Study of tribenzo[b,d,f]azepine as donor in D–A photocatalysts

• Katy Medrano-Uribe,
• Jorge Humbrías-Martín and
• Luca Dell’Amico

Beilstein J. Org. Chem. 2025, 21, 935–944, doi:10.3762/bjoc.21.76

• of D–A structures makes them the ideal structures to further understand the structure–property relationship of D–A molecules for optimizing their photocatalytic performance by simpler modification of the different D–A subunits. In particular, D–A structures featuring sulfur-based acceptors and

• demonstrate that these simple D–A structures exhibit promising photocatalytic properties, comparable to those of more complex D–A–D systems. Keywords: donor–acceptor system; photocatalyst design; photoredox catalysis; organic photocatalyst; Introduction In recent years, photocatalysis has emerged as a

• chemistry and photocatalysis is the carbazolyl dicyanobenzene (CDCB) family. Since the initial report on the synthesis and photoluminescence study of 4CzIPN (1, Figure 1a) [6], the scientific community has recognized its potential under photocatalytic manifolds. This interest is attributed to: i) its

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

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

• applied to ADCs [34][35][36], the discussion below focuses on photocatalytic approaches that have been used to date to elaborate antibodies, providing insight into those methods that aim to revolutionize approaches to cancer treatment and other medical applications via the use of synthetically

• summary of the limited photoredox approaches reported for antibodies. Finally, the potential benefits and cautionary details these chemical strategies possess for creating ADCs with well-defined DAR and enhanced selectivity are discussed. Photocatalytic modification of proteins Photoredox chemistry has

• opened new avenues for designing advanced biotherapeutics, including ADCs and targeted delivery systems. Photoinduced modification of antibodies Although the bioconjugation of proteins via photocatalytic pathways is well-documented, the application of this method to the functionalization of antibodies

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

• rearrangements. Most organic molecules are colorless and, in fact, do not absorb visible light: highly energetic UV irradiation is typically needed. A milder approach is offered by photocatalytic approaches. Here, a photocatalyst is added to the reaction mixture to convert light energy into chemical potential to

• photochemical and photocatalytic methods [59], while others have used "mechanophotocatalysis" or "mechanophotochemistry" for greater specificity. Discussion Experimental setups for photomechanochemistry As mentioned above, the goal of the present perspective article is to put the spotlight on the technological

• exposing fresh material to light. In 2016, König and co-workers exploited rod milling to develop a photomechanochemical approach for the riboflavin tetraacetate (RFTA)-catalyzed photocatalytic oxidation of alcohols to the corresponding carbonyl compounds upon irradiation with five LEDs (λ = 455 nm) [69

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

• irradiation apparatus, e.g., UV radiation sources. Secondly, from a synthetic perspective, a broader range of substrates and catalysts can be considered as in most cases, they are incapable of absorbing red light and, consequently, cannot initiate a photocatalytic transformation, thereby minimizing the risk

• or side reactivity in a scope of around 50 examples with yields ranging from 27 to 97 % compared to the use of blue-light (Scheme 3a) [20]. In this way, T. Rovis et al. have exploited their photocatalytic system on the functionalization of drug-like scaffolds with moderate to good yields (Scheme 3b

• demonstrated the broad applicability of this photocatalytic system. It has to be noted that zinc-based photocatalysts with phthalocyanin ligands are not limited to energy-transfer pathways involving singlet oxygen generation. A recent work by Yoshimitsu et al. has shown that zinc(II)-based porphyrin complexes

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

• photocatalytic reactions for water molecule cleavage to produce hydrogen. The mobile robot (Figure 2b) acted as a substitute of a human experimenter by executing tasks and linking eight separate experimental stations, including solid and liquid dispensing, sonication, several characterization equipments, and

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

• photocatalytic activation (Figure 1b) [17][18][19][20][21]. A photocatalytic HAT or SET generates the corresponding boryl, α-amino or silyl radical, which can abstract a halogen atom from alkyl halides to form the corresponding alkyl radical. However, the use of TTMS as a XAT reagent had already been established

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

• combining the organocatalytic and photocatalytic potential of porphyrin macrocycles [98]. In 2024, Gupta and colleagues expanded on the success of free base porphyrin macrocycles as photoredox catalysts by introducing meso-arylcorroles (types A3 and A2B) for C–H arylation and borylation reactions activated

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• photocatalytic system under visible light irradiation (443 nm) [56]. Peroxidation of β-ketoesters, cyanoacetic esters, and malonic esters 37 was performed using the TBAI/TBHP system (Scheme 15) [57]. The highest product yields in the TBAI-catalyzed peroxidation were achieved with malonic acid esters, in contrast

• . Photocatalytic oxidation of radical A with [IrIV(ppy)3] regenerates [IrIII(ppy)3] and completes the photoredox catalytic cycle. The Bronsted acid catalyzes the formation of the isochroman oxocarbenium ion B, which is then nucleophilically attacked by TBHP to produce the target peroxide 69. Heteroatom (N, O

Synthesis of benzo[f]quinazoline-1,3(2H,4H)-diones

• Ruben Manuel Figueira de Abreu,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2708–2719, doi:10.3762/bjoc.20.228

• other compounds with medicinal or photophysical properties [52][53][54][55]. Compounds A are related to the class of natural products known as coumestans, while B resembles flavins. While the medical potential of coumestans is still the subject of current research, interesting photocatalytic properties

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

• the authors to propose the following mechanism: The process begins with the anodic oxidation of Mn(II) coordinated with N3− to generate a Mn(III) species. In the photocatalytic cycle, the excitation of DDQ (2,3-dicyano-5,6-dichlorobenzoquinone) as hydrogen-atom-transfer (HAT) catalyst results in the

Visible-light-mediated flow protocol for Achmatowicz rearrangement

• Joachyutharayalu Oja,
• Sanjeev Kumar and
• Srihari Pabbaraja

Beilstein J. Org. Chem. 2024, 20, 2493–2499, doi:10.3762/bjoc.20.213

• OH). The Achmatowicz product is formed by addition of water to oxocarbenium intermediate A followed by elimination of L. Conclusion In conclusion, an integrated continuous PFR platform for photocatalytic functionalization of furfuryl alcohols to dihydropyranones through an Achmatowicz rearrangement

Photoredox-catalyzed intramolecular nucleophilic amidation of alkenes with β-lactams

• Valentina Giraldi,
• Giandomenico Magagnano,
• Daria Giacomini,
• Pier Giorgio Cozzi and
• Andrea Gualandi

Beilstein J. Org. Chem. 2024, 20, 2461–2468, doi:10.3762/bjoc.20.210

• intramolecular nucleophilic attack induced by photocatalytic oxidation was reported by Yoon et al. with tosylamide derivatives [29]. Specifically, amides were employed in a photoredox cyclization process using a strong photooxidative acridinium catalyst such as the Fukuzumi catalyst (I, Figure 1B) [30][31

• starting from succinimide (Scheme 3). Through a simple reaction in toluene at 80 °C in the presence of Zn(OAc)2, the hemiaminal derivative 13 underwent substitution with cinnamyl alcohol, resulting in the isolation of 14 with a satisfactory yield. Under optimized reaction conditions, the photocatalytic

Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis

• Stefan P. Schmid,
• Leon Schlosser,
• Frank Glorius and
• Kjell Jorner

Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

A facile three-component route to powerful 5-aryldeazaalloxazine photocatalysts

• Ivana Weisheitelová,
• Radek Cibulka,
• Marek Sikorski and
• Tetiana Pavlovska

Beilstein J. Org. Chem. 2024, 20, 1831–1838, doi:10.3762/bjoc.20.161

• , water), which has become a common method for the synthesis of these derivatives [3][22][25][30][31][32][33]. In our previous studies [14][15][16][17][18][19] we have shown that the 5-aryl and 7,8-substitutients of the pyrimido[4,5-b]quinoline core have a significant effect on the photocatalytic activity

Benzylic C(sp³)–H fluorination

• Alexander P. Atkins,
• Alice C. Dean and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

• fluoride. Manganese-catalysed benzylic C(sp3)–H fluorination with AgF and Et3N·3HF and proposed mechanism. 19F NMR yields in parentheses. Iridium-catalysed photocatalytic benzylic C(sp3)–H fluorination with nucleophilic fluoride and N-acyloxyphthalamide HAT reagent. Iridium-catalysed photocatalytic

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

• photocatalytic and electrochemical deoxygenation of acids and alcohols has attracted significant attention as the strategic cleavage of the C–O bond is quite challenging and opens up new possibilities for constructing useful compounds [12][13][14]. The use of photogenerated carbon-centered radicals, such as acyl

• targeted absorption wavelength, and the overall efficacy. Researchers continue to explore and design photocatalysts to enhance the performance in various photocatalytic applications. Visible-light-induced photoredox catalysis has been used in a variety of chemical reactions, including C–C, C–N, C–O, and C

• –halogen bond formation, as well as C–H functionalization [27]. Some notable examples include C–H arylation, various cross-coupling reactions, oxidative coupling, and photocatalytic radical reactions. The advantages of visible-light-induced photoredox catalysis are due to the ability to utilize visible

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

• photocatalyst (PC•+/PC = +1.12 V vs SCE) is then regenerated by an electron transfer from sodium p-toluenesulfinate (TsNa) (Ts•/Ts− = +0.70 V vs SCE) closing the photocatalytic cycle [45]. Unlike other prominent photocatalysts, little to nothing is known about the reactivity, the photophysical properties or the

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

• studies [45] a plausible photocatalytic cycle could be proposed (Scheme 5). Upon light irradiation, single-electron reduction of Ts-ABZ (3) (E1/2red = −0.62 V vs SCE) [45] by the excited state photocatalyst (E1/2 [RuIII/RuII*] = −0.86 V vs SCE) [53] can occur to form an azide radical, which upon addition

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

• Geng-Xin Liu,
• Xiao-Ting Jie,
• Ge-Jun Niu,
• Li-Sheng Yang,
• Xing-Lin Li,
• Jian Luo and
• Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

• chemoselectivity (1,2-/1,4-addition = 4:1). Diazo esters suitable for this transformation were examined next. The MCRs with diazo substrates equipped with different substitution patterns were accommodated under the mild photocatalytic conditions to generate the desired 1,4-addition products in moderate to good

• reactive under the photocatalytic conditions, providing the corresponding 1,2-adducts 6a, 6b, and 6c smoothly in 73%, 93% and 34% yields, respectively. Commercially available amines with a broad range of heterocyclic rings (e.g., morpholine, piperazine, pyrrolidine, homopiperazine) also readily

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

• Luan A. Martinho and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

• (insomnia). Some recent synthetic approaches to imidazo[1,2-a]pyridine scaffolds include synthetic pathways of transition metal-catalyzed reactions [14], cyclization [15], condensation [16], heteroannular [17], and photocatalytic reactions [18]. These approaches usually involve non-trivial reaction

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• proximity of the metallic centers which allows MMLCT transitions. These properties have been used to generate reactive oxygen species (ROS) and efficient photocatalytic oxidative cyanation of N-phenyl-1,2,3,4-tetrahydroisoquinoline. The photocatalytic activity of the catalyst could be allosterically imbibed

• bisalkynylplatinum(II)–terpyridine clips [54]. The dimer showed photocatalytic activity in the photooxidation of a secondary amine to the corresponding imine that could be deactivated and reactivated by opening or closing the tweezers. Variations on multidentate N-donor ligands have also been developed by Lehn and

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

• specific activation mechanism, both net reductive and redox neutral transformations can be implemented. Photocatalytic reductive quenching mechanism Among the most common reactions of NHPI esters are radical additions to electron-deficient olefins under net-reductive conditions, often referred to as Giese

• esters for the construction of quaternary carbons via conjugate addition of 3° radicals [39][40]. In general, this transformation operates under a reductive quenching photocatalytic cycle, requiring a stoichiometric reductant (Scheme 4A). Both TM complexes, and organic dyes such as eosin Y [41][42][43

• the chiral phosphate co-catalyst (Scheme 5B). This event leads to the generation of a potent IrII reductant that begins the photocatalytic cycle by reducing 16 into radical anion 17 while regenerating the ground state of the IrIII photocatalyst. After fragmentation, α-amino radical 18 was proposed to

Nucleophilic functionalization of thianthrenium salts under basic conditions

• Xinting Fan,
• Duo Zhang,
• Xiangchuan Xiu,
• Bin Xu,
• Yu Yuan,
• Feng Chen and
• Pan Gao

Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26

• ]. Recently, Ritter and co-workers reported that alkylthianthrenium salts can be employed to undergo reactions with N/O-nucleophiles under photocatalytic conditions [46]. Nevertheless, additional transition metal catalysts, visible light, or electrochemical devices are required for the reported works