Light-enabled intramolecular [2 + 2] cycloaddition via photoactivation of simple alkenylboronic esters

• Lewis McGhie,
• Hannah M. Kortman,
• Jenna Rumpf,
• Peter H. Seeberger and
• John J. Molloy

Beilstein J. Org. Chem. 2025, 21, 854–863, doi:10.3762/bjoc.21.69

• , and control reactions support sensitization, enabling an intramolecular [2 + 2] cycloaddition to be realized accessing 3D bicyclic fragments containing a boron handle. Keywords: boron; catalysis; [2 + 2] cycloaddition; energy transfer; photochemistry; Introduction The strategic use of a photon to

Substituent effects in N-acetylated phenylazopyrazole photoswitches

• Radek Tovtik,
• Dennis Marzin,
• Pia Weigel,
• Stefano Crespi and
• Nadja A. Simeth

Beilstein J. Org. Chem. 2025, 21, 830–838, doi:10.3762/bjoc.21.66

• structural modifications affect the synthesis, photochemical, and thermal behavior of PAP derivatives introducing NAc-PAPs as novel compound set with enhanced photochemical performance. Our findings provide valuable guidance for designing functional PAPs with tailor-made photochemistry and photophysical

Synthesis and photoinduced switching properties of C₇-heteroatom containing push–pull norbornadiene derivatives

• Daniel Krappmann and
• Andreas Hirsch

Beilstein J. Org. Chem. 2025, 21, 807–816, doi:10.3762/bjoc.21.64

• catalytic back-conversion studies. Keywords: heterocycles; molecular solar thermal systems; norbornadiene; photochemistry; quadricyclane; Introduction In recent decades, the demand for renewable energy has increased tremendously [1]. A promising alternative to fossil fuels is the utilization of so-called

Photocatalyzed elaboration of antibody-based bioconjugates

• Marine Le Stum,
• Eugénie Romero and
• Gary A. Molander

Beilstein J. Org. Chem. 2025, 21, 616–629, doi:10.3762/bjoc.21.49

• ; bioorthogonality; chemoselectivity; late-stage functionalization; photochemistry; Introduction Antibodies represent increasingly important tools in several groundbreaking approaches to medical innovation, including basic biomedical research and therapy. One of the most critical requirements for the application of

• perhaps of no surprise that the recent renaissance of synthetic chemistry based on novel photochemical methods has been applied to their functionalization [30]. In the context of photochemistry applied to bioconjugation, photochemical affinity labelling (PAL) is a technique that has been used to create

• photochemistry continues to evolve, these strategies may pave the way for the creation of more homogeneous and optimized ADCs, enhancing their therapeutic outcomes and minimizing off-target effects. This perspective highlights the exciting future of photoredox methods in the development of next-generation ADCs

Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

• Long K. San,
• Sebastian Balser,
• Brian J. Reeves,
• Tyler T. Clikeman,
• Yu-Sheng Chen,
• Steven H. Strauss and
• Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

• ; perfluorobenzylation; photochemistry; Introduction The revolution of small organic molecules in the semiconductor industry continues to progress, replacing some silicon and metal-based electronic components. Acenes, such as anthracene (ANTH) and its higher homologues, represent some of the most studied materials that

Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• conventions. Although these dyes have been known since 1978, their photochemistry has only been briefly explored. In this work, during the synthesis of a series of these dyes (Figure 2a), we observed an unprecedented intermolecular [2 + 2] cycloaddition of syn-(ethoxycarbonyl,chloro)bimane (Cl2B), seen in

Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions

• Francesco Mele,
• Ana M. Constantin,
• Andrea Porcheddu,
• Raimondo Maggi,
• Giovanni Maestri,
• Nicola Della Ca’ and
• Luca Capaldo

Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33

• transformation from a conceptual standpoint. Another fundamental law in photochemistry is the Beer–Lambert law, which describes a negative exponential correlation between the transmittance of a solution containing chromophores (i.e., a light-absorbing species) and the optical path length (Figure 1). In essence

• the synthesis of novel compounds and materials. While the mechanisms underlying mechanochemical reactions are still under investigation [47][48][49][50], the increasing body of research demonstrates the potential of this technique to revolutionize synthetic chemistry. Combining photochemistry with

• light energy and mechanical forces have been integrated through the years, either in a combined or sequential manner. Our goal is not to provide an exhaustive review on photomechanochemistry [34][42][55], nor a detailed explanation of solid-state photochemistry [56][57], but rather to capture a snapshot

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• chemistry with significant potential in synthetic and biomedical fields. Keywords: green chemistry; medicinal chemistry; organic photochemistry; photocatalysis; red-light mediated transformations; Introduction Red-light-activated photocatalysis has recently gained significant interest as a tool for

• to narrow both absorption and emission peaks, along with a bathochromic shift in their spectra. Heptamethin cyanins, in particular, are highly relevant for NIR applications, making them valuable in photochemistry. Additionally, their solubilities, redox and photophysical properties can be fine-tuned

Recent advances in organocatalytic atroposelective reactions

• Henrich Szabados and
• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

• 219oa (84%, 92% ee). The unique combination of photochemistry and Brønsted acid-catalysis by CPA (R)-C23 was utilized in the cyclization reaction of cinnamates 220 forming N-arylquinolones 221 (Scheme 65) [95]. Optimized reaction conditions led to the formation of products 221 in remarkable yields with

Emerging trends in the optimization of organic synthesis through high-throughput tools and machine learning

• Pablo Quijano Velasco,
• Kedar Hippalgaonkar and
• Balamurugan Ramalingam

Beilstein J. Org. Chem. 2025, 21, 10–38, doi:10.3762/bjoc.21.3

• 16 microreactors capable of executing diverse conditions in parallel, including photochemistry. The temperature of the capillary reactors can be controlled independently, providing flexibility in experimentation. The reservoir-type distributor, featuring a baffle structure, not only ensures uniform

Giese-type alkylation of dehydroalanine derivatives via silane-mediated alkyl bromide activation

• Perry van der Heide,
• Michele Retini,
• Fabiola Fanini,
• Giovanni Piersanti,
• Francesco Secci,
• Daniele Mazzarella,
• Timothy Noël and
• Alberto Luridiana

Beilstein J. Org. Chem. 2024, 20, 3274–3280, doi:10.3762/bjoc.20.271

• photochemistry has introduced new ways of generating radicals like photoredox catalysis and via electron donor–acceptor (EDA) complexes [10][11][12][13]. These advances, coupled with modern electrochemical methods, chemical reactor engineering and light emitting diodes (LED), have eliminated the need for thermal

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• photochemistry, porphyrins are mainly used for the generation of singlet oxygen (1O2) or other reactive oxygen species. Porphyrins in the triplet excited state can relax to the ground state by transferring energy to molecular oxygen (triplet state) forming 1O2 (Figure 13b) [67]. Photosensitized singlet oxygen

• (1O2) finds many applications in photochemistry and photobiology, e.g., for wastewater treatment, fine chemical synthesis, and photodynamic therapy (PDT) [79][80][81][82][83]. Additionally, after light excitation, porphyrins can also oxidize a substrate by accepting electrons from a substrate molecule

Extension of the π-system of monoaryl-substituted norbornadienes with acetylene bridges: influence on the photochemical conversion and storage of light energy

• Robin Schulte,
• Dustin Schade,
• Thomas Paululat,
• Till J. B. Zähringer,
• Christoph Kerzig and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 3061–3068, doi:10.3762/bjoc.20.254

• up to 8 h at room temperature. Furthermore, the norbornadienes were transformed quantitatively into their quadricyclane photoproducts by irradiation with green light (520 nm) in the presence of a photosensitizer. Keywords: light energy conversion; photochemistry; photochromism; quadricyclanes

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• [3]. Transition-metal-catalyzed LSF strategies have been well-established over the past decades. More recently, with the vigorous development of photochemistry and electrochemistry, numerous innovative reports on LSF using photo-, electro-, and photoelectrochemistry have emerged. These areas have

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• screening and rapid optimization [46][47]. Homogenous heating and mixing in flow reactors can lead to higher reaction rates and yields. In terms of photochemistry, continuous flow setups provide enhanced light irradiation as well [48][49]. These advantages make flow chemistry a powerful tool for chemical

A fiber-optic spectroscopic setup for isomerization quantum yield determination

• Anouk Volker,
• Jorn D. Steen and
• Stefano Crespi

Beilstein J. Org. Chem. 2024, 20, 1684–1692, doi:10.3762/bjoc.20.150

• actinometry, thus demonstrating the reliability of our setup. Keywords: isomerization; molecular photoswitches; photochemistry; photon flux; UV–vis spectroscopy; Introduction Photoswitches are molecules that can undergo a light-driven structural rearrangement to populate a metastable state of the initial

Electrophotochemical metal-catalyzed synthesis of alkylnitriles from simple aliphatic carboxylic acids

• Yukang Wang,
• Yan Yao and
• Niankai Fu

Beilstein J. Org. Chem. 2024, 20, 1497–1503, doi:10.3762/bjoc.20.133

• method, we conducted the reaction with ibuprofen on a 3.0 mmol scale and obtained product 3 in 78% isolated yield. More importantly, the extremely mild reaction conditions imparted by the combination of electrochemistry and photochemistry made accessible a broad range of products with functionalities

Transition-metal-catalyst-free electroreductive alkene hydroarylation with aryl halides under visible-light irradiation

• Kosuke Yamamoto,
• Kazuhisa Arita,
• Masami Kuriyama and
• Osamu Onomura

Beilstein J. Org. Chem. 2024, 20, 1327–1333, doi:10.3762/bjoc.20.116

• chemical reagents; however, these methods have some drawbacks, such as reagent toxicity/stability and limited substrate scope [12][13][14]. While recent advances in photochemistry have remarkably expanded the synthetic utility of (hetero)aryl radicals in organic synthesis [15][16][17][18][19][20], visible

• . Recently, the groups of Lin and Lambert [48] and Wickens [49] independently demonstrated that aryl chlorides with highly negative reduction potentials engaged in C–X (X = P, Sn, B) and C–C bond formation reactions involving aryl radical species by integrating photochemistry and electrochemistry [50][51][52

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

• Johannes Rocker,
• Till J. B. Zähringer,
• Matthias Schmitz,
• Till Opatz and
• Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

• triplet reactivity of the Aza-H photocatalyst through spectroscopic measurements. The careful characterization of the versatile Aza-H photochemistry might contribute to the development of a new class of photoactive catalysts that can compete with traditional metal complexes and well-known organic

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• Temperature screening.a Additive screening. Fine-tuning of the reaction conditions. Supporting Information Supporting Information File 68: General methods, photochemistry set-up, reaction optimization, experimental procedures and compounds characterization. Funding The authors thank the Ecole Polytechnique

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• advancements in photochemistry, TM catalysis, NHC catalysis, and electrochemistry to show the generality of these RAEs in diverse mechanistic paradigms. Their application as radical progenitors continues to broaden the scope of radical-mediated reactions, especially in complex molecular settings, where issues

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• of prospective applications of indigo photoswitches. Keywords: indigoid dyes; photochemistry; photophysics; photoswitching; E–Z isomerization; Review Historical milestones in the development of photochromic indigo derivatives 1954: first reported photochromic indigo derivative – N,N'-diacetylindigo

• the electron density on the N atom in the ground state due to the electronic effects of substituents facilitates charge transfer during excitation, which leads to a decrease in the energy of the transition and a bathochromic shift of the absorption band, and vice versa. Photochemistry of indigo

Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• utilized to perform both HAT and RLT. While many challenges remain for achieving general asymmetric induction in RLT catalysis, this advance represents an important step toward this aspirational goal with many lessons to build upon. Our group has recently leveraged iron photochemistry to build on these

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• solubility for RFBs [59]. Meanwhile, methyl viologen has been used as a sacrificial electron acceptor in photochemistry [27]. Therefore, viologen species could be used as redox mediators for linking water oxidation to carbon dioxide reduction by accepting electrons during water oxidation and donating them