Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

• Betty A. Kustiana,
• Galuh Widiyarti and
• Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

Recent advances in controllable/divergent synthesis

• Jilei Cao,
• Leiyang Bai and
• Xuefeng Jiang

Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73

• via a proton transfer promoted by diisopropylethylamine. In 2023, the Jiang research group achieved a chemically divergent photocatalytic asymmetric synthesis using a dual catalytic system consisting of a chiral phosphoric acid and dicyanopyrazine (DPZ) as the photosensitizer (Scheme 20) [49]. By

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

• used to achieve higher yields [27]. Even in the absence of a transition-metal-based photosensitizer, a recent study showed that perfluoroalkylation using perfluoroalkyl iodides (RFI) could be carried out by activation of the RF–I bonds by formation of electron donor–electron acceptor complexes with an

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

• irradiation. The authors claim that toluene acts as a photosensitizer since cyclohexane, which has similar solubilizing power, did not serve well as a LAG agent. The authors demonstrated that nanographenes could be obtained via cyclodehydrochlorination of 10.3 under photomechanochemical conditions as well

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

• annihilation upconversion. This system achieves red-to-blue upconversion under red-light irradiation, rivaling the performance of traditional heavy-metal systems such as Os(II) complexes. By employing a Cr(0) photosensitizer combined with a silylacetylene-decorated anthracene annihilator, the authors have

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

• supramolecular systems. This section covers advancements in the field of metal-free macrocyclic photocatalysis, with a focus on porphyrin macrocycles, since calix[4]pyrroles do not act as photosensitizer. As the field of metal-free porphyrins as photoredox catalysts is still in its early stages, there are only a

• and a photosensitizer, facilitating photoinduced electron transfer (PET) to form the active cation radical B, and intersystem crossing (ISC) for energy transfer to generate the triplet carbene C. Radical B then reacted with biradical C, producing the new radical D, which accepted an electron from the

• suggested that the reaction of the porphyrin catalyst with the enamine and ethyl diazoacetate (EDA) played a crucial role in these α-alkylation reactions. This work demonstrated a dual catalytic system where porphyrin functioned as both a photoredox catalyst and a photosensitizer. Later, the same group used

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

• be investigated in the presence of the photosensitizer because these substrates have no sufficient solubility in acetonitrile. To assess the efficiency of the photoreactions, photoisomerization quantum yields were determined in cyclohexane by actinometry (λex = 310 nm or 340 nm) [41][42]. The quantum

• amounts of unidentified by-products formed. Nevertheless, it was shown exemplarily that the photoisomerization can be performed under milder conditions and upon excitation with visible light in the presence of [Ru(phen)3](PF6)2 as a photosensitizer. Under these conditions, the derivatives 1i and 1l were

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• photosensitizer and DIPEA was effective as a base (Scheme 12). The reaction yielded the E-isomers in a solvent mixture of methanol/water 5:1 under blue LED light (467 nm) irradiation in good yields. Various DAIRs substituted at different positions were found to be suitable for the reaction giving the respective

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• -butyl arenes were generated. This underpinned the formation of sec-butyl radicals in the system that rapidly reacted with O-benzyl xanthates before participating in the nickel-catalyzed cross-coupling reactions. Precatalyst [Ni(dtbbpy)(H2O)4]Cl2 (50) and photosensitizer [Ir(dF(CF3)ppy)2(bpy)]PF6 (49

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

• determine the ISC quantum yield, ΦISC, using the well-studied photosensitizer [Ru(bpy)3]Cl2 (Rubpy) as reference for actinometry [78][79][80]. This approach involved employing identical excitation conditions at 355 nm (Figure 4A) and monitoring the GSB of Rubpy with a literature-reported difference

Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• example, as a photosensitizer in photodynamic therapy. Keywords: biomaterial; fullerene; peptide; water-soluble; Introduction Since the seminal discovery in 1985 by Kroto, Smalley, Curl, and co-workers [1], fullerenes, specifically buckminsterfullerene C60, have intrigued the scientific community. The

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

• photosensitizer in an energy-transfer (EnT) mechanism. This proposal was supported by fluorescence quenching measurements, as well as the direct excitation of 44 by UV irradiation, resulting in the formation of 45 in a 45% yield. According to this hypothesis, NHPI ester 44 would adopt a favorable conformation (46

Tandem Hock and Friedel–Crafts reactions allowing an expedient synthesis of a cyclolignan-type scaffold

• Viktoria A. Ikonnikova,
• Cristina Cheibas,
• Oscar Gayraud,
• Alexandra E. Bosnidou,
• Nicolas Casaretto,
• Gilles Frison and
• Bastien Nay

Beilstein J. Org. Chem. 2024, 20, 162–169, doi:10.3762/bjoc.20.15

• ]. Results and Discussion To test the feasibility of this reaction sequence, the aromatic substrate 1 readily accessible by the prenylation of commercial diethyl benzylmalonate [21] was first used. The photooxygenation of 1 was performed in CH2Cl2 in the presence of methylene blue (MB) as a photosensitizer

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• ; heterocycles; photocyclization; photosensitizer; styrylpyridines; Introduction DNA intercalators – most often represented by small planar heteroaromatic compounds – play an important role as chemotherapeutic agents [1][2][3][4]. Specifically, upon intercalation into the DNA double helix such ligands can cause

• cancer [39], and bacterial, fungal, parasitic and viral infections [40][41]. In general, PDT operates on the basis of a photosensitizer, which generates reactive intermediates upon irradiation [42][43][44][45]. Hence, in the type-I mechanism the photosensitizer induces the formation of reactive oxygen

• species (ROS), such peroxyl, alkoxy and hydroxyl radicals, or carbon-centered radicals, which subsequently induce DNA strand cleavage. In the type-II mechanism, a triplet-excited photosensitizer reacts with molecular oxygen to give highly reactive singlet oxygen, 1O2, as reactive intermediate, which in

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• Supporting Information File 1). We speculate that this degradation is due to the reaction with singlet oxygen generated by the compound as a photosensitizer; indeed, we have recently shown [31] that IF-TTF compounds are reactive towards singlet oxygen at the central fulvene bond but, in contrast, IF-TTFs

Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• adapted with permission of Institution of Chemical Engineers (IChemE) and The Royal Society of Chemistry from [38] (“Cationic and radical polymerization using a boron–thienothiophene–triphenylamine based D-π-A type photosensitizer under white LED irradiation”) by A. Suerkan et al., Mol. Syst. Des. Eng

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• purpose, three main components are needed: a photosensitizer (PS), which acts like a light-antennae harvesting system in natural photosynthesis, a catalyst (Cat.), reacting directly with CO2 after being reduced, and a sacrificial electron donor (SeD). When the involved (photo)catalysts are homogeneous

• developing the major components of a photocatalytic system for CO2 reduction, such as the photosensitizer (PS), the catalyst, and the sacrificial electron donor (SeD). Nevertheless, the solvent and eventual additives play an important role too [6], as they can influence the (photo)redox properties of the

• complex [Cu(dmp)DPEPhos](BF4), well-investigated and used in several photocatalytic reactions [20][21][41], acting as a cost-effective benchmark photosensitizer. Herein, we present a study for the selectivity control of the novel Co(II) catalyst 1, aiming at maximizing the catalytic efficiency, and

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

• couple the reduction to water oxidation or other reactions. Furthermore, the performance of the molecular photosensitizer and catalyst combinations developed are often very dependent on the properties of the sacrificial donors. This review has two aims: 1. Highlight work being done to recycle sacrificial

• in systems for carbon dioxide reduction (see Figure 1). Reductive quenching of the photosensitizer occurs when the sacrificial donor reduces the photoexcited photosensitizer (reductive quenching pathway). Regeneration of photooxidized photosensitizers occurs when the excited dye is first oxidatively

• low absorption in the visible region to prevent side reactions and allow the photosensitizer to absorb as much light as possible. The oxidation potential of the sacrificial electron donor must be less positive than the reduction potential of the excited or oxidized photosensitizer for quenching or

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• different flexibility. The crown ether derivative acts as a chassis in order to fix the thread. A ferrocenyl group attached at one of the ends of the linear component serves as a photosensitizer allowing the absorption of visible light. The different substitution induced different types of deformations

• different materials [11]. Towards biocompatible applications [71], the use of visible light irradiation as input which leads to the desired function is a necessary requirement. In this scenario, the incorporation of photosensitizer motifs is a suitable strategy to allow such a performance. Towards this

• direction, one potential strategy is the approach followed by Feringa and co-workers [72], in which palladium-porphyrin photosensitizer-based struts were employed within a metal-organic material, allowing the use of green light as irradiation source because of the effective energy transfer between these

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• , Gutierrez and Molander reported the coupling 4-alkyl-1,4-dihydropyridines 31 with heterobicyclic alkenes 30 under photoredox/Ni dual catalysis (Scheme 6) [39]. In contrast to other photoredox-mediated transformations, the authors utilized the inexpensive organic photosensitizer 4-CzIPN (Scheme 6 and Scheme

• photoexcitation of the photosensitizer 43 to form 44 which can oxidize aniline 36a to give radical cation 46 (Scheme 7). Deprotonation by DBU produces the radical 40. The radical anion photosensitizer 45 can reduce Ni(I) to Ni(0), closing the first catalytic cycle. The Ni(0) complex can undergo oxidative addition

Combining the best of both worlds: radical-based divergent total synthesis

• Kyriaki Gennaiou,
• Antonios Kelesidis,
• Maria Kourgiantaki and
• Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

• . Interestingly, irradiation at 365 nm even in the presence of photosensitizer and O2 failed to furnish (+)-jungermatrobrunin A (89), and 90 was obtained as the sole product, albeit in low yield (14%). Attempts to optimize the yield always afforded recovered 88, hinting at a potential equilibrium between 88 and

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

• . Notably, the reaction did not proceed in the dark or in the absence of the photosensitizer at 30 °C; further, the reaction generated the desired product in lower yield at 120 °C. The scope was broad and tolerated a wide array of 1,3-keto esters and 1,3-diketones, as well as both benzylic and aliphatic C

Visible-light-mediated copper photocatalysis for organic syntheses

• Yajing Zhang,
• Qian Wang,
• Zongsheng Yan,
• Donglai Ma and
• Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

• product Nu–R can be obtained through an inner-sphere pathway between [LnCuIINu]X and the radical R• [41][42] (Scheme 5A). Alternatively, a photosensitizer generated a radical via reduction or oxidation, and is not engaged in the key bond construction. [LCuI] is photoexcited to generate LnCuI*, which

• form the desired product 13 (Scheme 9). In 2019, the same group [56] applied this protocol to the asymmetric cyanofluoroalkylation of alkenes. Under visible-light irradiation, the Cu-based catalyst plays a dual role as both the photosensitizer for the SET and the catalyst for asymmetric control (Scheme

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• -catalyzed C–H alkylation strategy to use the readily available inexpensive organo-photocatalyst benzaldehyde as the HAT photocatalyst under UVA irradiation [68][86]. Thus, the combination of NiBr2·glyme/dtbbpy, benzaldehyde as both the photosensitizer and hydrogen abstractor, and K2HPO4 as a base under

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138