ChemistryKoenig

“On-water” photosensitization enables redox neutral acylation and alkylation of quinones - Nature Communications Water-oil interfaces exhibit high cohesive energy density and form a supramolecular hydrogen-bonding network, which supports organic reactions in various ways. Here, the authors introduce the redox-ne...

'On Water' hydrogen bonding stabilizes the photo-excited state of quinones: application of Franck-Condon principle in organic synthesis. Congrats to all! #ChemSky #photocatalysis

doi.org/10.1038/s414...
“On-water” photosensitization enables redox neutral acylation and alkylation of quinones

We broadened the scope of 4-isoxazolines and oxa-aza-BCHeps in a highly regioselective fashion by photocontrol over strain and topology. A template for designing next-generation therapeutics and agrochemicals! Congrats to the team!

doi.org/10.26434/che...

We thank B. List and L. Alama for highlighting our collaboration pubs.acs.org/doi/10.1021/... in Synfacts!
#ChemSky #photocatalysis

Synthesis of α-Amino Acids via ConPET-Driven Amide Activation doi.org/10.1055/a-27...

Predictive, Data‐Driven Design of Red‐Light Photoredox Catalysts for C─Heteroatom Bond Formation From redox numbers to red light: Donor oxidation and core reduction potentials predict E0-0 in cyanoarene dyes, guiding selection of an efficient red-light catalyst, 4MeODPATPN (PC13). Under 620 nm l...

From donor/core CV to catalyst design:
a new method to develop inexpensive and tunable organic RL/NIR photocatalysts.
Dual Ni/photoredox C–heteroatom coupling with a new cyanoarene photocatalyst under 620 nm LEDs!
@angewandtechemie.bsky.social #Chemsky #photocatalysis
doi.org/10.1002/anie...

Room-Temperature Copper Cross-Coupling Reactions of Anilines with Aryl Bromides We present a novel copper-catalyzed method for aniline cross-couplings promoted by a 6-hydroxy picolinhydrazide ligand. The method achieves room-temperature reactivity with aryl bromides, enabled by a methanol/ethanol solvent mixture and a mild, functional group-compatible base, with catalyst loadings as low as 0.5 mol %. The use of industrially preferred solvents and base, as well as the high catalytic activity, offers a significant advancement in the practicality and scalability of industrial processes. Furthermore, the approach extends to the cross-coupling of aryl chlorides under elevated temperatures and demonstrates compatibility with additional nucleophile classes.

We used industrially preferred solvents, base, and low catalyst loadings to offer a significant advancement in the practicality and scalability of industrial processes.
Another collaboration with Bayer!
pubs.acs.org/doi/10.1021/...

Data Science-Assisted Workflow for Reaction Optimization in Process Chemistry We present a newly developed, data-assisted workflow at Bayer that integrates Bayesian optimization (BO) with CIME4R, an open-source data visualization tool with explainable AI features, to facilitate...

Improving transparency and user trust in machine-learning-guided reactions we combined Bayesian optimization (BO) with the CIME4R data visualization tool for the rapid identification of high-yielding conditions - only 0.5% of the full parameter space! Great collaboration!
doi.org/10.1021/acs....

Flavin-Photocatalyzed Benzylic Functionalization, Spirocyclization, and Spiroepoxidation of Phenols para-Quinone methides (p-QMs) are versatile, transient electrophilic dearomatized intermediates in organic synthesis, enabling a range of transformations, such as cycloadditions, nucleophilic addition...

Photogenerated para-Quinone methides undergo efficient transformations. Nice collaboration! #metal-free #photocatalysis #Chemsky
Flavin-Photocatalyzed Benzylic Functionalization, Spirocyclization, and Spiroepoxidation of Phenols @pubs.acs.org pubs.acs.org/doi/10.1021/...

Photoexcited Manganese Complex of Abnormal N-Heterocyclic Carbene in Molecular Hydrogen Activation via Hydrogen Atom Transfer Pathway In this work, we show that the innate reactivity of the photoexcited state of a Mn-hydride complex can be harnessed to design the activation of the H2 molecule for catalytic applications. Such activation of molecular hydrogen by a photoexcited heavier 5d metal (Ir) complex has recently been achieved; however, it has been realized with an earth-abundant and lighter 3d metal complex. Here, we demonstrate that an in situ-generated Mn–H complex of an abnormal N-heterocyclic carbene can activate molecular hydrogen upon photoexcitation. The key to this approach lies in the fact that ground-state manganese hydride absorbs light to undergo homolytic cleavage, generating a metalloradical (Mn·) and a hydrogen atom. This, in turn, enables the formation of an O–H bond upon reaction with an aldehyde. Simultaneously, the generated Mn· can activate the H2 molecule, reproducing the Mn–H species in its ground state along with a hydrogen atom. The trapping of important intermediates, such as Mn· species and associated radical intermediates, using spectroscopic techniques confirms the mechanistic proposal involving the excited state of the Mn complex.

News from Manganese! Congratulations to Rohan who published with his former group @pubs.acs.org
Photoexcited Manganese Complex of Abnormal N-Heterocyclic Carbene in Molecular Hydrogen Activation via Hydrogen Atom Transfer Pathway #ChemSky
pubs.acs.org/doi/10.1021/...

Harnessing Photochemistry in Natural Product Synthesis: From Strategy to Applications Photochemistry and total synthesis are deeply rooted in the history of organic chemistry, each developing independently while also intersecting frequently. Indeed, mild reaction conditions, versatility of transformations, and complementary selectivities to thermal methods make photochemistry an especially powerful tool for the synthesis of complex target molecules. In this Review, we highlight recent examples of total syntheses (from 2020 to 2025) featuring photochemical reactions as pivotal steps. Although the application of photochemistry in total synthesis has been consistently reviewed throughout the past decades, we feel that the wider emergence of photocatalytic methods, together with the continued importance of certain direct irradiation approaches, warrants its own discussion. We hope that our analytical approach and strategic insights will help us to identify cases where photochemical reactions could prove useful, thereby further encouraging their use in total syntheses.

The vast method development uses photochemistry as a guiding light through many steps in the synthesis of complex target molecules. General concepts with recent examples on the use of photochemistry in natural product synthesis are discussed. Thanks to Elina!
#ChemSky

pubs.acs.org/doi/10.1021/...

There are no words to express our sadness!
Our colleague and friend Armaz Tsutskiridze passed away
We all miss his smile, enthusiasm, politeness and expertise.
Our deepest condolences to his family!

Synthesis of α-Amino Acids by ConPET-Mediated CO2 Fixation into Amides Herein, we report a photocatalytic method for the selective functionalization of α-C(sp3)-H bonds adjacent to the nitrogen atom in amides. By harnessing a synergistic combination of hydrogen atom transfer (HAT), consecutive photoinduced electron transfer (ConPET), and reductive radical-polar crossover, we efficiently incorporated high-value electrophiles, including CO2, 13CO2, and deuterium, at the α-N position. The transformation proceeds in moderate to high yields across a diverse range of amides, representing a significant advancement in both isotopically labeled α-amino acid synthesis and amide deuteration.

We enable direct access to α-amino acids and deuterated amides with our metal-free photoredox-catalyzed strategy for carboxylation and deuteration @pubs.acs.org Nice collaboration with the Paixão group!
#ChemSky #photocatalysis #metal-free
pubs.acs.org/doi/10.1021/...

Photoredox/Nickel Dual Catalytic C(sp2)S Cross‐coupling of Bromoanilines Enabled by Mineral Acids Mineral acids promote nickel-catalyzed C(sp2)<span class='icomoon'></span>S cross-coupling of bromoanilines and related amine-containing electrophiles with thiols by protonating free amines, thereby facilitating oxidative addit...

Cross-coupling of unprotected bromoanilines with thiol nucleophiles: the acidic environment suppresses the formation of polythiolates, increasing the active nickel species and minimizing inner filter effects during #photocatalysis #ChemSky
@indrajitghosh85.bsky.social
doi.org/10.1002/adsc...

Fully Sensitized Upconversion Nanoparticles as Efficient Catalysts for NIR‐Driven UV Photochemistry Engineered NaYbF4:Tm3+@NaYF4 nanoparticles, featuring a fully sensitized Yb3+ lattice and an optimized core–shell architecture, convert five 980 nm photons by sequential absorption into a single 345 ...

How to engineer and use nanoparticles to enable energy-demanding [2 + 2] photocycloadditions under mild, near-infrared (NIR) excitation. A great potential in synthetic and biomedical applications! @angewandtechemie.bsky.social
#photocatalysis #nanoparticles #ChemSky
doi.org/10.1002/anie...

Photoswitches beyond azobenzene: a beginner’s guide Beilstein Journal of Organic Chemistry

Learn more about photoswitches!
This review describes the synthesis, structure–property relationships, and examples of applications for seven important classes of photoswitches
doi.org/10.3762/bjoc...

Generalizing Vinyl Halide Cross‐Coupling Reactions with Photoredox and Photoredox/Nickel Dual Catalysis A general strategy has been developed for predictable and robust vinyl halide cross-coupling reactions. This approach demonstrates broad applicability across seven distinct bond-forming transformatio...

Interested in vinyl halide chemistry?
Then use our new strategy to simplify your reactions!
Thanks to all involved!
@angewandtechemie.bsky.social
@indrajitghosh85.bsky.social
#ChemSky #photocatalysis #Nickel

doi.org/10.1002/anie...

Photo-Catalyzed Synthesis of Indanones from Aromatic Aldehydes and Terminal Alkynes Indanones are key structural motifs in pharmaceuticals and bioactive natural products, making their efficient synthesis a subject of continued interest. Conventional methods typically rely on transiti...

🔬 Our recent work on the direct synthesis of functionalized indanones from simple aromatic aldehydes and terminal alkynes has now been published in The Journal of Organic Chemistry. @chemistrykoenig.bsky.social
pubs.acs.org/doi/10.1021/...

Mechanistic Study of the Light‐Initiated Generation of Free Diazoalkanes: Towards Photo‐Orthogonal Synthesis A combined computational and experimental study elucidates the mechanism of the light-induced formation of free diazoalkanes in detail. Starting from deprotonated tosylhydrazone as the light-harvesti...

doi.org/10.1002/ceur...

Expanding the Repertoire of Photoswitchable Unnatural Amino Acids for Enzyme Engineering Enzyme engineering with photoswitchable unnatural amino acids (psUAAs) has a high potential for applications such as biocatalysis. Here, we extend the current repertoire of psUAAs to include more ver...

Engineering of light-sensitivity in enzymes holds significant promise for diverse applications in #biotherapy and #biocatalysis. Please see our collaboration in @angewandtechemie.bsky.social #ChemSky
Congrats to Caroline and Michela!
doi.org/10.1002/anie...

Mechanistic Study of the Light-Initiated Generation of Free Diazoalkanes: Towards Photo-Orthogonal Synthesis
Please see the prospects for photo-orthogonal synthesis by increasing the conc. in the photostationary state and the lifetime of nonstabilized diazo compounds for stepwise reactions #ChemSky

Alternative Mechanism of Enzymatic Photocontrol by Azobenzene Azobenzene is a widely recognized tool for achieving artificial spatiotemporal control of enzyme activity through the use of light. Photocontrol reversibility is typically based on photostationary sta...

An unexplored avenue for azobenzene #photoswitching with simultaneous irradiation at 365:420 nm!
Congrats to Ranit, Alba and especially Caroline! @pubs.acs.org #ChemSky
Alternative Mechanism of Enzymatic Photocontrol by Azobenzene | ACS Catalysis pubs.acs.org/doi/10.1021/...

Magnetic Stirring May Cause Irreproducible Results in Chemical Reactions Magnetic stirrers, the most widely used and ubiquitous devices for performing chemical reactions in laboratory settings, may cause reproducibility problems. Reproducibility in a range of chemical proc...

Shedding light on an overlooked significant facet:
Magnetic stirrers - used daily in millions of labs - may silently sabotage reproducibility!
pubs.acs.org/doi/10.1021/...

Green‐light Cerium Photocatalysis enabled by Pyridine N‐oxide Ligands Abstract: We report pyridine N-oxides as neutral ligands in cerium photocatalysis. By using those neutral ligands, photoactive Ce(IV)-species are generated, that show an extensive bathochromic shift ...

The effective utilization of green light in the CH-hydrazination of small molecules under very mild photocatalytic conditions.
Congrats to Nico! #ChemSky #photocatalysis
doi.org/10.1002/ejoc...

Reactivity of Superbasic Carbanions Generated via Reductive Radical‐Polar Crossover in the Context of Photoredox Catalysis Photocatalytic reactions with a reductive radical-polar crossover (RRPCO) involve intermediates with carbanionic reactivity. These are best described as free carbanions. Reactions with such carbanion...

Proud of Sascha that his collaboration is a most read article published from our University #openaccess #ChemSky #photocatalysis
doi.org/10.1002/anie...

Anthraquinone Sulfonates as Water‐Soluble Photocatalysts: Synthetic Applications and Perspectives The development of photochemistry in water is rapidly advancing, and the demand for water-soluble photocatalysts is increasing. Accordingly, anthraquinone sulfonates are interesting options for the a...

We are excited to present our perspective. We hope our work will inspire researchers for advancing the field of photocatalysis in water and prioritize the use of greener reaction conditions @chemistryeurope.bsky.social #photocatalysis #Chemsky
Congrats to Daniel and Andrey!

doi.org/10.1002/cptc...

Preassembly‐Controlled Radical Recombination at Bismuth: Decarboxylative C─N Coupling with Sulfonamides Radical processes involving bismuth hold great potential, but innovative strategies are required to control the reactivity of bismuth intermediates. Herein, we report a direct photochemical decarboxy...

We expanded our Bismuth LMCT methodology towards the direct decarboxylative C-N coupling of carboxylic acids with sulfonamides - great work by Elina and Dominik now out in #Chem.Eur.J. #ChemSky 🧪
doi.org/10.1002/chem...

Merocyanine-based photoacids as recyclable catalysts in visible-light-driven transformations Visible light-driven proton transfer is crucial in nature and catalysis. Here, we report that protic merocyanine-based photoswitches act as efficient and recyclable homogeneous Brønsted acid catalysts...

Have a look at our photoacid system tailored for small-molecule organocatalysis! Photo-promoted proton release efficiently enables Friedel–Crafts alkylation. Congrats to Armaz, Dana and @indrajitghosh85.bsky.social @chemcomm.rsc.org 🧪 #Chemsky #photocatalysis

doi.org/10.1039/D5CC...

Photocatalytic Dehydroformylation of Benzyl Alcohols to Arenes The combination of photoinduced hydrogen atom transfer (HAT) and cobalt catalysis gives access to a mild dehydroformylation sequence for the defunctionalization of benzyl alcohols to arenes. The tran...

A Top Cited Article in ChemPhotoChem!
Congrats to all involved! onlinelibrary.wiley.com/doi/full/10.... #TopCitedArticle @wiley.com

Was ist "Chemische Photokatalyse"? Und warum kann man mit Licht Medikamente herstellen?
Für alle, die Chemie unterrichten:
Die aktuelle Ausgabe von Naturwissenschaften im Unterricht Chemie März 2025, Heft 206, 9-13
www.friedrich-verlag.de/friedrich-pl...
#chemsky #photocatalysis

A step-by-step protocol of the synthesis of ethyl 4-((3-ethoxy-3-oxopropyl)thio)benzoate, building on the AD-Hoc principle we reported in Nature.
Congratulations to Florence and Indra
@indrajitghosh85.bsky.social
Thanks to the Dixon Group!
#photocatalysis #ChemSky 🧪
www.orgsyn.org/demo.aspx?pr...

Visible‐Light Photoredox Catalytic Direct N‐(Het)Arylation of Lactams Lactam rings can be introduced to a diverse range of arenes and heteroarenes employing our mild and efficient photoredox method. The N-(het)arylation of lactams also works in aqueous media, allowing ...

Our collaboration with the Benaglia group is effective in aqueous media, facilitating the functionalization of biomolecules. The photochemical reaction is scalable under continuous flow conditions, making it suitable for large-scale applications.
#ChemSky #photocatalysis
doi.org/10.1002/chem...