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.
