Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• , their scope has recently expanded to include X–H insertions based on single electron transfer (SET) mechanisms, cycloadditions based on blue LED photochemistry and radiofluorinations of unactivated arene motifs. In these reports, mechanistic proposals commonly treat the hypervalent iodine atom as being

Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• flow using the HANU flow reactor, indicating scalability and improving safety. Keywords: catalyst-free; flow chemistry; oxygen; photochemistry; sustainable oxidation; Introduction Oxidation reactions are widely used in the chemical industry, but are often problematic due to challenges with

• [23][24] and methods for oxidation such as photochemistry, or electrochemistry have been developed [2][25]. However, low selectivity and the need for appropriate catalysts that are stable, cost-effective, and easy to remove remain problematic. Recently, catalyst-free procedures using O2 or air have

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• , or it is trapped with pyrrole derivatives 3 in a C–C bond formation to afford arylated products 4. Based on the ultrashort lifetime of *PDI•− (τ = 145 ps), the notion of its photochemistry has attracted skepticism and it has been suggested decomposition products of *PDI•− may instead serve as

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Mikhail E. Minyaev and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58

• important role in modern chemistry allowing to create novel original synthetic methods. UV-initiated reactions of heterocyclic systems are a significant part of organic photochemistry and there are numerous such transformations for various classes of heterocycles known in the literature [11][12][13][14][15

• results, we started the photochemistry study of the considered pyrimidines from the corresponding methylated derivatives of 9. The products 10 were obtained by alkylation of compounds 9 with methyl iodide in DMF in the presence of K2CO3 (Scheme 4). At first, the photochemical behavior was investigated for

Direct C2–H alkylation of indoles driven by the photochemical activity of halogen-bonded complexes

• Martina Mamone,
• Giuseppe Gentile,
• Jacopo Dosso,
• Maurizio Prato and
• Giacomo Filippini

Beilstein J. Org. Chem. 2023, 19, 575–581, doi:10.3762/bjoc.19.42

• ). Mechanistic investigations are reported. These studies provide convincing evidences for the photochemical formation of reactive open-shell species. Keywords: alkylation; EDA complex; halogens; indoles; photochemistry; Findings Direct replacement of carbon–hydrogen (C–H) bonds with new carbon–carbon (C–C

• on noble metal complexes has been constantly declined over recent years due to cost, availability, and toxicity, therefore discouraged by the modern guidelines towards implementation of sustainable chemical production schemes [6]. In the last decades, organic photochemistry has become a prominent

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• ; Introduction Porphyrins are an aromatic, immensely conjugated, and colorful macrocyclic array with remarkable optical, electrochemical, and biological features. It is one of the most fascinating heterocyclic molecules which have various applications in catalysis, materials sciences, photochemistry and

Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• acetone and water to a hemiacetal that can decompose to 11 (Scheme 4B) [43]. Furthermore, 1 shows an interesting photochemistry (Scheme 4C). A [2 + 2] cycloaddition of the endocyclic double bonds yields 12 whose formation is understandable from conformers 1c and 1d. The all-cis stereoisomer 14 requires a

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

• Blaine G. Fiss,
• Georgia Douglas,
• Michael Ferguson,
• Jorge Becerra,
• Jesus Valdez,
• Trong-On Do,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

• -PCN300) show a reduction in photoluminescent recombination, as well as a nearly two-time increase in photocurrent under broad spectrum irradiation, which are appealing properties for photocatalysis. Keywords: carbon nitride; density functional theory; mechanochemistry; phosphorus; photochemistry

• explored herein the use of solvent-free, room temperature mechanochemistry to access phosphorus-linked carbon nitride with repeating heptazine units, which were found to show improved photochemistry over pristine graphitic carbon nitride (g-CN). Additionally, the effect of a 1-hour annealing period at 300

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

• Wei-Hsin Hsu,
• Susanne Reischauer,
• Peter H. Seeberger,
• Bartholomäus Pieber and
• Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

• ; heterogeneous catalysis; metallaphotoredox catalysis; packed bed; photochemistry; Introduction The amount and impact of visible-light-mediated protocols in organic synthesis have increased dramatically since the late 2000s [1]. The main driving force of this phenomenon is the novel reactivity afforded by

• . Overall, the lack of catalyst separation and the possibility of combining the reactor with in-line analytical feedback enables the flow synthesis of C–S and C–O coupled products in a simple, versatile and amenable to automation way. Different approaches to heterogeneous photochemistry in flow. a) Serial

Synthesis, optical and electrochemical properties of (D–π)₂-type and (D–π)₂Ph-type fluorescent dyes

• Kosuke Takemura,
• Kazuki Ohira,
• Taiki Higashino,
• Keiichi Imato and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2022, 18, 1047–1054, doi:10.3762/bjoc.18.106

• practical concern with the objective of not only fundamental studies [1][2][3][4][5][6][7][8][9][10][11][12][13] in synthetic chemistry, electrochemistry and photochemistry, but also their potential applications to emitters for optoelectronic devices, such as organic light-emitting diodes (OLEDs) [14][15

A study of the photochemical behavior of terarylenes containing allomaltol and pyrazole fragments

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2022, 18, 588–596, doi:10.3762/bjoc.18.61

• established by X-ray diffraction. Keywords: allomaltol; ESIPT process; photochemistry; pyrazoles; terarylenes; Introduction The investigation of the photochemical behavior of organic products is a significant part of modern materials science and technology. The UV-induced processes are extensively employed

• bifunctional objects provides access to novel UV irradiation-based synthetic methods. Continuing our studies devoted to the photochemistry of terarylenes [27][28][29][30][31][32], in this communication we studied the UV-promoted reaction of pyrazole derivatives 12 containing a 3-hydroxypyran-4-one fragment

Borylated norbornadiene derivatives: Synthesis and application in Pd-catalyzed Suzuki–Miyaura coupling reactions

• Robin Schulte and
• Heiko Ihmels

Beilstein J. Org. Chem. 2022, 18, 368–373, doi:10.3762/bjoc.18.41

• quadricyclane upon irradiation, whereas the back reaction can be accomplished by thermal treatment. Keywords: molecular solar thermal system; Pd-mediated catalysis; photochemistry; photoswitches; quadricyclanes; Introduction Norbornadiene (1a, bicyclo[2.2.1]heptadiene) is a photochromic compound that has

Earth-abundant 3d transition metals on the rise in catalysis

• Nikolaos Kaplaneris and
• Lutz Ackermann

Beilstein J. Org. Chem. 2022, 18, 86–88, doi:10.3762/bjoc.18.8

• functionalization enabled the de novo assembly of bioactive molecules [9]. The full potential of the mild nature of C–H functionalization is unlocked by the merger with modern photochemistry and electrocatalysis manifolds. In this context, recent advances were realized by the combination of photoredox catalysis and

A photochemical C=C cleavage process: toward access to backbone N-formyl peptides

• Haopei Wang and
• Zachary T. Ball

Beilstein J. Org. Chem. 2021, 17, 2932–2938, doi:10.3762/bjoc.17.202

• -formyl amide products have unique properties and reactivity, but are difficult or impossible to access by traditional synthetic approaches. Keywords: formyl peptide; nitroaryl compound; nitroso compound; olefin cleavage; photocleavage; Findings The photochemistry of nitroaromatic functional groups has

• concept described here might be useful for the synthetic unmasking of relatively sensitive imido structures. For chemical biology applications, the results point to a far more diverse photochemistry than previously assumed for vinylogous photocleavage systems. Although formyl hydrolysis to the “expected

Polymer chemistry: fundamentals and applications

• Bernhard V. K. J. Schmidt

Beilstein J. Org. Chem. 2021, 17, 2922–2923, doi:10.3762/bjoc.17.200

• materials [6]. This thematic issue covers a broad range of current topics in polymer chemistry, from synthesis to materials and applications. In the area of synthetic methods, the use of click photochemistry in polymer and organic molecule synthesis is presented, as well as the combination of polymers with

Towards new NIR dyes for free radical photopolymerization processes

• Haifaa Mokbel,
• Guillaume Noirbent,
• Didier Gigmes,
• Frédéric Dumur and
• Jacques Lalevée

Beilstein J. Org. Chem. 2021, 17, 2067–2076, doi:10.3762/bjoc.17.133

• polymerization of acrylate/epoxy monomer blends) can also be carried out upon NIR light with the proposed systems. Keywords: cyanine; NIR light; photochemistry; Introduction Photopolymerization processes are well established due to the specific features and advantages. Indeed, the reaction is carried out at

Icilio Guareschi and his amazing “1897 reaction”

• Gian Cesare Tron,
• Alberto Minassi,
• Giovanni Sorba,
• Mara Fausone and
• Giovanni Appendino

Beilstein J. Org. Chem. 2021, 17, 1335–1351, doi:10.3762/bjoc.17.93

• Pharmacopoeia [60]. The last two decades of the Turin years (1900–1918) The first decade of the past century was a magic moment for science in general and for the Italian organic chemistry community in particular, with Ciamician and Paternò setting the foundation of organic photochemistry in what has been

• cogently named “the Bell’Epoque of photochemistry” [61]. Guareschi was, however, alien to the exciting developments of those years. The research on pyridines and, in general, his organic chemistry studies were gradually phased out due to a growing involvement in issues of national relevance that, in turn

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

• Zhonglie Yang,
• Yutong Liu,
• Kun Cao,
• Xiaobin Zhang,
• Hezhong Jiang and
• Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

• majority cases. Moreover, in line with the theme of green chemistry, light is the sole external energy source in EDA complex pathways. Except for the pioneering research on EDA complexes in the 20th century, there was not much progress in the follow-up. Until the past few years, EDA-complex photochemistry

• photochemistry, two kinds of EDA complexes were involved in this approach, explaining the reason why the yield increased significantly when morpholine was employed as an organic base additive, which was exploited in the screening stage of the reaction conditions. In 2019, Xia and colleagues [46] reported that

• yield of this reaction can reach 7.6 g ⋅ h−1 on a gram scale, indicating that the flow step is promising in photochemistry. In 2019, Aggarwal and colleagues [38] employed Katritzky salt 119 as electron acceptor and HE 79 as electron donor to form an EDA complex, providing the corresponding alkyl radical

Mesoionic tetrazolium-5-aminides: Synthesis, molecular and crystal structures, UV–vis spectra, and DFT calculations

• Vladislav A. Budevich,
• Sergei V. Voitekhovich,
• Alexander V. Zuraev,
• Vadim E. Matulis,
• Vitaly E. Matulis,
• Alexander S. Lyakhov,
• Ludmila S. Ivashkevich and
• Oleg A. Ivashkevich

Beilstein J. Org. Chem. 2021, 17, 385–395, doi:10.3762/bjoc.17.34

• tetrazoles [11][12]. The first representatives of tetrazole-5-aminides were reported in the 1950s [13][14], whereas next publications were appeared only five decades later, being devoted to the synthesis and photochemistry of 1,3-diaryltetrazolium-5-aminides [15][16][17][18][19][20][21]. NMR studies of a few

Metal-free synthesis of biarenes via photoextrusion in di(tri)aryl phosphates

• Hisham Qrareya,
• Lorenzo Meazza,
• Stefano Protti and
• Maurizio Fagnoni

Beilstein J. Org. Chem. 2020, 16, 3008–3014, doi:10.3762/bjoc.16.250

• . Keywords: aryl phosphates; biarenes; metal-free synthesis; photochemistry; photoextrusion; Introduction It is difficult to overestimate the importance of aromatics in drug development. Indeed, introducing an aromatic or a heteroaromatic ring, most often a (substituted) phenyl ring, into a biologically

• metal-free eco-sustainable conditions we reinvestigated the photochemistry of di- and triaryl phosphates III and IV (Scheme 1e), compounds that can be easily achieved from the corresponding phenols [62][63]. Results and Discussion At the onset of our investigation, we tested a triaryl phosphate such as

Dawn of a new era in industrial photochemistry: the scale-up of micro- and mesostructured photoreactors

• Emine Kayahan,
• Mathias Jacobs,
• Leen Braeken,
• Leen C.J. Thomassen,
• Simon Kuhn,
• Tom van Gerven and
• M. Enis Leblebici

Beilstein J. Org. Chem. 2020, 16, 2484–2504, doi:10.3762/bjoc.16.202

• . Photochemistry spans a number of reactions. For organic chemistry, 8000 photoreactions have been listed since 1975 [1]. Despite the huge portfolio, there is a lack of industrial applications of photochemistry. Van Gerven et al. listed five industrial applications of photochemistry in commercial wastewater

• has already been proven to be successful [4]. These examples show that photochemistry is a viable alternative to conventional chemistry approaches. In addition to specialty chemicals and wastewater treatment, photochemical pathways can also be used for methanol production [5], N2 fixation [6], and CO2

• sequestration [7]. Still, photochemistry has not been exploited much in industry since the distribution of light inside a photoreactor brings a lot of complexity to the reactor design. Unlike thermochemical reactions, it is not feasible to scale up photoreactions by increasing the dimensions of the reactor due

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

• ; photocatalysis; photochemistry; Introduction Enantioselective catalysis has become a central focus for organic synthetic chemistry, particularly since the Nobel prize was awarded to Sharpless, Knowles, and Noyori for their pioneering work in the field. In the last 15 years, photocatalysis has become a

Formation of an exceptionally stable ketene during phototransformations of bicyclo[2.2.2]oct-5-en-2-ones having mixed chromophores

• Asitanga Ghosh

Beilstein J. Org. Chem. 2020, 16, 2297–2303, doi:10.3762/bjoc.16.190

• position; ketene; mixed chromophores; Introduction Enones exhibit a rich and diverse photochemistry. The deep-seated photochemical rearrangements found in these systems have attracted numerous mechanistic studies. In this context, the photochemistry of α,β-enones A and β,γ-enones B (Figure 1) has become

• an actively researched area for more than two decades [1][2][3][4][5][6], particularly because of their fascinating photochemical rearrangements. In view of their rich photochemistry, it may be expected that incorporation of both enones into the same molecule C would lead to a variety of more

• interesting reactions. Indeed, this type of mixed enone photochemistry is also an attractive field [7][8] for chemists because the photochemistry of such substrates can feature the intramolecular competition of different photochemical rearrangements. For several years, our laboratory (S. Lahiri et al.) is

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• catalysis and photochemistry. Where transition metal catalysis provides one strategy for C–H bond activation, transition-metal-free photochemical C–H fluorination can provide a complementary selectivity via a radical mechanism that proceeds under milder conditions than thermal radical activation methods

• unprecedented attention to photochemistry [70][71]. Increasing interest in photochemistry is often attributed to the ability to access radical intermediates that are otherwise difficult or impossible to obtain by classical chemistry but that can achieve unique chemical reactions complementary to two-electron

• processes [72][73][74][75][76][77]. However, the adoption of photochemistry into the toolbox of the synthetic organic chemist has been hindered by three phenomena: i) simple organic-molecule targets typically do not absorb (or have very small extinction coefficients for) visible light, which is among the