
| | - Yanfeng Dang
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University, Tianjin 300072, China
| | - Shouyun Yu
- State Key Laboratory of Analytical Chemistry for Life Science, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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6
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Indurmuddam RR, Huang PC, Hong BC, Chien SY. Visible-Light-Photocatalyzed Self-Cyclopropanation Reactions of Dibenzoylmethanes for the Synthesis of Cyclopropanes. Org Lett 2024; 26:5752-5757. [PMID: 38949643 DOI: 10.1021/acs.orglett.4c01875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
A new self-cyclopropanation of 1,3-diphenylpropane-1,3-dione, leading to tetrasubstituted cyclopropane containing three contiguous stereogenic centers with high stereoselectivity, has been achieved through violet-light-emitting diode-irradiated photocatalysis, featuring both cycloaddition and a distinctive rearrangement. Diverging from conventional cyclopropanation pathways, this reaction yields a tetrasubstituted cyclopropane through unprecedented rearrangement and cascade reactions.
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Affiliation(s)
| | - Pei-Chi Huang
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chia-Yi 621, Taiwan ROC
| | - Bor-Cherng Hong
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chia-Yi 621, Taiwan ROC
| | - Su-Ying Chien
- Instrumentation Center, National Taiwan University, Taipei 106, Taiwan ROC
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7
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Lin A, Lee S, Knowles RR. Organic Synthesis Away from Equilibrium: Contrathermodynamic Transformations Enabled by Excited-State Electron Transfer. Acc Chem Res 2024; 57:1827-1838. [PMID: 38905487 DOI: 10.1021/acs.accounts.4c00227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/23/2024]
Abstract
ConspectusChemists have long been inspired by biological photosynthesis, wherein a series of excited-state electron transfer (ET) events facilitate the conversion of low energy starting materials such as H2O and CO2 into higher energy products in the form of carbohydrates and O2. While this model for utilizing light-driven charge transfer to drive catalytic reactions thermodynamically "uphill" has been extensively adapted for small molecule activation, molecular machines, photoswitches, and solar fuel chemistry, its application in organic synthesis has been less systematically developed. However, the potential benefits of these approaches are significant, both in enabling transformations that cannot be readily achieved using conventional thermal chemistry and in accessing distinct selectivity regimes that are uniquely enabled by excited-state mechanisms. In this Account, we present work from our group that highlights the ability of visible light photoredox catalysis to drive useful organic transformations away from their equilibrium positions, addressing a number of long-standing synthetic challenges.We first discuss how excited-state ET enabled the first general methods for the catalytic anti-Markovnikov hydroamination of unactivated alkenes with alkyl amines. In these reactions, an excited-state iridium(III) photocatalyst reversibly oxidizes secondary amine substrates to their corresponding aminium radical cations (ARCs). These electrophilic N-centered radicals can then react with olefins to furnish valuable tertiary amine products with complete anti-Markovnikov regioselectivity. Notably, some of these products are less thermodynamically stable than their corresponding amine and alkene starting materials. We next present a strategy for light-driven C-C bond cleavage within various aliphatic alcohols mediated by homolytic activation of alcohol O-H bonds by excited-state proton-coupled electron transfer (PCET). The resulting alkoxy radical intermediates then undergo C-C β-scission to ultimately provide isomeric linear carbonyl products that are often higher in energy than their cyclic alcohol precursors. Applications of this chemistry for the light-driven depolymerization of lignin biomass, commercial phenoxy resin, hydroxylated polyolefin derivatives, and thermoset polymers are presented as well. We then describe a method for the contrathermodynamic positional isomerization of highly substituted olefins by means of cooperative photoredox and chromium(II) catalysis. In this work, generation of an allylchromium(III) species that can undergo highly regioselective in situ protodemetalation enables access to a less substituted and thermodynamically less stable positional isomer. Product selectivity in this reaction is determined by the large differential in oxidation potentials between differently substituted olefin isomers. Lastly, we discuss a light-driven deracemization reaction developed in collaboration with the Miller group, wherein a racemic urea substrate undergoes spontaneous optical enrichment upon visible light irradiation in the presence of an iridium(III) chromophore, a chiral Brønsted base, and a chiral peptide thiol. Excellent levels of enantioselectivity are achieved via sequential and synergistic proton transfer (PT) and H atom transfer (HAT) steps. Taken together, these examples highlight the ability of excited-state ET events to enable access to nonequilibrium product distributions across a wide range of catalytic, redox-neutral transformations in which photons are the only stoichiometric reagents.
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Affiliation(s)
- Angela Lin
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Sumin Lee
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Robert R Knowles
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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8
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Mendel M, Karl TM, Hamm J, Kaldas SJ, Sperger T, Mondal B, Schoenebeck F. Dynamic stereomutation of vinylcyclopropanes with metalloradicals. Nature 2024; 631:80-86. [PMID: 38898284 PMCID: PMC11222138 DOI: 10.1038/s41586-024-07555-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 05/10/2024] [Indexed: 06/21/2024]
Abstract
The ever increasing demands for greater sustainability and lower energy usage in chemical processes call for fundamentally new approaches and reactivity principles. In this context, the pronounced prevalence of odd-oxidation states in less precious metals bears untapped potential for fundamentally distinct reactivity modes via metalloradical catalysis1-3. Contrary to the well-established reactivity paradigm that organic free radicals, upon addition to a vinylcyclopropane, lead to rapid ring opening under strain release-a transformation that serves widely as a mechanistic probe (radical clock)4 for the intermediacy of radicals5-we herein show that a metal-based radical, that is, a Ni(I) metalloradical, triggers reversible cis/trans isomerization instead of opening. The isomerization proceeds under chiral inversion and, depending on the substitution pattern, occurs at room temperature in less than 5 min, requiring solely the addition of the non-precious catalyst. Our combined computational and experimental mechanistic studies support metalloradical catalysis as origin of this profound reactivity, rationalize the observed stereoinversion and reveal key reactivity features of the process, including its reversibility. These insights enabled the iterative thermodynamic enrichment of enantiopure cis/trans mixtures towards a single diastereomer through multiple Ni(I) catalysis rounds and also extensions to divinylcyclopropanes, which constitute strategic motifs in natural product- and total syntheses6. While the trans-isomer usually requires heating at approximately 200 °C to trigger thermal isomerization under racemization to cis-divinylcyclopropane, which then undergoes facile Cope-type rearrangement, the analogous contra-thermodynamic process is herein shown to proceed under Ni(I) metalloradical catalysis under mild conditions without any loss of stereochemical integrity, enabling a mild and stereochemically pure access to seven-membered rings, fused ring systems and spirocycles.
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Affiliation(s)
- Marvin Mendel
- Institute of Organic Chemistry, RWTH Aachen University, Aachen, Germany
| | - Teresa M Karl
- Institute of Organic Chemistry, RWTH Aachen University, Aachen, Germany
| | - Jegor Hamm
- Institute of Organic Chemistry, RWTH Aachen University, Aachen, Germany
| | - Sherif J Kaldas
- Institute of Organic Chemistry, RWTH Aachen University, Aachen, Germany
| | - Theresa Sperger
- Institute of Organic Chemistry, RWTH Aachen University, Aachen, Germany
| | - Bhaskar Mondal
- Institute of Organic Chemistry, RWTH Aachen University, Aachen, Germany
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9
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Schlosser L, Rana D, Pflüger P, Katzenburg F, Glorius F. EnTdecker - A Machine Learning-Based Platform for Guiding Substrate Discovery in Energy Transfer Catalysis. J Am Chem Soc 2024; 146:13266-13275. [PMID: 38695558 DOI: 10.1021/jacs.4c01352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Due to the magnitude of chemical space, the discovery of novel substrates in energy transfer (EnT) catalysis remains a daunting task. Experimental and computational strategies to identify compounds that successfully undergo EnT-mediated reactions are limited by their time and cost efficiency. To accelerate the discovery process in EnT catalysis, we herein present the EnTdecker platform, which facilitates the large-scale virtual screening of potential substrates using machine-learning (ML) based predictions of their excited state properties. To achieve this, a data set is created containing more than 34,000 molecules aiming to cover a vast fraction of synthetically relevant compound space for EnT catalysis. Using this data predictive models are trained, and their aptitude for an in-lab application is demonstrated by rediscovering successful substrates from literature as well as experimental validation through luminescence-based screening. By reducing the computational effort needed to obtain excited state properties, the EnTdecker platform represents a tool to efficiently guide substrate selection and increase the experimental success rate for EnT catalysis. Moreover, through an easy-to-use web application, EnTdecker is made publicly accessible under entdecker.uni-muenster.de.
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Affiliation(s)
- Leon Schlosser
- Organisch-Chemisches Institut, University of Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Debanjan Rana
- Organisch-Chemisches Institut, University of Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Philipp Pflüger
- Organisch-Chemisches Institut, University of Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Felix Katzenburg
- Organisch-Chemisches Institut, University of Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Frank Glorius
- Organisch-Chemisches Institut, University of Münster, Corrensstraße 36, 48149 Münster, Germany
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10
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Wang Y, Fan S, Tang X. Nucleophilic Organocatalyst for Photochemical Carbon Radical Generation via S N2 Substitution. Org Lett 2024; 26:4002-4007. [PMID: 38691539 DOI: 10.1021/acs.orglett.4c01278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
Photochemical generation of radicals is a powerful way to construct various molecules. But most of these methods rely on initiators or the redox properties of radical precursors. Herein, we report a photochemical organic catalyst that reacts with benzyl halide to generate carbon radical via an SN2 pathway. This nucleophilic catalyst can be easily prepared and is bench-stable. The SN2 process does not rely on the redox properties of halides, showing potential synthetic utility. Control experiments and UV-vis spectroscopic analysis indicate that the SN2 substitution adduct is the key intermediate.
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Affiliation(s)
- Yuzhuo Wang
- Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Shiwen Fan
- Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Xinjun Tang
- Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
- Zhejiang Institute, China University of Geosciences, Hangzhou 311305, China
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11
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Wenzel JO, Werner J, Allgaier A, van Slageren J, Fernández I, Unterreiner AN, Breher F. Visible-Light Activation of Diorganyl Bis(pyridylimino) Isoindolide Aluminum(III) Complexes and Their Organometallic Radical Reactivity. Angew Chem Int Ed Engl 2024; 63:e202402885. [PMID: 38511969 DOI: 10.1002/anie.202402885] [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: 02/08/2024] [Revised: 03/14/2024] [Accepted: 03/14/2024] [Indexed: 03/22/2024]
Abstract
We report on the synthesis and characterization of a series of (mostly) air-stable diorganyl bis(pyridylimino) isoindolide (BPI) aluminum complexes and their chemistry upon visible-light excitation. The redox non-innocent BPI pincer ligand allows for efficient charge transfer homolytic processes of the title compounds. This makes them a universal platform for the generation of carbon-centered radicals. The photo-induced homolytic cleavage of the Al-C bonds was investigated by means of stationary and transient UV/Vis spectroscopy, spin trapping experiments, as well as EPR and NMR spectroscopy. The experimental findings were supported by quantum chemical calculations. Reactivity studies enabled the utilization of the aluminum complexes as reactants in tin-free Giese-type reactions and carbonyl alkylations under ambient conditions, which both indicated radical-polar crossover behavior. A deeper understanding of the physical fundamentals and photochemical process was provided, furnishing in turn a new strategy to control the reactivity of bench-stable aluminum organometallics.
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Affiliation(s)
- Jonas O Wenzel
- Karlsruhe Institute of Technology (KIT), Institute of Inorganic Chemistry (AOC), Engesserstraße 15, 76131, Karlsruhe, Germany
| | - Johannes Werner
- Karlsruhe Institute of Technology (KIT), Institute of Physical Chemistry (IPC), Fritz-Haber-Weg 2, 76131, Karlsruhe, Germany
| | - Alexander Allgaier
- University of Stuttgart, Institute of Physical Chemistry, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Joris van Slageren
- University of Stuttgart, Institute of Physical Chemistry, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Israel Fernández
- Universidad Complutense de Madrid, Facultad de Ciencias Químicas, 28040, Madrid, Spain
| | - Andreas-Neil Unterreiner
- Karlsruhe Institute of Technology (KIT), Institute of Physical Chemistry (IPC), Fritz-Haber-Weg 2, 76131, Karlsruhe, Germany
| | - Frank Breher
- Karlsruhe Institute of Technology (KIT), Institute of Inorganic Chemistry (AOC), Engesserstraße 15, 76131, Karlsruhe, Germany
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12
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Tan HB, Liu YS, Zhou JY, Cao M, Lei T, Ren SY, Lin CQ, Yang YF, Hu ZL, Xu ZG, Tang DY, Chen ZZ, Qu XY. Tandem Vinylogous Aldol and Intramolecular [2 + 2] Cycloaddition toward Benzocyclobutenes by UV Light Photocatalysis. Org Lett 2024; 26:3304-3309. [PMID: 38587334 DOI: 10.1021/acs.orglett.4c00994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
A facile and efficient radical tandem vinylogous aldol and intramolecular [2 + 2] cycloaddition reaction for direct synthesis of cyclobutane-containing benzocyclobutenes (BCBs) under extremely mild conditions without using any photocatalysts is reported. This approach exhibited definite compatibility with functional groups and afforded new BCBs with excellent regioselectivity and high yields. Moreover, detailed mechanism studies were carried out both experimentally and theoretically. The readily accessible, low-cost, and ecofriendly nature of the developed strategy will endow it with attractive applications in organic and medicinal chemistry.
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Affiliation(s)
- Hong-Bo Tan
- National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Engineering Laboratory of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing Collaborative Innovation Center of Targeted and Innovative Therapeutics, College of Pharmacy & IATTI, Chongqing University of Arts and Sciences, Chongqing 402160, China
- Chongqing Academy of Chinese Materia Medica, Chongqing 400065, China
| | - Ying-Shan Liu
- National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Engineering Laboratory of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing Collaborative Innovation Center of Targeted and Innovative Therapeutics, College of Pharmacy & IATTI, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Jia-Ying Zhou
- National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Engineering Laboratory of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing Collaborative Innovation Center of Targeted and Innovative Therapeutics, College of Pharmacy & IATTI, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Man Cao
- National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Engineering Laboratory of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing Collaborative Innovation Center of Targeted and Innovative Therapeutics, College of Pharmacy & IATTI, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Tong Lei
- National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Engineering Laboratory of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing Collaborative Innovation Center of Targeted and Innovative Therapeutics, College of Pharmacy & IATTI, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Si-Ying Ren
- National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Engineering Laboratory of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing Collaborative Innovation Center of Targeted and Innovative Therapeutics, College of Pharmacy & IATTI, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Chang-Qiu Lin
- National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Engineering Laboratory of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing Collaborative Innovation Center of Targeted and Innovative Therapeutics, College of Pharmacy & IATTI, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Yi-Fan Yang
- National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Engineering Laboratory of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing Collaborative Innovation Center of Targeted and Innovative Therapeutics, College of Pharmacy & IATTI, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Zhang-Liang Hu
- National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Engineering Laboratory of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing Collaborative Innovation Center of Targeted and Innovative Therapeutics, College of Pharmacy & IATTI, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Zhi-Gang Xu
- National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Engineering Laboratory of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing Collaborative Innovation Center of Targeted and Innovative Therapeutics, College of Pharmacy & IATTI, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Dian-Yong Tang
- National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Engineering Laboratory of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing Collaborative Innovation Center of Targeted and Innovative Therapeutics, College of Pharmacy & IATTI, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Zhong-Zhu Chen
- National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Engineering Laboratory of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing Collaborative Innovation Center of Targeted and Innovative Therapeutics, College of Pharmacy & IATTI, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Xian-You Qu
- Chongqing Academy of Chinese Materia Medica, Chongqing 400065, China
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13
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Pramanik M, Guerzoni MG, Richards E, Melen RL. Recent Advances in Asymmetric Catalysis Using p-Block Elements. Angew Chem Int Ed Engl 2024; 63:e202316461. [PMID: 38038149 PMCID: PMC11497282 DOI: 10.1002/anie.202316461] [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: 10/31/2023] [Revised: 11/29/2023] [Accepted: 12/01/2023] [Indexed: 12/02/2023]
Abstract
The development of new methods for enantioselective reactions that generate stereogenic centres within molecules are a cornerstone of organic synthesis. Typically, metal catalysts bearing chiral ligands as well as chiral organocatalysts have been employed for the enantioselective synthesis of organic compounds. In this review, we highlight the recent advances in main group catalysis for enantioselective reactions using the p-block elements (boron, aluminium, phosphorus, bismuth) as a complementary and sustainable approach to generate chiral molecules. Several of these catalysts benefit in terms of high abundance, low toxicity, high selectivity, and excellent reactivity. This minireview summarises the utilisation of chiral p-block element catalysts for asymmetric reactions to generate value-added compounds.
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Affiliation(s)
- Milan Pramanik
- Cardiff Catalysis InstituteSchool of ChemistryCardiff UniversityTranslational Research HubMaindy RoadCathays, CardiffCF24 4HQCymru/WalesUK
| | - Michael G. Guerzoni
- Cardiff Catalysis InstituteSchool of ChemistryCardiff UniversityTranslational Research HubMaindy RoadCathays, CardiffCF24 4HQCymru/WalesUK
| | - Emma Richards
- Cardiff Catalysis InstituteSchool of ChemistryCardiff UniversityTranslational Research HubMaindy RoadCathays, CardiffCF24 4HQCymru/WalesUK
| | - Rebecca L. Melen
- Cardiff Catalysis InstituteSchool of ChemistryCardiff UniversityTranslational Research HubMaindy RoadCathays, CardiffCF24 4HQCymru/WalesUK
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14
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Zhao Z, Zhang T, Yue S, Wang P, Bao Y, Zhan S. Spin Polarization: A New Frontier in Efficient Photocatalysis for Environmental Purification and Energy Conversion. Chemphyschem 2024; 25:e202300726. [PMID: 38059760 DOI: 10.1002/cphc.202300726] [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: 10/03/2023] [Revised: 11/28/2023] [Accepted: 12/01/2023] [Indexed: 12/08/2023]
Abstract
As a promising strategy to improve photocatalytic efficiency, spin polarization has attracted enormous attention in recent years, which could be involved in various steps of photoreaction. The Pauli repulsion principle and the spin selection rule dictate that the behavior of two electrons in a spatial eigenstate is based on their spin states, and this fact opens up a new avenue for manipulating photocatalytic efficiency. In this review, recent advances in modulating the photocatalytic activity with spin polarization are systematically summarized. Fundamental insights into the influence of spin-polarization effects on photon absorption, carrier separation, and migration, and the behaviors of reaction-related substances from the photon uptake to reactant desorption are highlighted and discussed in detail, and various photocatalytic applications for environmental purification and energy conversion are presented. This review is expected to deliver a timely overview of the recent developments in spin-polarization-modulated photocatalysis for environmental purification and energy conversion in terms of their practical applications.
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Affiliation(s)
- Zhiyong Zhao
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, P. R. China
| | - Tao Zhang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, P. R. China
| | - Shuai Yue
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, P. R. China
| | - Pengfei Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, P. R. China
| | - Yueping Bao
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, P. R. China
| | - Sihui Zhan
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, P. R. China
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15
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Großkopf J, Bach T. Catalytic Photochemical Deracemization via Short-Lived Intermediates. Angew Chem Int Ed Engl 2023; 62:e202308241. [PMID: 37428113 DOI: 10.1002/anie.202308241] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/11/2023]
Abstract
Upon irradiation in the presence of a suitable chiral catalyst, racemic compound mixtures can be converted into enantiomerically pure compounds with the same constitution. The process is called photochemical deracemization and involves the formation of short-lived intermediates. By opening different reaction channels for the forward reaction to the intermediate and for the re-constitution of the chiral molecule, the entropically disfavored process becomes feasible. Since the discovery of the first photochemical deracemization in 2018, the field has been growing rapidly. This review comprehensively covers the research performed in the area and discusses current developments. It is subdivided according to the mode of action and the respective substrate classes. The focus of this review is on the scope of the individual reactions and on a discussion of the mechanistic details underlying the presented reaction.
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Affiliation(s)
- Johannes Großkopf
- School of Natural Sciences, Technische Universität München, Department Chemie and Catalysis Research Center (CRC), Lichtenbergstr. 4, 85747, Garching, Germany
| | - Thorsten Bach
- School of Natural Sciences, Technische Universität München, Department Chemie and Catalysis Research Center (CRC), Lichtenbergstr. 4, 85747, Garching, Germany
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16
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Großkopf J, Plaza M, Kutta RJ, Nuernberger P, Bach T. Creating a Defined Chirality in Amino Acids and Cyclic Dipeptides by Photochemical Deracemization. Angew Chem Int Ed Engl 2023; 62:e202313606. [PMID: 37793026 DOI: 10.1002/anie.202313606] [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: 09/13/2023] [Revised: 09/30/2023] [Accepted: 10/02/2023] [Indexed: 10/06/2023]
Abstract
2,5-Diketopiperazines are cyclic dipeptides displaying a wide range of applications. Their enantioselective preparation has now been found possible from the respective racemates by a photochemical deracemization (53 examples, 74 % to quantitative yield, 71-99 % ee). A chiral benzophenone catalyst in concert with irradiation at λ=366 nm enables to establish the configuration at the stereogenic carbon atom C6 at will. If other stereogenic centers are present in the diketopiperazines they remain unaffected and a stereochemical editing is possible at a single position. Consecutive reactions, including the conversion into N-aryl or N-alkyl amino acids or the reduction to piperazines, occur without compromising the newly created stereogenic center. Transient absorption spectroscopy revealed that the benzophenone catalyst processes one enantiomer of the 2,5-diketopiperazines preferentially and enables a reversible hydrogen atom transfer that is responsible for the deracemization process. The remarkably long lifetime of the protonated ketyl radical implies a yet unprecedented mode of action.
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Affiliation(s)
- Johannes Großkopf
- Department Chemie and Catalysis Research Center (CRC), School of Natural Sciences, Technische Universität München, D-85747, Garching, Germany
| | - Manuel Plaza
- Department Chemie and Catalysis Research Center (CRC), School of Natural Sciences, Technische Universität München, D-85747, Garching, Germany
| | - Roger Jan Kutta
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstr. 31, D-93053, Regensburg, Germany
| | - Patrick Nuernberger
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstr. 31, D-93053, Regensburg, Germany
| | - Thorsten Bach
- Department Chemie and Catalysis Research Center (CRC), School of Natural Sciences, Technische Universität München, D-85747, Garching, Germany
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17
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Kim SF, Sarpong R. Interconverting mirror-image molecules. Science 2023; 382:373-374. [PMID: 37883536 DOI: 10.1126/science.adk7116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
A light-driven multitasking catalyst enhances chirality in molecular mixtures.
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Affiliation(s)
- Sojung F Kim
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Richmond Sarpong
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
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