Photoredox Catalysis for Novel Organic Reactions

Beilstein Organic Chemistry Symposium 2018

24 – 26 April, 2018
avendi Hotel am Griebnitzsee, Potsdam, Germany

 

Scientific Program:

Markus Antonietti and Peter H. Seeberger / Max Planck Institute of Colloids and Interfaces

Summary

The Beilstein organic chemistry symposium on photoredox catalysis for novel organic reactions was held at the avendi Hotel in Potsdam on the banks of the Griebnitzsee from April 24th - 26th 2018. The meeting, which had been organized by Markus Antonietti and Peter H. Seeberger, brought together a diverse group of scientists including organic chemists, material scientists and chemical engineers. Around 100 participants from 19 countries had the chance to experience outstanding presentations from leading researchers in the field and were also able to observe the latest developments of talented students and postdoctoral researchers during two well-attended poster sessions. The limited attendance list fostered stimulating discussions and an interdisciplinary interchange which often lasted late until the night.

This Beilstein symposium covered a broad range of topics including catalyst development, novel transformations and dedicated technologies for photochemical transformations. Although the first day was mainly dedicated to the use of light for organic synthesis, the attendees could already gather a glimpse of the diversity of the state-of-the-art research in photochemistry during the first session. A lecture on the use of flow reactors for semi-syntheses of antimalarial drugs by Peter H. Seeberger was followed by a talk from Elizabeth von Hauff on optical and electrical spectroscopic techniques to locate and study electron transfer in nanostructured semiconductors. Corey Stephenson, Burkhard König and Magnus Rueping discussed their efforts on the development of new methodologies for the synthesis of complex organic molecules via visible light photoredox catalysis using a diverse set of photocatalysts including transition metal base polypyridyl complexes, semiconducting materials and organic dyes. Axel G. Griesbeck gave insights in the application of molecular oxygen as electron or energy acceptor, sacrificial oxidant and redox mediator in multiple transformations. In his talk, Shawn K. Collins elaborated on the development and evaluation of heteroleptic copper complexes as photoredox catalysts and concluded that the prediction of catalyst efficiency based on photophysical data is limited.

The second day was kicked off by Gary A. Molander who impressively demonstrated how to overcome some of the bottlenecks of palladium-catalyzed cross-coupling reactions via dual photoredox and nickel catalysis. This powerful approach is on the way to being implemented in the synthesis of fine chemicals such as active pharmaceutical ingredients.  Technological challenges for large scale synthetic photochemistry were discussed by Kevin Booker-Milburn who showed how his group overcomes scalability issues with novel flow reactor technologies. Along those lines Timothy Noel presented flow devices made out of luminescent solar concentrators for efficiently harvesting sunlight even at cloudy days. Matthias Drieß pointed out that it also necessary to find efficient ways to degrade organic molecules for waste water treatment and discussed his efforts in this field of imminent high interest and further reported on water-splitting by heterogeneous photocatalysis. For the latter, many catalytic systems are currently intensively studied. Marcella Bonchio taught the audience about the combination of water soluble ruthenium photosensitizers with oxygenic polyoxometalates to boost artificial photosynthesis and Xinchen Wang and Siddulu Naidu Talapaneni presented their research on carbon nitride materials as promising metal-free alternatives.

A further highlight on the second day was a stimulating panel discussion moderated by Markus Antonietti. The underlying question was why, although known for a long time, photoredox catalysis and photochemistry in general is currently one of the most prominent and active fields and if this resurgence is just “hype” or a promising approach to change the face of chemistry in the future. One of the general conclusions which can be drawn from this debate is that the reincarnation of photochemistry stems from the simultaneous development of new technologies and catalysts as well as weaker boundaries between the research disciplines. It was stressed that photocatalysis is still often an unpredictable, empirical science with little understanding of the underlying mechanisms. In order to fill this knowledge gap the attendees called for more emphasis on in-depth mechanistic studies and the development of new spectroscopic techniques, and also for a better education of students in the field of radical chemistry. 

The program of the last day started with a presentation on “continuous flow photoredox catalysis” by Timothy F. Jamison and his efforts to use CO2 as a building block in organic synthesis. Kirsten Zeitler showed the development of multicatalytic transformations using homogeneous photoredox catalysts using Umpolung strategies and orthogonal activation. A combination of carbon nitrides and functionalized ruthenium complexes was applied by Kazuhiko Maeda for CO2 reductions who also reported on the oxidation of water using a Co(OH)2/TiO2 photocatalyst which can absorb visible light up to 850 nm. Christian V. Stevens presented not only a microreactor technology for increased photon efficiency but also discussed why flow chemistry can be useful for scaling non-photochemical reactions. In the afternoon a variety of photocatalytic systems for synthetic applications were discussed; The combination of photo- and Lewis acid catalysis played a central role during Tehshik Yoon’s excellent lecture on enantioselective photocycloadditions via single electron or energy transfer events. David Nicewicz focused on the utilization of acridinium salts as photocatalysts for powerful synthetic transformations. He was followed by Kerry Gilmore, Aleksandr Savateev and Markus Antonietti who gave insights in the utilization of carbon nitride materials as heterogeneous photocatalysts for organic synthesis.

The lively and thought-provoking conference achieved its goal in generating stimulating discussions and building a bridge between diverse communities who are working on new organic reactions, synthesizing novel photocatalysts or designing devices and processes to optimize the chemical engineering of photocatalysis.

The conference will also act as a catalyst for a thematic issue in the Beilstein Journal of Organic Chemistry, where original work on “Photoredox catalysis for novel organic reactions” will be published.

Bartholomäus Pieber
Max Planck Institute of Colloids and Interfaces

Scientific Program

Talks

TUESDAY, 24 April

 
Welcome and Introduction

Chair: Christoforos Kokotos

Continuous flow photochemistry
Peter H. Seeberger / Max Planck Institute of Colloids and Interfaces

Organic and hybrid systems for solar energy conversion
Elizabeth von Hauff / Vrije Universiteit Amsterdam

Redox catalysis strategies for complex molecules
Corey Stephenson / University of Michigan

Molecular oxygen in photo (redox) catalysis: electron vs. energy acceptor reagent, sacrificial component, or (only) redox mediator
Axel G. Griesbeck / University of Cologne

Chair: Till Opatz

Photoredox catalysis for C–C and C–heteroatom bond formations
Magnus Rueping / RWTH Aachen University

Novel functional nanoporous carbon nitride and their catalytic applications
Siddulu Naidu Talapaneni / University of Newcastle

Copper-based complexes in photocatalysis
Shawn K. Collins / Université de Montréal

Photoredox catalysis with one or more photons and electrons
Burkhard König / University Regensburg

POSTER SESSION

Wednesday, 25 April

 

Chair: Stella Vukelic

Single electron processes enabling organic synthesis
Gary A. Molander / University of Pennsylvania

From photocatalytic water-splitting to advances in water-waste treatment
Matthias Drieß / Technical University of Berlin

Batch and flow photoreactors for generating molecular complexity
Kevin Booker-Milburn / University of Bristol

Graphitic carbon nitride polymers for sustainable photoredox catalysis
Xinchen Wang / Fuzhou University

Chair: Bernhard Wetsermann

Bio-inspired nano-architectures for artificial photosynthesis
Marcella Bonchio / University of Padova

Visible-light photoredox catalysis in flow – towards a sustainable production of pharmaceuticals
Timothy Noël / Eindhoven University of Technology

PANEL DISCUSSION

POSTER SESSION

Thursday, 26 April

 

Chair: Dorota Gryko

Continuous flow photoredox catalysis
Timothy F. Jamison / Massachusetts Institute of Technology

New approaches for visible light mediated multicatalytic transformations
Kirsten Zeitler / Leipzig University

Surface modified semiconductor photocatalysts for carbon dioxide reduction and water oxidation
Kazuhiko Maeda / Tokyo Institute of Technology

Continuous flow chemistry: opening doors towards “non-scalable” chemistry
Christian V. Stevens / Ghent University

Chair: François Lévesque

Chemoselective photoredox transformations
Kerry Gilmore / Max Planck Institute of Colloids and Interfaces

Novel organic reactions with a heterogeneous poly(heptazine imide) photocatalyst
Aleksandr Savateev / Max Planck Institute of Colloids and Interfaces

Stereocontrol in photochemical reactions
Tehshik P. Yoon / University of Wisconsin-Madison

New avenues in synthesis via organic photoredox catalysis
David Nicewicz / University of North Carolina

Homogeneous versus heterogeneous photocatalysis: sustainability and new reactions
Markus Antonietti / Max Planck Institute of Colloids and Interfaces

Final Words, Farewell

Poster

Part 1 - Tuesday, 24 April

 

No. 1:
Hybrid semiconductor nanomaterials for photocatalytic organic transformations
Amedeo Agosti, University of Bologna

No. 2:
Continuous-flow photooxidation of conjugated and isolated alkenes with singlet oxygen in a micro flow reactor
Patrick Bayer, University of Regensburg

No. 3:
DiCyanoPyrazine: new and highly efficient organic photoredox catalyst
Filip Bureš, University of Pardubice

No. 4:
Radical-based C–C bond forming processes enabled by the photoexcitation of 4-alkyl-1,4-dihydropyridines
Luca Buzzetti, Institute of Chemical Research of Catalonia

No. 5:
Selective single C(sp3)–F bond cleavage in trifluoromethylarenes by merging visible light catalysis with Lewis acid activation
Kang Chen, University of Regensburg

No. 6:
Direct asymmetric C–H functionalization of toluene derivatives via excited iminium ions catalysis
Giacomo E. M. Crisenza, Institute of Chemical Research of Catalonia

No. 7:
Practical and convenient photoinduced direct oximation of cyclohexane
Somnath Das, Heidelberg University

No. 8:
Decarboxylative alkynylation of carboxylic acids using hypervalent iodine and photoredox catalysis
Marion Garreau, EPFL - École polytechnique fédérale de Lausanne

No. 9:
Organic dyes in reductive C–H arylations
Indrajit Ghosh, Max Planck Institute of Colloids and Interfaces

No. 10:
Enabling fragment growth with photoredox catalysis
Rachel Grainger, Astex Pharmaceuticals, Cambridge

No. 11:
Porphyrins as photoredox catalysts for efficient C–C bond forming reactions
Dorota Gryko, Polish Academy of Sciences

No. 12:
Reductive amination by photoredox catalysis
Xingwei Guo, University of Basel

No. 13:
Structural modifications of pyrazine-2,3-dicarbonitrile: towards a series of efficient photoredox catalysts
Zuzana Hloušková, University of Pardubice

No. 14:
Visible light activation for the preparation and activation of fluorinated compounds
Mattthew N. Hopkinson, Free University of Berlin

No. 15:
Photoredox-mediated tandem three-component process
Lucie Jarrige, University of Paris-Saclay

No. 16:
Covalent proteases inhibitors through photoredox-mediated late stage functionalization
Lisa Marie Kammer, Johannes Gutenberg University Mainz

No. 17:
Phenylglyoxylic acid as a photocatalyst for novel organic transformations
Christoforos G. Kokotos, National and Kapodistrian University of Athens

No. 18:
Carbon nitride-hydrogen peroxide adduct for selective photo-oxidation
Igor Krivtsov, University of Oviedo

No. 19:
Visible-light-mediated aerobic glycosylation catalyzed by iodine: employing iodine as an efficient photocatalyst
Matthias Krumb, Johannes Gutenberg University Mainz

No. 20:
Thiophene derivatives as a metal-free alternative for photocatalytic application
Ewelina Kuna, University of Bologna

No. 21:
Visible-light CO2 reduction using hybrid photocatalysts constructed with carbon nitride and Ru(II) binuclear complex
Ryo Kuriki, Tokyo Institute of Technology

No. 22:
An approach to thioamide and oxadiazole synthesis using carbon nitride as heterogeneous photocatalyst
Bogdan Kurpil, Max Planck Institute of Colloids and Interfaces

No. 23:
Metal-free photoredox-catalyzed cyanation alkynylation of oxime ethers via iminyl radical-initiated cascade
Franck Le Vaillant, EPFL – École polytechnique fédérale de Lausanne

No. 24:
Photoredox catalysis in α-amine functionalisation
Jamie A. Leitch, University of Oxford

No. 25:
Correlating the surface basicity of metal oxides with photocatalytic hydroxylation
Wan Ru Leow, Nanyang Technological University

No. 26:
Photochemistry as an enabling and scalable tool
François Lévesque, MSD, Rahway

No. 27:
Preparation of photoactive materials based on different supramolecular complexes
Lina Li, Max Planck Institute of Colloids and Interfaces

No. 28:
Metal-free aerobic photocyanation of tertiary amines and its application to the syntheses of natural products
Alexander Lipp, Johannes Gutenberg University Mainz

Part 2 - Wednesday, 25 April

 

No. 29:
Light-induced alkylation of (hetero)aromatic nitriles in a transition-metal-free C–C-bond metathesis
Benjamin Lipp, Johannes Gutenberg University Mainz

No. 30:
Organocatalytic enantioselective alkylation of aldehydes with [Fe(bpy)3]Br2 catalyst and visible light
Marianna Marchini, University of Bologna

No. 31:
Photosynthesis with rust: photo-oxidation of organic substrates by nanostructured hematite photoanodes
Raffaello Mazzaro, Luleå University of Technology

No. 32:
Carboxylation of bromides or styrenes with CO2 by dual visible-light–nickel catalysis
Qing-Yuan Meng, University of Regensburg

No. 33:
Dichromatic photocatalytic substitutions of aryl halides with a small organic dye
Michael Neumeier, University of Regensburg

No. 34:
Study on design and mechanism of metal-free photocatalytic fluoroalkylation of olefins
Naoki Noto, Tokyo Institute of Technology

No. 35:
TiO2 photocatalysis in the aromatic “redox tag”-guided intermolecular formal  [2 + 2] cycloadditions
Yohei Okada, Tokyo University of Agriculture and Technology

No. 36:
Continuous heterogeneous photoredox catalysis in serial-micro batch reactors
Bartholomäus Pieber, Max Planck Institute of Colloids and Interfaces

No. 37:
Intermolecular radical addition to carbonyls enabled by visible light photoredox initiated hole catalysis
Lena Pitzer, University of Münster

No. 38:
Visible-light-mediated Achmatowicz rearrangement
Matthew Plutschak, Max Planck Institute for Coal Research

No. 39:
Intensification of photoredox reactions: from rapid optimization in batch to a highly efficient continuous flow process
Juan A. Rincón, Eli Lilly and Company

No. 40:
Selective activation of sulfur hexafluoride – addition of SF6 to styrenes using photoredox catalysis
David Rombach, Karlsruhe Institute of Technology

No. 41:
"Everlasting" carbon nitride radical anion - a key player in visible light photocatalytic CH bond activation
Aleksandr Savateev, Max Planck Institute of Colloids and Interfaces

No. 42:
Metal-free visible-light-induced aerobic photo-oxidation of β-aminoketones to enaminones and its application to the synthesis of N-heterocycles
Adrian Sevenich, Johannes Gutenberg University Mainz

No. 43:
Irradiation-excited palladium-catalysis through blending radical and organometallic reactivity
Rui Shang, University of Tokyo

No. 44:
sp3 C–H functionalization enabled by metallatriplet catalysis
Yangyang Shen, Institute of Chemical Research of Catalonia

No. 45:
Oxidative organophotoredox catalysis: a visible light initiated, new strategy for the synthesis of quinoxaline derivatives via aerobic oxidation
Jaya Singh, LRPG College Sahibabad

No. 46:
Eosin B  catalysed: a regioselective synthesis of  substituted  imidazopyridinesc, initiated by visible light
Madhulika Srivastava, State University of Allahabad

No. 47:
Visible-light-mediated synthesis of nitrogen containing molecules using amidyl and aminium radicals
Thomas D. Svejstrup, University of Manchester

No. 48:
The energy transfer enabled biocompatible disulfide–ene reaction
Michael Teders, University of Münster

No. 49:
Reaction quantum yield as key for the mechanistic understanding of organic-chemical photoredox catalysis
Hans-Achim Wagenknecht, Karlsruhe Institute of Technology

No. 50:
Site-selective C–C bond formation in unprotected monosaccharides using photoredox catalysis
Ieng Chim Wan, Stratingh Institute for Chemistry

No. 51:
Unlocking the elusive generation of carbyne equivalents with photoredox catalysis
Zhaofeng Wang, Institute of Chemical Research of Catalonia

No. 52:
Direct synthesis of graphene-based 3D frameworks from biomolecules as highly efficient trifunctional catalysts
Zailai Xie, Fuzhou University

No. 53:
Catalytic intermolecular dicarbofunctionalization of styrenes with CO2 and radical precursors
Veera Reddy Yatham, Institute of Chemical Research of Catalonia

No. 54:
Optimizing optical absorption, exciton dissociation, and charge transfer of a polymeric carbon nitride with ultrahigh solar hydrogen production activity
Guigang Zhang, Max Planck Institute of Colloids and Interfaces

No. 55:
Visible light driven Diels–Alder reactions on carbon nitride with dioxygen as sustainable mediator for photoinduced electrons
Yubao Zhao, Max Planck Institute of Colloids and Interfaces

No. 56:
Modified carbon nitrides with tunable band structures and their applications in organic synthesis
Meifang Zheng, Fuzhou University

No. 57
Photophysical characterization of ruthenium(II)-copper(II) systems for the photocatalytic oxygenation of organic substrates
Angélica Moreno Betancourt, Université Grenoble Alpes