51
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Stegbauer S, Jandl C, Bach T. Enantioselective Lewis Acid Catalyzed ortho Photocycloaddition of Olefins to Phenanthrene-9-carboxaldehydes. Angew Chem Int Ed Engl 2018; 57:14593-14596. [PMID: 30225921 PMCID: PMC6220838 DOI: 10.1002/anie.201808919] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/07/2018] [Indexed: 11/21/2022]
Abstract
Visible-light irradiation (λ=457 nm) enabled the enantioselective ortho photocycloaddition of olefins to phenanthrene-9-carboxaldehydes (15 examples, 46-93 % yield, 82-98 % ee). A chiral oxazaborolidine Lewis acid (20 mol %) was employed as the catalyst. It operates by coordination to the aldehyde inducing a bathochromic absorption shift beyond the nπ* absorption of the uncomplexed aldehyde. At long wavelengths the Lewis acid complex is exclusively excited; within the complex, one enantiotopic face of the aromatic aldehyde is efficiently shielded. Lewis acid coordination also alters the type selectivity and the simple diastereoselectivity of the photocycloaddition.
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Affiliation(s)
- Simone Stegbauer
- Department Chemie and Catalysis Research Center (CRC)Technische Universität MünchenLichtenbergstr. 485747GarchingGermany
| | - Christian Jandl
- Department Chemie and Catalysis Research Center (CRC)Technische Universität MünchenLichtenbergstr. 485747GarchingGermany
| | - Thorsten Bach
- Department Chemie and Catalysis Research Center (CRC)Technische Universität MünchenLichtenbergstr. 485747GarchingGermany
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52
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Stegbauer S, Jandl C, Bach T. Enantioselektive Lewis-Säure-katalysierte ortho
-Photocycloaddition von Phenanthren-9-carbaldehyden. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201808919] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Simone Stegbauer
- Department Chemie und Catalysis Research Center (CRC); Technische Universität München; Lichtenbergstr. 4 85747 Garching Deutschland
| | - Christian Jandl
- 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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53
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Kramm F, Teske J, Ullwer F, Frey W, Plietker B. Anellierte Cyclobutane durch Fe‐katalysierte Cycloisomerisierung von Eninacetaten. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201806693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Frederik Kramm
- Institut für Organische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
| | - Johannes Teske
- Institut für Organische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
| | - Franziska Ullwer
- Institut für Organische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
| | - Wolfgang Frey
- Institut für Organische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
| | - Bernd Plietker
- Institut für Organische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
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54
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Kramm F, Teske J, Ullwer F, Frey W, Plietker B. Annelated Cyclobutanes by Fe‐Catalyzed Cycloisomerization of Enyne Acetates. Angew Chem Int Ed Engl 2018; 57:13335-13338. [DOI: 10.1002/anie.201806693] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Frederik Kramm
- Institut für Organische ChemieUniversität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Johannes Teske
- Institut für Organische ChemieUniversität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Franziska Ullwer
- Institut für Organische ChemieUniversität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Wolfgang Frey
- Institut für Organische ChemieUniversität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Bernd Plietker
- Institut für Organische ChemieUniversität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
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55
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Ramanjaneyulu BT, Vishwakarma NK, Vidyacharan S, Adiyala PR, Kim DP. Towards Versatile Continuous-Flow Chemistry and Process Technology Via New Conceptual Microreactor Systems. B KOREAN CHEM SOC 2018. [DOI: 10.1002/bkcs.11467] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Bandaru T. Ramanjaneyulu
- Department of Chemical Engineering; Pohang University of Science and Technology (POSTECH); Pohang 37673 Korea
| | - Niraj K. Vishwakarma
- Department of Chemical Engineering; Pohang University of Science and Technology (POSTECH); Pohang 37673 Korea
| | - Shinde Vidyacharan
- Department of Chemical Engineering; Pohang University of Science and Technology (POSTECH); Pohang 37673 Korea
| | - Praveen Reddy Adiyala
- Department of Chemical Engineering; Pohang University of Science and Technology (POSTECH); Pohang 37673 Korea
| | - Dong-Pyo Kim
- Department of Chemical Engineering; Pohang University of Science and Technology (POSTECH); Pohang 37673 Korea
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56
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Hao J, Xu X, Fei H, Li L, Yan B. Functionalization of Metal-Organic Frameworks for Photoactive Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1705634. [PMID: 29388716 DOI: 10.1002/adma.201705634] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 10/19/2017] [Indexed: 05/05/2023]
Abstract
Metal-organic frameworks (MOFs) are intriguing platforms with multiple functionalities. Additional functionalization of MOFs generates novel materials for various applications. Here, three main topics are examined regarding the functionalization of MOFs for use as photoactive materials. The first is chemical approaches for postsynthetic modification of the metal clusters and organic linkers in MOFs; that is, sites on pore surfaces and chemical trapping of photoactive moieties within the pores, which create materials with chemical functionalities for water splitting and CO2 reduction by light. The second topic focuses on the functionalization of MOFs for photochemical response and the versatile applications of such materials. State-of-the-art research on functionalizing MOFs through photochemical reactions on the pore surface and within the pores as guests is also summarized. The third topic introduces the functionalization of MOFs for photofunctional materials, including photoluminescent tuning and integration, photoluminescent LED devices and barcodes, and photophysical applications for chemical sensing. Finally, conclusions and perspectives on the fields are given.
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Affiliation(s)
- Jina Hao
- School of Chemical Science and Engineering, Tongji University, Siping Road 1239, Shanghai, 200092, China
| | - Xiaoyu Xu
- School of Chemical Science and Engineering, Tongji University, Siping Road 1239, Shanghai, 200092, China
| | - Honghan Fei
- School of Chemical Science and Engineering, Tongji University, Siping Road 1239, Shanghai, 200092, China
| | - Liangchun Li
- School of Chemical Science and Engineering, Tongji University, Siping Road 1239, Shanghai, 200092, China
| | - Bing Yan
- School of Chemical Science and Engineering, Tongji University, Siping Road 1239, Shanghai, 200092, China
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57
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Zech A, Bach T. Photochemical Reaction Cascade from O-Pent-4-enyl-Substituted Salicylates to Complex Multifunctional Scaffolds. J Org Chem 2018; 83:3069-3077. [PMID: 29478316 DOI: 10.1021/acs.joc.8b00238] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The arene ring of the title compounds is cleaved by a reaction cascade which is initiated by an intramolecular ortho photocycloaddition reaction. Tricyclic products were obtained in a highly regio- and diastereoselective fashion via a cyclooctatriene intermediate. The facial diastereoselectivity exerted by a stereogenic center in the tether is moderate to good (dr = 65/35 to 82/18). Yields were acceptable (44-87%) except for a single substrate which had a geminal dimethyl substitution in the tether and which gave the respective product in only 14% yield. The reaction is stereoconvergent with regard to the olefin configuration ( E or Z) in agreement with a triplet mechanism of the ortho photocycloaddition step.
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Affiliation(s)
- Andreas Zech
- 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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58
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Lefebvre C, Michelin C, Martzel T, Djou’ou Mvondo V, Bulach V, Abe M, Hoffmann N. Photochemically Induced Intramolecular Radical Cyclization Reactions with Imines. J Org Chem 2018; 83:1867-1875. [DOI: 10.1021/acs.joc.7b02810] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Corentin Lefebvre
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Clément Michelin
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Thomas Martzel
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Vaneck Djou’ou Mvondo
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Véronique Bulach
- Laboratoire
de Tectonique Moléculaire (UMR 7140), Institut Le Bel, Université de Strasbourg, 4, rue Blaise Pascal, 67000 Strasbourg, France
| | - Manabu Abe
- Department
of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Hiroshima Research
Center for Photo-Drug-Delivery Systems (Hi-P-DDS), 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Norbert Hoffmann
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
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59
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Cheng B, Zu B, Li Y, Zhai S, Xu W, Li Y, Zhai H. Unified Strategy to Access 6H
-Benzofuro[2,3-b
]indoles and 5,6-Dihydroindolo[2,3-b
]indoles via UV Light-Mediated Diradical Cyclization. Adv Synth Catal 2017. [DOI: 10.1002/adsc.201701270] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Bin Cheng
- State Key Laboratory of Applied Organic Chemistry; College of Chemistry and Chemical Engineering; Lanzhou University; Lanzhou 730000 People's Republic of China
| | - Bing Zu
- State Key Laboratory of Applied Organic Chemistry; College of Chemistry and Chemical Engineering; Lanzhou University; Lanzhou 730000 People's Republic of China
| | - Yuntong Li
- State Key Laboratory of Applied Organic Chemistry; College of Chemistry and Chemical Engineering; Lanzhou University; Lanzhou 730000 People's Republic of China
| | - Shengxian Zhai
- State Key Laboratory of Applied Organic Chemistry; College of Chemistry and Chemical Engineering; Lanzhou University; Lanzhou 730000 People's Republic of China
| | - Wei Xu
- State Key Laboratory of Applied Organic Chemistry; College of Chemistry and Chemical Engineering; Lanzhou University; Lanzhou 730000 People's Republic of China
| | - Yun Li
- State Key Laboratory of Applied Organic Chemistry; College of Chemistry and Chemical Engineering; Lanzhou University; Lanzhou 730000 People's Republic of China
| | - Hongbin Zhai
- State Key Laboratory of Applied Organic Chemistry; College of Chemistry and Chemical Engineering; Lanzhou University; Lanzhou 730000 People's Republic of China
- Key Laboratory of Chemical Genomics; School of Chemical Biology and Biotechnology; Shenzhen Graduate School of Peking University; Shenzhen 518055 People's Republic of China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); Tianjin 300071 People's Republic of China
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60
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Lazzaroni S, Ravelli D, Protti S, Fagnoni M, Albini A. Photochemical synthesis: Using light to build C–C bonds under mild conditions. CR CHIM 2017. [DOI: 10.1016/j.crci.2015.11.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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61
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Liu Q, Wang J, Li D, Yang C, Xia W. Photoinduced Intermolecular [4+2] Cycloaddition Reaction for Construction of Benzobicyclo[2.2.2]octane Skeletons. J Org Chem 2017; 82:1389-1402. [DOI: 10.1021/acs.joc.6b02547] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Qiang Liu
- School of Chemistry and Chemical
Engineering, State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150080, China
| | - Junlei Wang
- School of Chemistry and Chemical
Engineering, State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150080, China
| | - Dazhi Li
- School of Chemistry and Chemical
Engineering, State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150080, China
| | - Chao Yang
- School of Chemistry and Chemical
Engineering, State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150080, China
| | - Wujiong Xia
- School of Chemistry and Chemical
Engineering, State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150080, China
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62
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Reinvestigation of the photoreaction of 1,4-bis(2,4,6-triphenylpyridinio)benzene: Synthesis of a diazonia derivative of hexabenzoperylene by multiple photocyclization. J Photochem Photobiol A Chem 2016. [DOI: 10.1016/j.jphotochem.2016.06.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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63
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Ravelli D, Protti S, Fagnoni M. Decatungstate Anion for Photocatalyzed "Window Ledge" Reactions. Acc Chem Res 2016; 49:2232-2242. [PMID: 27648722 DOI: 10.1021/acs.accounts.6b00339] [Citation(s) in RCA: 189] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The majority of organic reactions are commonly carried out inside a lab, under a fume hood. A particular case is that of photochemical reactions, a field where the pioneering experiments by Giacomo Ciamician demonstrated more than one century ago that different processes can be carried out outdoors, for example, on the balcony of his own department, upon exposure of the reacting mixtures to sunlight. The main problem related to this chemistry of the "window ledge" is that most organic compounds are colorless and their absorption in the solar light region is in most cases negligible. Recently, the impressive development in the use of visible light absorbing photocatalysts (e.g., RuII or IrIII complexes, as well as organic dyes) made light-induced processes convenient even for non-photochemistry practitioners. It is thus possible to easily perform the reactions by simply placing the reaction vessel in a sunny place outside the lab. However, most of these processes are based on single electron transfer (SET) reactions (photoredox catalysis). Other photocatalysts able to activate substrates via alternative paths, such as hydrogen atom transfer (HAT), are emerging. In the last years, we were deeply involved in the use of the decatungstate anion ([W10O32]4-, a polyoxometalate) in synthesis. Indeed, such a versatile species is able to promote the photocatalytic C-H activation of organic compounds via either SET or HAT reactions. Interestingly, though the absorption spectrum of [W10O32]4- does not extend into the visible region, it shows an overlap with solar light emission. In this Account, we provide an overview on the application of decatungstate salts as photocatalysts in window ledge chemistry. We initially discuss the nature of the photogenerated species involved in the mechanism of action of the anion, also supported by theoretical simulations. The first-formed excited state of the decatungstate anion decays rapidly to the active species, a dark state tagged wO, featuring the presence of electron-deficient oxygen centers. Next, we describe the main applications of decatungstate chemistry. A significant part of this Account is devoted to photocatalyzed synthesis (C-X bond formation, with X = C, N, O, and oxidations) carried out by adopting sunlight (or simulated solar light). This synthetic approach is versatile, and most of the reactions involved C-H activation in cycloalkanes, alkylaromatics, amides, ethers (1,4-dioxane, oxetane, benzodioxole, and THF), aldehydes, nitriles, and cyclopentanones, and the ensuing addition of the resulting radicals onto electron-deficient olefins. Finally, the increasing role of the decatungstate anion in water depollution and polymerization is briefly discussed.
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Affiliation(s)
- Davide Ravelli
- PhotoGreen
Lab, Department
of Chemistry, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Stefano Protti
- PhotoGreen
Lab, Department
of Chemistry, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Maurizio Fagnoni
- PhotoGreen
Lab, Department
of Chemistry, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
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64
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Kärkäs M, Porco JA, Stephenson CRJ. Photochemical Approaches to Complex Chemotypes: Applications in Natural Product Synthesis. Chem Rev 2016; 116:9683-747. [PMID: 27120289 PMCID: PMC5025835 DOI: 10.1021/acs.chemrev.5b00760] [Citation(s) in RCA: 666] [Impact Index Per Article: 83.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Indexed: 01/29/2023]
Abstract
The use of photochemical transformations is a powerful strategy that allows for the formation of a high degree of molecular complexity from relatively simple building blocks in a single step. A central feature of all light-promoted transformations is the involvement of electronically excited states, generated upon absorption of photons. This produces transient reactive intermediates and significantly alters the reactivity of a chemical compound. The input of energy provided by light thus offers a means to produce strained and unique target compounds that cannot be assembled using thermal protocols. This review aims at highlighting photochemical transformations as a tool for rapidly accessing structurally and stereochemically diverse scaffolds. Synthetic designs based on photochemical transformations have the potential to afford complex polycyclic carbon skeletons with impressive efficiency, which are of high value in total synthesis.
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Affiliation(s)
- Markus
D. Kärkäs
- Department
of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - John A. Porco
- Department
of Chemistry, Center for Molecular Discovery (BU-CMD), Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Corey R. J. Stephenson
- Department
of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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65
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Oelgemöller M, Hoffmann N. Studies in organic and physical photochemistry - an interdisciplinary approach. Org Biomol Chem 2016; 14:7392-442. [PMID: 27381273 DOI: 10.1039/c6ob00842a] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Traditionally, organic photochemistry when applied to synthesis strongly interacts with physical chemistry. The aim of this review is to illustrate this very fruitful interdisciplinary approach and cooperation. A profound understanding of the photochemical reactivity and reaction mechanisms is particularly helpful for optimization and application of these reactions. Some typical reactions and particular aspects are reported such as the Norrish-Type II reaction and the Yang cyclization and related transformations, the [2 + 2] photocycloadditions, particularly the Paternò-Büchi reaction, photochemical electron transfer induced transformations, different kinds of catalytic reactions such as photoredox catalysis for organic synthesis and photooxygenation are discussed. Particular aspects such as the structure and reactivity of aryl cations, photochemical reactions in the crystalline state, chiral memory, different mechanisms of hydrogen transfer in photochemical reactions or fundamental aspects of stereoselectivity are discussed. Photochemical reactions are also investigated in the context of chemical engineering. Particularly, continuous flow reactors are of interest. Novel reactor systems are developed and modeling of photochemical transformations and different reactors play a key role in such studies. This research domain builds a bridge between fundamental studies of organic photochemical reactions and their industrial application.
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Affiliation(s)
- Michael Oelgemöller
- James Cook University, College of Science and Engineering, Townsville, QLD 4811, Australia.
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66
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Kim S, Park G, Cho EJ, You Y. Coreactant Strategy for the Photoredox Catalytic Generation of Trifluoromethyl Radicals under Low-Energy Photoirradiation. J Org Chem 2016; 81:7072-9. [DOI: 10.1021/acs.joc.6b00966] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Eun Jin Cho
- Department
of Chemistry, Chung-Ang University, Seoul 06974, Republic of Korea
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67
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Kuznetsov DM, Mukhina OA, Kutateladze AG. Photoassisted Synthesis of Complex Molecular Architectures: Dearomatization of Benzenoid Arenes with Aza-o-xylylenes via an Unprecedented [2+4] Reaction Topology. Angew Chem Int Ed Engl 2016; 55:6988-91. [PMID: 27097759 PMCID: PMC4943229 DOI: 10.1002/anie.201602288] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Indexed: 11/06/2022]
Abstract
A new method was developed for the photoinduced dearomatization of arenes through an intramolecular cycloaddition with aza-o-xylylenes generated by excited-state intramolecular proton transfer (ESIPT) in the readily available photoprecursors. The [2+4] topology of this cycloaddition is unprecedented for photo-dearomatizations of benzenoid aromatic carbocycles. It provides rapid access to novel heterocycles, cyclohexadieno-oxazolidino-quinolinols, as valuable synthons for a broad range of post-photochemical transformations.
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Affiliation(s)
- Dmitry M Kuznetsov
- Department of Chemistry and Biochemistry, University of Denver, 2190 E. Iliff Ave., Denver, CO, 80208, USA
| | - Olga A Mukhina
- Department of Chemistry and Biochemistry, University of Denver, 2190 E. Iliff Ave., Denver, CO, 80208, USA
| | - Andrei G Kutateladze
- Department of Chemistry and Biochemistry, University of Denver, 2190 E. Iliff Ave., Denver, CO, 80208, USA.
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68
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Oelgemöller M. Solar Photochemical Synthesis: From the Beginnings of Organic Photochemistry to the Solar Manufacturing of Commodity Chemicals. Chem Rev 2016; 116:9664-82. [PMID: 27181285 DOI: 10.1021/acs.chemrev.5b00720] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Natural sunlight offers a cost-efficient and sustainable energy source for photochemical reactions. In contrast to the lengthy and small-scale "flask in the sun" procedures of the past, modern solar concentrator systems nowadays significantly shorten reaction times and enable technical-scale operations. After a brief historical introduction, this review presents the most important solar reactor types and their successful application in preparative solar syntheses. The examples demonstrate that solar manufacturing of fine chemicals is technically feasible and environmentally sustainable. After over 100 years, Ciamician's prophetic vision of "the photochemistry of the future" as a clean and green manufacturing methodology has yet to be realized. At the same time, his warning "for nature is not in a hurry but mankind is" is still valid today. It is hoped that this review will lead to a renewed interest in this truly enlightening technology, that it will stimulate photochemists and photochemical engineers to "go back to the roots onto the roofs" and that it will ultimately result in industrial applications in the foreseeable future.
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Affiliation(s)
- Michael Oelgemöller
- College of Science and Engineering, James Cook University , Townsville, Queensland 4811, Australia
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69
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Kuznetsov DM, Mukhina OA, Kutateladze AG. Photoassisted Synthesis of Complex Molecular Architectures: Dearomatization of Benzenoid Arenes with Aza-o-xylylenes via an Unprecedented [2+4] Reaction Topology. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201602288] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Dmitry M. Kuznetsov
- Department of Chemistry and Biochemistry; University of Denver; 2190 E. Iliff Ave. Denver CO 80208 USA
| | - Olga A. Mukhina
- Department of Chemistry and Biochemistry; University of Denver; 2190 E. Iliff Ave. Denver CO 80208 USA
| | - Andrei G. Kutateladze
- Department of Chemistry and Biochemistry; University of Denver; 2190 E. Iliff Ave. Denver CO 80208 USA
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70
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71
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Cambié D, Bottecchia C, Straathof NJW, Hessel V, Noël T. Applications of Continuous-Flow Photochemistry in Organic Synthesis, Material Science, and Water Treatment. Chem Rev 2016; 116:10276-341. [PMID: 26935706 DOI: 10.1021/acs.chemrev.5b00707] [Citation(s) in RCA: 882] [Impact Index Per Article: 110.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Continuous-flow photochemistry in microreactors receives a lot of attention from researchers in academia and industry as this technology provides reduced reaction times, higher selectivities, straightforward scalability, and the possibility to safely use hazardous intermediates and gaseous reactants. In this review, an up-to-date overview is given of photochemical transformations in continuous-flow reactors, including applications in organic synthesis, material science, and water treatment. In addition, the advantages of continuous-flow photochemistry are pointed out and a thorough comparison with batch processing is presented.
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Affiliation(s)
- Dario Cambié
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry and Process Technology, Eindhoven University of Technology , Den Dolech 2, 5600 MB Eindhoven, The Netherlands
| | - Cecilia Bottecchia
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry and Process Technology, Eindhoven University of Technology , Den Dolech 2, 5600 MB Eindhoven, The Netherlands
| | - Natan J W Straathof
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry and Process Technology, Eindhoven University of Technology , Den Dolech 2, 5600 MB Eindhoven, The Netherlands
| | - Volker Hessel
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry and Process Technology, Eindhoven University of Technology , Den Dolech 2, 5600 MB Eindhoven, The Netherlands
| | - Timothy Noël
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry and Process Technology, Eindhoven University of Technology , Den Dolech 2, 5600 MB Eindhoven, The Netherlands.,Department of Organic Chemistry, Ghent University , Krijgslaan 281 (S4), 9000 Ghent, Belgium
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72
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Rehm TH, Gros S, Löb P, Renken A. Photonic contacting of gas–liquid phases in a falling film microreactor for continuous-flow photochemical catalysis with visible light. REACT CHEM ENG 2016. [DOI: 10.1039/c6re00169f] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A microstructured falling film reactor was applied to the dye-sensitized photochemical conversion of 1,5-dihydroxynaphthalene to juglone for reactor and process evaluation.
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Affiliation(s)
| | - Sylvain Gros
- Fraunhofer ICT-IMM
- 55129 Mainz
- Germany
- École Polytechnique Fédérale de Lausanne
- EPFL-ISIC
| | | | - Albert Renken
- École Polytechnique Fédérale de Lausanne
- EPFL-ISIC
- 1015 Lausanne
- Switzerland
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73
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Josland S, Mumtaz S, Oelgemöller M. Photodecarboxylations in an Advanced Meso-Scale Continuous-Flow Photoreactor. Chem Eng Technol 2015. [DOI: 10.1002/ceat.201500285] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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74
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Abstract
AbstractRadicals are easily generated via hydrogen transfer form secondary alcohols or tertiary amines using photochemical sensitization with ketones. They can subsequently add to the electron deficient double bond of furanones. The addition of the alcohols is particularly efficient. Therefore, this reaction was used to characterize and to compare the efficiency of different photochemical continuous flow microreactors. A range of micro-structured reactors were tested and their performances evaluated. The enclosed microchip enabled high space-time-yields but its microscopic dimensions limited its productivity. In contrast, the open microcapillary model showed a greater potential for scale-up and reactor optimization. A 10-microcapillary reactor was therefore constructed and utilized for typical R&D applications. Compared to the corresponding batch processes, the microreactor systems gave faster conversions, improved product qualities and higher yields. Similar reactions have also been carried out with electronically excited furanones and other α,β-unsaturated ketones. In this case, hydrogen is transferred directly to the excited olefin. This reaction part may occur either in one step, i.e., electron and proton are transferred simultaneously, or it may occur in two steps, i.e., the electron is transferred first and the proton follows. In the first case, a C–C bond is formed in the α position of the α,β-unsaturated carbonyl compound and in the second case this bond is formed in the β position. For the first reaction, the influence of stereochemical elements of the substrate on the regioselectivity of the hydrogen abstraction on the side chain has been studied.
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Affiliation(s)
- Michael Oelgemöller
- 1College of Science, Technology and Engineering, James Cook University, Townsville, QLD 4811, Australia
| | - Norbert Hoffmann
- 2CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
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75
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Choi WJ, Choi S, Ohkubo K, Fukuzumi S, Cho EJ, You Y. Mechanisms and applications of cyclometalated Pt(ii) complexes in photoredox catalytic trifluoromethylation. Chem Sci 2015; 6:1454-1464. [PMID: 29560234 PMCID: PMC5811153 DOI: 10.1039/c4sc02537g] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 11/21/2014] [Indexed: 11/24/2022] Open
Abstract
The incorporation of a trifluoromethyl group into an existing scaffold can provide an effective strategy for designing new drugs and agrochemicals. Among the numerous approaches to trifluoromethylation, radical trifluoromethylation mediated by visible light-driven photoredox catalysis has gathered significant interest as it offers unique opportunities for circumventing the drawbacks encountered in conventional methods. A limited understanding of the mechanism and molecular parameters that control the catalytic actions has hampered the full utilization of photoredox catalysis reactions. To address this challenge, we evaluated and investigated the photoredox catalytic trifluoromethylation reaction using a series of cyclometalated Pt(ii) complexes with systematically varied ligand structures. The Pt(ii) complexes were capable of catalyzing the trifluoromethylation of non-prefunctionalized alkenes and heteroarenes in the presence of CF3I under visible light irradiation. The high excited-state redox potentials of the complexes permitted oxidative quenching during the cycle, whereas reductive quenching was forbidden. Spectroscopic measurements, including time-resolved photoluminescence and laser flash photolysis, were performed to identify the catalytic intermediates and directly monitor their conversions. The mechanistic studies provide compelling evidence that the catalytic cycle selects the oxidative quenching pathway. We also found that electron transfer during each step of the cycle strictly adhered to the Marcus normal region behaviors. The results are fully supported by additional experiments, including photoinduced ESR spectroscopy, spectroelectrochemical measurements, and quantum chemical calculations based on time-dependent density functional theory. Finally, quantum yields exceeding 100% strongly suggest that radical propagation significantly contributes to the catalytic trifluoromethylation reaction. These findings establish molecular strategies for designing trifluoromethyl sources and catalysts in an effort to enhance catalysis performance.
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Affiliation(s)
- Won Joon Choi
- Department of Advanced Materials Engineering for Information and Electronics , Kyung Hee University , Yongin , Gyeonggi-do 446-701 , Korea .
| | - Sungkyu Choi
- Department of Applied Chemistry & Department of Bionanotechnology , Hanyang University , Ansan , Gyeonggi-do 426-791 , Korea .
| | - Kei Ohkubo
- Department of Material and Life Science , Graduate School of Engineering , Osaka University , ALCA , Japan Science and Technology Agency (JST) , Suita , Osaka 565-0871 , Japan .
| | - Shunichi Fukuzumi
- Department of Material and Life Science , Graduate School of Engineering , Osaka University , ALCA , Japan Science and Technology Agency (JST) , Suita , Osaka 565-0871 , Japan .
| | - Eun Jin Cho
- Department of Applied Chemistry & Department of Bionanotechnology , Hanyang University , Ansan , Gyeonggi-do 426-791 , Korea .
| | - Youngmin You
- Department of Advanced Materials Engineering for Information and Electronics , Kyung Hee University , Yongin , Gyeonggi-do 446-701 , Korea .
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76
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Barata-Vallejo S, Bonesi SM, Postigo A. Photocatalytic fluoroalkylation reactions of organic compounds. Org Biomol Chem 2015; 13:11153-83. [DOI: 10.1039/c5ob01486g] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Photocatalytic methods for fluoroalkyl-radical generation provide more convenient alternatives to the classical perfluoroalkyl-radical (Rf) production through chemical initiators, such as azo or peroxide compounds or the employment of transition metals through a thermal electron transfer (ET) initiation process.
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Affiliation(s)
- Sebastián Barata-Vallejo
- Departamento de Química Orgánica
- Facultad de Farmacia y Bioquímica
- Universidad de Buenos Aires
- Buenos Aires
- Argentina
| | - Sergio M. Bonesi
- Departamento de Química Orgánica
- CIHIDECAR-CONICET
- Pabellón II
- 3er piso
- Ciudad Universitaria
| | - Al Postigo
- Departamento de Química Orgánica
- Facultad de Farmacia y Bioquímica
- Universidad de Buenos Aires
- Buenos Aires
- Argentina
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77
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Crespi S, Ravelli D, Protti S, Albini A, Fagnoni M. Competing pathways in the photogeneration of didehydrotoluenes from (Trimethylsilylmethyl)aryl sulfonates and phosphates. Chemistry 2014; 20:17572-8. [PMID: 25358804 DOI: 10.1002/chem.201404787] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Indexed: 11/11/2022]
Abstract
The scope of the photochemical generation of α,n-didehydrotoluene diradicals from aryl sulfonates and phosphates and their chemistry are explored. The thermally inaccessible α,2- and α,4- intermediates are efficiently obtained by irradiation of ortho- and para-(trimethylsilylmethyl)phenyl triflates through heterolytic splitting of the ester anion from the substrate in the triplet state. Triplet phenyl cations are formed and the loss of trimethylsilyl cation from them affords the desired diradicals ((3) Me3 SiCH2 C6 H4 -OZ→(3) Me3 SiCH2 C6 H4 (+) →(⋅) CH2 C6 H4 (⋅)). Triplet sensitization is required, for which acetone is used throughout. Direct irradiation leads, on the contrary, to photo-Fries fragmentation ((1) Me3 SiCH2 C6 H4 O-Z→Me3 SiCH2 C6 H4 O(⋅) +Z(⋅)). With mesylates, where ester cleavage is less convenient, a further competition from the triplet is direct desilylation. Didehydrotoluenes are also obtained from the corresponding phosphates, although with poor efficiency.
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Affiliation(s)
- Stefano Crespi
- PhotoGreen Lab, Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100 Pavia (Italy)
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78
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Affiliation(s)
- Norbert Hoffmann
- CNRS, Université de Reims Champagne-Ardenne; ICMR, Equipe de Photochimie; UFR Sciences, B.P. 1039 51687 Reims France
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79
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Sagud I, Božić S, Marinić Z, Sindler-Kulyk M. Photochemical approach to functionalized benzobicyclo[3.2.1]octene structures via fused oxazoline derivatives from 4- and 5-(o-vinylstyryl)oxazoles. Beilstein J Org Chem 2014; 10:2222-9. [PMID: 25246981 PMCID: PMC4168845 DOI: 10.3762/bjoc.10.230] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/04/2014] [Indexed: 12/11/2022] Open
Abstract
Novel cis/trans-4- and cis/trans-5-(2-vinylstyryl)oxazoles have been synthesized by Wittig reactions from the diphosphonium salt of α,α’-o-xylene dibromide, formaldehyde and 4- and 5-oxazolecarbaldehydes, respectively. In contrast, trans-5-(2-vinylstyryl)oxazole has been synthesized by the van Leusen reaction from trans-3-(2-vinylphenyl)acrylaldehyde which is prepared from o-vinylbenzaldehyde and (formylmethylene)triphenylphosphorane. The 4- and 5-(2-vinylstyryl)oxazoles afford, by photochemical intramolecular cycloaddition, diverse fused oxazoline-benzobicyclo[3.2.1]octadienes, which are identified and characterized by spectroscopic methods. The photoproducts formed are relatively unstable and spontaneously or on silica gel undergo oxazoline ring opening followed by formation of formiato- or formamido-benzobicyclo[3.2.1]octenone derivatives. On irradiation of 4-(2-vinylstyryl)oxazole small quantities of electrocyclization product, 4-(1,2-dihydronaphthalen-2-yl)oxazole, are isolated and spectroscopically characterized.
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Affiliation(s)
- Ivana Sagud
- Department of Organic Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, 10000 Zagreb, Croatia
| | - Simona Božić
- Department of Organic Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, 10000 Zagreb, Croatia
| | - Zeljko Marinić
- NMR Center, Rudjer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Marija Sindler-Kulyk
- Department of Organic Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, 10000 Zagreb, Croatia
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80
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Su Y, Straathof NJW, Hessel V, Noël T. Photochemical transformations accelerated in continuous-flow reactors: basic concepts and applications. Chemistry 2014; 20:10562-89. [PMID: 25056280 DOI: 10.1002/chem.201400283] [Citation(s) in RCA: 364] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Indexed: 11/10/2022]
Abstract
Continuous-flow photochemistry is used increasingly by researchers in academia and industry to facilitate photochemical processes and their subsequent scale-up. However, without detailed knowledge concerning the engineering aspects of photochemistry, it can be quite challenging to develop a suitable photochemical microreactor for a given reaction. In this review, we provide an up-to-date overview of both technological and chemical aspects associated with photochemical processes in microreactors. Important design considerations, such as light sources, material selection, and solvent constraints are discussed. In addition, a detailed description of photon and mass-transfer phenomena in microreactors is made and fundamental principles are deduced for making a judicious choice for a suitable photomicroreactor. The advantages of microreactor technology for photochemistry are described for UV and visible-light driven photochemical processes and are compared with their batch counterparts. In addition, different scale-up strategies and limitations of continuous-flow microreactors are discussed.
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Affiliation(s)
- Yuanhai Su
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry and Process Technology, Eindhoven University of Technology, Den Dolech 2 (STW 1.48), 5600 MB Eindhoven (The Netherlands) http://www.tue.nl/staff/T.Noel
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81
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Aromatics to bis-triquinane: a tandem oxidative dearomatization of bis-phenol, cycloaddition, photorearrangement and a rapid entry into carbocyclic framework of Xeromphalinone E. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.05.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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82
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Hoffmann N. Photochemical reactions applied to the synthesis of helicenes and helicene-like compounds. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2014. [DOI: 10.1016/j.jphotochemrev.2013.11.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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83
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Martin V, Goodell JR, Ingham OJ, Porco JA, Beeler AB. Multidimensional reaction screening for photochemical transformations as a tool for discovering new chemotypes. J Org Chem 2014; 79:3838-46. [PMID: 24697145 PMCID: PMC4017617 DOI: 10.1021/jo500190b] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Indexed: 01/11/2023]
Abstract
We have developed an automated photochemical microfluidics platform that integrates a 1 kW high-pressure Hg vapor lamp and allows for analytical pulse flow or preparative continuous flow reactions. Herein, we will discuss the use of this platform toward the discovery of new chemotypes through multidimensional reaction screening. We will highlight the ability to discretely control wavelengths with optical filters, allowing for control of reaction outcomes.
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Affiliation(s)
- Véronique
I. Martin
- Department
of Chemistry and
Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - John R. Goodell
- Department
of Chemistry and
Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Oscar J. Ingham
- Department
of Chemistry and
Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - John A. Porco
- Department
of Chemistry and
Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Aaron B. Beeler
- Department
of Chemistry and
Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
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84
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Zhang N, Samanta SR, Rosen BM, Percec V. Single Electron Transfer in Radical Ion and Radical-Mediated Organic, Materials and Polymer Synthesis. Chem Rev 2014; 114:5848-958. [DOI: 10.1021/cr400689s] [Citation(s) in RCA: 320] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Na Zhang
- Roy & Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Shampa R. Samanta
- Roy & Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Brad M. Rosen
- DuPont Titanium Technologies, Chestnut Run Plaza, Wilmington, Delaware 19805, United States
| | - Virgil Percec
- Roy & Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
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85
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Kee CW, Chan KM, Wong MW, Tan CH. Selective Bromination of sp3CH Bonds by Organophotoredox Catalysis. ASIAN J ORG CHEM 2013. [DOI: 10.1002/ajoc.201300169] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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86
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Bachollet S, Terao K, Aida S, Nishiyama Y, Kakiuchi K, Oelgemöller M. Microflow photochemistry: UVC-induced [2 + 2]-photoadditions to furanone in a microcapillary reactor. Beilstein J Org Chem 2013; 9:2015-21. [PMID: 24204412 PMCID: PMC3817530 DOI: 10.3762/bjoc.9.237] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Accepted: 09/10/2013] [Indexed: 11/27/2022] Open
Abstract
[2 + 2]-Cycloadditions of cyclopentene and 2,3-dimethylbut-2-ene to furanone were investigated under continuous-flow conditions. Irradiations were conducted in a FEP-microcapillary module which was placed in a Rayonet chamber photoreactor equipped with low wattage UVC-lamps. Conversion rates and isolated yields were compared to analogue batch reactions in a quartz test tube. In all cases examined, the microcapillary reactor furnished faster conversions and improved product qualities.
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Affiliation(s)
- Sylvestre Bachollet
- James Cook University, School of Pharmacy and Molecular Sciences, Townsville, QLD 4811, Australia
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