DOCSLIB.ORG

REVIEW Multi-Photon Excitation in Photoredox Catalysis: Concepts, Applications, Methods

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
REVIEW Multi-Photon Excitation in Photoredox Catalysis: Concepts, Applications, Methods REVIEW Multi-Photon Excitation in Photoredox Catalysis: Concepts, Applications, Methods Felix Glaser,+[a] Christoph Kerzig,+[a] and Oliver S. Wenger*[a] + These two authors contributed equally. 1 REVIEW [a] F. Glaser, Dr. C. Kerzig, Prof. Dr. O. S. Wenger Department of Chemistry University of Basel St. Johanns-Ring 19, 4056 Basel (Switzerland) E-mail: [email protected] Abstract: The energy of visible photons and the accessible redox usually formed in micro-molar concentrations.[3] The potentials of common photocatalysts set thermodynamic limits to demonstration and popularization of triplet-triplet annihilation photochemical reactions that can be driven by traditional visible-light upconversion (TTA UC) in solution using continuous-wave (cw) irradiation. UV excitation can be damaging and induce side reactions, lasers represented an important advance because multi-photon hence visible or even near-IR light is usually preferable. Thus, processes became more widely amenable,[4] requiring neither photochemistry currently faces two divergent challenges, namely the pulsed lasers nor time-resolved spectrometers. Technological desire to perform ever more thermodynamically demanding advances leading to the availability of high-power LEDs with reactions with increasingly lower photon energies. The pooling of outputs covering the entire visible spectral range further two low-energy photons can address both challenges simultaneously, contributed to making multi-photon chemistry applicable in the and whilst multi-photon spectroscopy is well established, synthetic synthetic laboratory. The fact that such processes are now photoredox chemistry has only recently started to exploit multi- exploitable for preparative-scale conversions is remarkable and photon processes on the preparative scale. Herein, we have a represents a breakthrough in photochemistry. critical look at currently developed reactions and mechanistic The field of multi-photon excitation-based photoredox catalysis concepts, discuss pertinent experimental methods, and provide an is still very young, with studies reporting preparative-scale outlook into possible future developments of this rapidly emerging reactions only since 2014. Whilst the synthetic utility for area. thermodynamically challenging reactions seems undisputable, mechanistic aspects have led to several controversial discussions. The field would likely benefit from stronger interaction between synthetically oriented organic chemists on 1. Introduction the one hand and spectroscopists as well as physical-inorganic chemists on the other hand to tackle synthetic as well as Photoredox catalysis is an old concept that has been developed mechanistic challenges for new photochemical systems. In this [1] to a remarkable level of sophistication over the past decade. spirit and working near the interface of these sub-disciplines, we Now, some inherent thermodynamic limitations of traditional prepared this article. We provide an overview of the different visible-light irradiation strategies are becoming increasingly relevant concepts of multi-photon excitation and consider their evident. Two key factors govern these thermodynamic thermodynamic and kinetic particularities based on restrictions, namely the limited energy of visible photons (up to spectroscopic studies performed with laser techniques. 300 kJ/mol), and the excitation energy loss on the way from light Furthermore, we discuss their synthetic applications and absorption by the photosensitizer till substrate activation by the important mechanistic aspects, which seem crucial for allowing reacting catalyst species. As a rule of thumb, that energy loss further rational progress in this field. High-end as well as more amounts to at least 25 % (more typically about 50%) compared straightforward techniques for obtaining fundamental insight are to the initial photon energy, which is due to the accumulated outlined, and finally we contemplate possible future directions for energy losses caused by internal conversion, intersystem research on multi-photon excitation-based photoredox catalysis. crossing, and oxidation or reduction of the catalyst itself. Hence, We hope that this article will provide some useful guidance in the range of redox potentials in which robust visible-light identifying challenges, pitfalls, and opportunities in this emerging absorbing photocatalysts are operational is rather narrow. field. Increasing the photon energy is often not an option because many organic substrates directly absorb UV light, which can cause photo-damage and undesired side reactions. A more 2. Consecutive photo-excitation in the viable alternative is the development of tailor-made photoredox simplest case catalysts with aggressive redox properties, but this requires significant efforts and can jeopardize the stability of the All currently known preparative-scale photoredox reactions photocatalysts.[2] To drive thermodynamically increasingly relying on multi-photon excitation operate based on the challenging reactions with visible light and well-established consecutive (rather than simultaneous) absorption of photons. photocatalysts, the synthetically oriented photoredox community An overview of the photon densities required for consecutive therefore recently started to exploit multi-photon excitation. By (stepwise) two-photon absorption processes in the context of this strategy, the thermodynamic hurdles are overcome by photochromic reactions has been given recently,[5] and these combining the energy of two (or more) photons per catalytic light power considerations hold also true for the processes turnover. discussed herein. However, much higher excitation densities Spectroscopists have explored multi-photon processes in than provided by laboratory-fit LEDs and cw-lasers would be considerable depth, often with pulsed lasers that provided very required for simultaneous two-photon absorption to be high excitation densities, and short-lived photoproducts were efficient.[6] The sequence of ground-state absorption followed by 2 REVIEW excited state absorption events (upper and right part of Fig. 1) pulsed Nd:YAG laser that provided high excitation densities in therefore represents the conceptually most straightforward way short periods of time. to access highly energetic species. Such sequences have been explored extensively in the field of photon upconversion with Table 1. Reactions following the mechanism in Fig. 1 along with employed [7] lanthanide doped oxide or halide materials. Trivalent photocatalysts. lanthanides in these materials often exhibit multiple very long- lived f-f excited states, and therefore sizeable excited-state populations can build up even at moderate excitation powers, and this can be exploited for the conversion of near-infrared into visible or UV light. However, in molecular compounds in fluid solution, the lifetimes of electronically excited states are typically much shorter, and consequently the deceptively simple concept in Fig. 1 becomes tricky to realize for efficient preparative-scale chemical conversions. a ref. [9], b ref. [12], c ref. [13]. Figure 1. Simplified reaction via higher excited (triplet) states. PC = photoactive compound; the asterisk denotes an electronically excited state. Aiming to exploit the mechanism of Fig. 1 under continuous- wave (non-pulsed) irradiation conditions, we discovered that the [Ir(sppy) ] complex (Table 1, entry 2) catalyzes the formation of Photoionization studies with pulsed lasers provide quantitative 3 hydrated electrons in the presence of triethanolamine (TEAO) or insight into the sequential photon absorption implied in the ascorbate.[12] A diode laser (447 nm) sufficed for the 50 mg scale mechanism of Fig. 1. For instance with xanthone as photoactive photoreduction of 4-(trifluoromethyl)benzoate to the compound (PC), a first UV photon almost quantitatively corresponding difluoromethyl compound, as well as for the produces the lowest triplet (T ) state (*PC) with a lifetime () of 1 decomposition of a benzylammonium cation. Despite the ca. 20 µs in a methanol/water mixture, which can be further importance for pharma industry, only few good methods for the excited to a higher triplet (T ) by a secondary UV photon.[8] n selective activation of CF groups seem to be known yet,[14] and Ionization from the T state occurs with a quantum yield () of 3 n the structural motif of the benzylammonium cation is present in only 0.008 due to very rapid relaxation of that T state, yet the n many widely-used quaternary ammonium compounds,[15] which formation of hydrated electrons (e -) and oxidized xanthone aq need to be degraded in wastewater. Two-pulse two-color laser (PC+) was clearly detectable. However, photoredox catalysis flash photolysis provided unambiguous evidence for the was not performed with this system; the need for UV excitation mechanism in Fig. 1: An initial 430-nm pulse populates the and the low ionization quantum yield would represent significant 3MLCT excited state of [Ir(sppy)] with a lifetime of 1.6 µs, disadvantages. 3 exhibiting strong excited-state absorption between 460 and 570 The full catalytic cycle of Fig. 1 was completed in a system nm. In this wavelength range, the ground state does not absorb comprised of 3-aminoperylene (PerNH ) as photocatalyst and 2 hence a 532-nm secondary laser pulse selectively promotes ascorbate monoanion (HAsc-) as sacrificial electron donor, 3MLCT-excited [Ir(sppy) ] to a higher triplet excited state, from enabling the green-light induced decomposition of chloroacetate
Load more

Recommended publications
  • Photoredox Catalysis Photoredox Catalysis: a Mild, Operationally Simple Approach to the Synthesis of A-Trifluoromethyl Carbonyl Compounds Phong V
    DOI: 10.1002/anie.201101861 Photoredox Catalysis Photoredox Catalysis: A Mild, Operationally Simple Approach to the Synthesis of a-Trifluoromethyl Carbonyl Compounds Phong V. Pham, David A. Nagib, and David W. C. MacMillan* The unique physical and chemical advantages conferred by the CÀF bond have led to the broad exploitation of this motif throughout the pharmaceutical,[1] materials,[2] and agrochem- ical[3] sectors. In drug design, for instance, incorporation of polyfluorinated alkyl groups, such as CF3 moieties, can profoundly impact the activity, metabolic stability, lipophilic- ity, and bioavailability of lead compounds.[1,4] Not surpris- ingly, the development of methods for the production of carbonyl-based synthons bearing a-CF3 substitution has emerged as a central objective in the field of chemical synthesis. Although important recent advances have been made toward this goal, there are currently few operationally simple methods for the conversion of enolates (or enolate equivalents) to a-trifluoromethylated carbonyl motifs. Stan- dard alkylation methods are generally not productive, due to the negative polarization of the trifluoromethyl moiety, thus specially tailored reagents have been developed to furnish an trifluoromethylation of a range of enolates or enolate [5] electrophilic CF3 equivalent. Alternatively, in recent years, a equivalents [Eq. (1)]. In this context, we elected to employ set of radical (Et3B/O2) and organometallic (Rh-catalyzed) enolsilanes and silylketene acetals as suitable enolic sub- approaches have been
    [Show full text]
  • Enantioselective Alkylation of Aldehydes
    Angewandte Chemie International Edition: DOI: 10.1002/anie.201503789 Synthetic Methods Hot Paper German Edition: DOI: 10.1002/ange.201503789 Enantioselective a-Alkylation of Aldehydes by Photoredox Organocatalysis: Rapid Access to Pharmacophore Fragments from b- Cyanoaldehydes** Eric R. Welin, Alexander A. Warkentin, Jay C. Conrad, and David W. C. MacMillan* Abstract: The combination of photoredox catalysis and Recently, we questioned whether this dual photoredox- enamine catalysis has enabled the development of an enantio- organocatalysis platform could be translated to the asym- selective a-cyanoalkylation of aldehydes. This synergistic metric catalytic alkylation of aldehydes using a-bromo catalysis protocol allows for the coupling of two highly cyanoalkyls, a protocol that would generate b-cyanoalde- versatile yet orthogonal functionalities, allowing rapid diversi- hydes in one step. As a critical design element, we recognized fication of the oxonitrile products to a wide array of that a-bromo cyanoalkylating reagents would not be suitable medicinally relevant derivatives and heterocycles. This meth- electrophiles for most catalytic enolate addition pathways; odology has also been applied to the total synthesis of the however, the corresponding open-shell radicals, derived by lignan natural product (À)-bursehernin. one-electron reduction of a-bromonitriles, should readily undergo coupling with transiently generated chiral enamines. The enantioselective a-alkylation of carbonyl compounds In addition, the nitrile functional group offers
    [Show full text]
  • Electrochemistry and Photoredox Catalysis: a Comparative Evaluation in Organic Synthesis
    molecules Review Electrochemistry and Photoredox Catalysis: A Comparative Evaluation in Organic Synthesis Rik H. Verschueren and Wim M. De Borggraeve * Department of Chemistry, Molecular Design and Synthesis, KU Leuven, Celestijnenlaan 200F, box 2404, 3001 Leuven, Belgium; [email protected] * Correspondence: [email protected]; Tel.: +32-16-32-7693 Received: 30 March 2019; Accepted: 23 May 2019; Published: 5 June 2019 Abstract: This review provides an overview of synthetic transformations that have been performed by both electro- and photoredox catalysis. Both toolboxes are evaluated and compared in their ability to enable said transformations. Analogies and distinctions are formulated to obtain a better understanding in both research areas. This knowledge can be used to conceptualize new methodological strategies for either of both approaches starting from the other. It was attempted to extract key components that can be used as guidelines to refine, complement and innovate these two disciplines of organic synthesis. Keywords: electrosynthesis; electrocatalysis; photocatalysis; photochemistry; electron transfer; redox catalysis; radical chemistry; organic synthesis; green chemistry 1. Introduction Both electrochemistry as well as photoredox catalysis have gone through a recent renaissance, bringing forth a whole range of both improved and new transformations previously thought impossible. In their growth, inspiration was found in older established radical chemistry, as well as from cross-pollination between the two toolboxes. In scientific discussion, photoredox catalysis and electrochemistry are often mentioned alongside each other. Nonetheless, no review has attempted a comparative evaluation of both fields in organic synthesis. Both research areas use electrons as reagents to generate open-shell radical intermediates. Because of the similar modes of action, many transformations have been translated from electrochemical to photoredox methodology and vice versa.
    [Show full text]
  • A Synergistic LUMO Lowering Strategy Using Lewis Acid Catalysis in Water to Enable Photoredox Cite This: Chem
    Chemical Science View Article Online EDGE ARTICLE View Journal | View Issue A synergistic LUMO lowering strategy using Lewis acid catalysis in water to enable photoredox Cite this: Chem. Sci.,2018,9,7096 – All publication charges for this article catalytic, functionalizing C C cross-coupling of have been paid for by the Royal Society † of Chemistry styrenes Elisabeth Speckmeier, Patrick J. W. Fuchs and Kirsten Zeitler * Easily available a-carbonyl acetates serve as convenient alkyl radical source for an efficient, photocatalytic cross-coupling with a great variety of styrenes. Activation of electronically different a-acetylated acetophenone derivatives could be effected via LUMO lowering catalysis using a superior, synergistic combination of water and (water-compatible) Lewis acids. Deliberate application of fac-Ir(ppy)3 as photocatalyst to enforce an oxidative quenching cycle is crucial to the success of this (umpolung type) transformation. Mechanistic particulars of this dual catalytic coupling reaction have been studied in detail using both Stern–Volmer and cyclic voltammetry Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Received 12th May 2018 experiments. As demonstrated in more than 30 examples, our water-assisted LA/photoredox Accepted 17th July 2018 catalytic activation strategy allows for excess-free, equimolar radical cross-coupling and subsequent DOI: 10.1039/c8sc02106f formal Markovnikov hydroxylation to versatile 1,4-difunctionalized products in good to excellent rsc.li/chemical-science yields. redox properties: with an oxidation potential of only 0.66 V vs. Introduction À SCE (Eox(Brc/Br ) ¼ 0.66 V) mesolytically cleaved bromide Visible light photocatalysis as a powerful tool for the selective anions can easily get oxidized to the corresponding bromine This article is licensed under a generation of radicals has given rise to numerous unprece- radicals and hence potentially may also form elemental Br2 by 8–10 dented C–C-coupling reactions in recent years.1 Especially alkyl most common photocatalysts.
    [Show full text]
  • Merging Photoredox Catalysis with Organocatalysis
    REPORTS 8. C. Resini, T. Montanari, G. Busca, J.-M. Jehng, 17. M. Salmeron, R. Schlögl, Surf. Sci. Rep. 63, 169 (2008). für Synchrotronstrahlung for support of in situ XPS I. E. Wachs, Catal. Today 99, 105 (2005). 18. T. I. T. Okpalugo, P. Papakonstantinou, H. Murphy, measurements; and M. A Smith for helpful discussions. 9. T. G. Alkhazov, E. A. Ismailov, A. Yu, A. I. Kozharov, J. McLaughlin, N. M. D. Brown, Carbon 43, 153 (2005). Supported by the CANAPE project of the 6th Framework Kinet. Katal. 19, 611 (1978). 19. L. M. Madeira, M. F. Portela, Catal. Rev. 44, 247 (2002). Programme of European Commission and the ENERCHEM 10. M. S. Kane, L. C. Kao, R. K. Mariwala, D. F. Hilscher, 20. F. Atamny et al., Mol. Phys. 76, 851 (1992). project of the Max Planck Society. H. C. Foley, Ind. Eng. Chem. Res. 35, 3319 (1996). 21. M. L. Toebes, J. M. P. van Heeswijk, J. H. Bitter, 11. M. F. R. Pereira, J. J. M. Órfão, J. L. Figueiredo, A. J. van Dillen, K. P. de Jong, Carbon 42, 307 (2004). Appl. Catal. A 218, 307 (2001). 22. A. M. Puziy, O. I. Poddubnaya, A. M. Ziatdinov, Appl. Surf. Supporting Online Material www.sciencemag.org/cgi/content/full/322/5898/73/DC1 12. J. Zhang et al., Angew. Chem. Int. Ed. 46, 7319 (2007). Sci. 252, 8036 (2006). Materials and Methods 13. G. Mestl, N. I. Maksimova, N. Keller, V. V. Roddatis, 23. S. J. Clark et al., Z. Kristallogr. 220, 567 (2005). R. Schlögl, Angew.
    [Show full text]
  • Visible Light Photoredox Catalysis with Transition Metal Complexes: Applications in Organic Synthesis Christopher K
    Review pubs.acs.org/CR Visible Light Photoredox Catalysis with Transition Metal Complexes: Applications in Organic Synthesis Christopher K. Prier, Danica A. Rankic, and David W. C. MacMillan* Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States References 5360 1. INTRODUCTION CONTENTS A fundamental aim in the field of catalysis is the development 1. Introduction 5322 of new modes of small molecule activation. One approach 2+ toward the catalytic activation of organic molecules that has 2. Photochemistry of Ru(bpy)3 5323 3. Net Reductive Reactions 5324 received much attention recently is visible light photoredox 3.1. Reduction of Electron-Poor Olefins 5324 catalysis. In a general sense, this approach relies on the ability of 3.2. Reductive Dehalogenation 5326 metal complexes and organic dyes to engage in single-electron- 3.3. Reductive Cleavage of Sulfonium and transfer (SET) processes with organic substrates upon Sulfonyl Groups 5328 photoexcitation with visible light. 3.4. Nitrogen Functional Group Reductions 5329 Many of the most commonly employed visible light 3.5. Radical Cyclizations 5330 photocatalysts are polypyridyl complexes of ruthenium and iridium, and are typified by the complex tris(2,2′-bipyridine) 3.6. Reductive Epoxide and Aziridine Opening 5331 2+ 3.7. Reduction-Labile Protecting Groups 5331 ruthenium(II), or Ru(bpy)3 (Figure 1). These complexes 4. Net Oxidative Reactions 5332 4.1. Functional Group Oxidations 5332 4.2. Oxidative Removal of the PMB Group 5334 4.3. Oxidative Biaryl Coupling 5335 4.4. Oxidative Generation of Iminium Ions 5335 4.5. Azomethine Ylide [3 + 2] Cycloadditions 5338 4.6.
    [Show full text]
  • Difunctionalization of Alkenes and Alkynes Via Intermolecular Radical and Nucleophilic Additions
    molecules Review Difunctionalization of Alkenes and Alkynes via Intermolecular Radical and Nucleophilic Additions Hongjun Yao 1,†, Wenfei Hu 2,† and Wei Zhang 2,* 1 College of Biological Science and Technology, Beijing Forestry University, 35 Qinghua East Road, Beijing 100083, China; [email protected] 2 Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston, MA 02125, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-617-287-6147 † These authors contributed equally to this work. Abstract: Popular and readily available alkenes and alkynes are good substrates for the preparation of functionalized molecules through radical and/or ionic addition reactions. Difunctionalization is a topic of current interest due to its high efficiency, substrate versatility, and operational simplicity. Presented in this article are radical addition followed by oxidation and nucleophilic addition reactions for difunctionalization of alkenes or alkynes. The difunctionalization could be accomplished through 1,2-addition (vicinal) and 1,n-addition (distal or remote) if H-atom or group-transfer is involved in the reaction process. A wide range of moieties, such as alkyl (R), perfluoroalkyl (Rf), aryl (Ar), hydroxy (OH), alkoxy (OR), acetatic (O2CR), halogenic (X), amino (NR2), azido (N3), cyano (CN), as well as sulfur- and phosphorous-containing groups can be incorporated through the difunctional- ization reactions. Radicals generated from peroxides or single electron transfer (SET) agents, under photoredox or electrochemical reactions are employed for the reactions. Keywords: difunctionalization; radical; nucleophilic; alkene; alkyne; photoredox; single electron transfer; vicinal-difunctionalization; distal-difunctionalization; photoredox; electrochemical reaction Citation: Yao, H.; Hu, W.; Zhang, W. Difunctionalization of Alkenes and Alkynes via Intermolecular Radical and Nucleophilic Additions.
    [Show full text]
  • Photoredox Catalysis in Organic Chemistry Megan H
    This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. Perspective pubs.acs.org/joc Photoredox Catalysis in Organic Chemistry Megan H. Shaw, Jack Twilton, and David W. C. MacMillan* Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States ABSTRACT: In recent years, photoredox catalysis has come to the forefront in organic chemistry as a powerful strategy for the activation of small molecules. In a general sense, these approaches rely on the ability of metal complexes and organic dyes to convert visible light into chemical energy by engaging in single-electron transfer with organic substrates, thereby generating reactive intermediates. In this Perspective, we highlight the unique ability of photoredox catalysis to expedite the development of completely new reaction mechanisms, with particular emphasis placed on multicatalytic strategies that enable the construction of challenging carbon−carbon and carbon− heteroatom bonds. ■ INTRODUCTION this catalytic platform to organic synthesis begun to be fully Over the last century, the discovery, development, and use of realized. A key factor in the recent yet rapid growth of this activation platform has been the recognition that readily light-mediated catalysis has enabled the invention of a wide accessible metal polypyridyl complexes and organic dyes can variety of nontraditional bond constructions in organic facilitate the conversion
    [Show full text]
  • COMMUNICATION Asymmetric Organocatalysis and Photoredox
    Asymmetric Organocatalysis and Photoredox Catalysis for the α-Functionalization of Tetrahydroisoquinolines Item Type Article Authors Hou, Hong; Zhu, Shaoqun; Atodiresei, Iuliana; Rueping, Magnus Citation Hou H, Zhu S, Atodiresei I, Rueping M (2018) Asymmetric Organocatalysis and Photoredox Catalysis for the α- Functionalization of Tetrahydroisoquinolines. European Journal of Organic Chemistry 2018: 1277–1280. Available: http:// dx.doi.org/10.1002/ejoc.201800117. Eprint version Post-print DOI 10.1002/ejoc.201800117 Publisher Wiley Journal European Journal of Organic Chemistry Rights This is the peer reviewed version of the following article: Asymmetric Organocatalysis and Photoredox Catalysis for the α-Functionalization of Tetrahydroisoquinolines, which has been published in final form at http://doi.org/10.1002/ejoc.201800117. This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving. Download date 29/09/2021 05:30:43 Link to Item http://hdl.handle.net/10754/627347 COMMUNICATION Asymmetric Organocatalysis and Photoredox Catalysis for the α- Functionalization of Tetrahydroisoquinolines Hong Hou,[a,b] Shaoqun Zhu,[a] Iuliana Atodiresei[a] and Magnus Rueping[a,c]* Abstract: The asymmetric α-alkylation of tetrahydroisoquinolines with particular, cyclic ketones were selected which are more cyclic ketones has been accomplished in the presence of a combined challenging substrates in the enantioselective oxidative coupling catalytic system consisting of a visible-light photoredox catalyst and a reaction with tertiary amines (Scheme 1).[12] chiral primary amine organocatalyst. The desired products were obtained in good yields, high enantioselectivity and good to excellent diastereoselectivity. O + hv, Photocatalyst Ar N * Ar Organocatalyst O * The harnessing of visible light sensitization as a powerful strategy for initiating organic reactions is attractive and becoming an important tool in synthesis due to its favorable features, including low cost, convenience and environmentally Scheme 1.
    [Show full text]
  • Advances in Visible-Light-Mediated Carbonylative Reactions Via Carbon Monoxide (CO) Incorporation
    catalysts Review Advances in Visible-Light-Mediated Carbonylative Reactions via Carbon Monoxide (CO) Incorporation Vinayak Botla 1, Aleksandr Voronov 1, Elena Motti 1, Carla Carfagna 2, Raffaella Mancuso 3 , Bartolo Gabriele 3 and Nicola Della Ca’ 1,* 1 Department of Chemistry, Life Sciences and Environmental Sustainability (SCVSA), University of Parma, Parco Area delle Scienze, 17/A, 43124 Parma, Italy; [email protected] (V.B.); [email protected] (A.V.); [email protected] (E.M.) 2 Department of Industrial Chemistry “T. Montanari”, University of Bologna, 40136 Bologna, Italy; [email protected] 3 Laboratory of Industrial and Synthetic Organic Chemistry (LISOC), Department of Chemistry and Chemical Technologies, University of Calabria, Via P. Bucci 12/C, 87036 Arcavacata di Rende Cosenza, Italy; [email protected] (R.M.); [email protected] (B.G.) * Correspondence: [email protected]; Tel.:+39-0521-905676 Abstract: The abundant and inexpensive carbon monoxide (CO) is widely exploited as a C1 source for the synthesis of both fine and bulk chemicals. In this context, photochemical carbonylation reactions have emerged as a powerful tool for the sustainable synthesis of carbonyl-containing compounds (esters, amides, ketones, etc.). This review aims at giving a general overview on visible light-promoted carbonylation reactions in the presence of metal (Palladium, Iridium, Cobalt, Ruthenium, Copper) and organocatalysts as well, highlighting the main features of the presented protocols and providing Citation: Botla, V.; Voronov, A.; useful insights on the reaction mechanisms. Motti, E.; Carfagna, C.; Mancuso, R.; Gabriele, B.; Della Ca’, N. Advances Keywords: carbon monoxide; carbonylation; photochemical reactions; visible light; carbonyl- in Visible-Light-Mediated containing compounds Carbonylative Reactions via Carbon Monoxide (CO) Incorporation.
    [Show full text]
  • Photoredox-Catalyzed Oxo-Amination of Aryl Cyclopropanes
    ARTICLE https://doi.org/10.1038/s41467-019-12403-2 OPEN Photoredox-catalyzed oxo-amination of aryl cyclopropanes Liang Ge1, Ding-Xing Wang1, Renyi Xing1,DiMa1, Patrick J. Walsh 2* & Chao Feng 1* Cyclopropanes represent a class of versatile building blocks in modern organic synthesis. While the release of ring strain offers a thermodynamic driving force, the control of selectivity for C–C bond cleavage and the subsequent regiochemistry of the functionalization remains fi 1234567890():,; dif cult, especially for unactivated cyclopropanes. Here we report a photoredox-coupled ring- opening oxo-amination of electronically unbiased cyclopropanes, which enables the expe- dient construction of a host of structurally diverse β-amino ketone derivatives. Through one electron oxidation, the relatively inert aryl cyclopropanes are readily converted into reactive radical cation intermediates, which in turn participate in the ensuing ring-opening functio- nalizations. Based on mechanistic studies, the present oxo-amination is proposed to proceed through an SN2-like nucleophilic attack/ring-opening manifold. This protocol features wide substrate scope, mild reaction conditions, and use of dioxygen as an oxidant both for catalyst regeneration and oxygen-incorporation. Moreover, a one-pot formal aminoacylation of olefins is described through a sequential cyclopropanation/oxo-amination. 1 Institute of Advanced Synthesis (IAS), School of Chemistry and Molecular Engineering, Nanjing Tech University, 30 South Puzhu Road, 211816 Nanjing,P.R. China. 2 Roy and
    [Show full text]
  • A Combination of Visible‐Light Organophotoredox Catalysis And
    A Combination of Visible‐Light Organophotoredox Catalysis and Asym‐ metric Organocatalysis for the Enantioselective Mannich Reaction of Dihydroquinoxalinones with Ketones. Jaume Rostoll-Berenguer,a Gonzalo Blay,a M. Carmen Muñoz,b José R. Pedro,a* Carlos Vilaa* a Departament de Química Orgànica, Facultat de Química, Universitat de València, Dr. Moliner 50, 46100 Burjassot, Valèn- cia (Spain). E-mail: [email protected], [email protected], b Departament de Física Aplicada, Universitat Politècnica de València, Camino de Vera s/n, 46022 València (Spain). Supporting Information Placeholder ABSTRACT: An enantioselective photooxidative Mannich reaction of dihydroquinoxalinones with ketones by the merger of organ- ophotoredox and asymmetric organocatalysis is described. This protocol features a very mild reaction conditions using simple and cheap catalysts (Eosin Y and (S)-Proline) for the synthesis of chiral quinoxaline derivatives with good to high yields (up to 94%) and excellent enantioselectivities (up to 99% ee). The employment of visible-light photoredox catalysis have The enantioselective synthesis of chiral amines is, generally, become a hot topic in synthetic chemistry in the last decade, due a remarkable research area owing to the importance of chiral to its significant advantages such as low cost, safe, renewable, nitrogen‐containing compounds for medicinal, pharmaceutical abundant, and environmentally friendliness. 1,2 On the other and agrochemical chemistry.8 In this context, since the pioneer- hand, control of chirality is one
    [Show full text]